This work was funded by a Faculty Research Grant (Northern Michigan University, awarded to M.A.C.), an undergraduate research fellowship (Northern Michigan University, awarded to J.C), and the Department of Chemistry. The authors wish to thank John Berger (NMU) for assistance with plant tissue preparation, Hannah Hawkins (NMU) for LC-MS maintenance and troubleshooting assistance, and Dr. Ryan Fornwald and his CH 495 (Natural Products Synthesis) students for their preparation the acetyltropine mix. The authors also wish to thank Dr. Daniel Jones (Michigan State University) for acquiring high-resolution MS/MS spectra.

CAUTION: Please consult all relevant material safety data sheets (MSDS) before using the listed chemicals.
1. Sample preparation
CAUTION: Liquid nitrogen can cause cryogen burns. Use cryogen gloves and eye protection in a well-ventilated area. Alkaloid-containing plant samples can be irritating to the skin; always handle them with gloves. Methanol is toxic and flammable and should be handled in a fume hood away from potential ignition sources.
NOTE: In theory, cultivated or wild plant tissue can be used (dried or ground fresh); the below procedure is just that utilized during method development.
<ol>
	<li>If the plant tissue of interest is fresh, freeze it by placing it in a polypropylene conical tube and immersing it in liquid nitrogen for 2-3 min.</li>
	<li>Place the frozen plant tissue into a pre-chilled mortar (in a polystyrene cooler with liquid nitrogen), and using a pre-chilled pestle, grind the tissue to a uniform powder.</li>
	<li>Quickly weigh the desired amount of tissue into a tared polypropylene microcentrifuge tube using a pre-chilled spatula, and immediately add 20% methanol (at room temperature [RT]) at a concentration of 1 mL per every 100 mg of tissue. 
	NOTE: Methanol (20%) is commonly used to extract TAs25. Occasionally, 0.1% formic acid is added, although no difference in extraction efficiency was observed during the development of this method and others.</li>
	<li>Place the capped tubes on a rocking shaker (medium speed) for a minimum of 3 h at RT.</li>
	<li>Centrifuge the tubes at 9464 x g for 10 min. Pipette off the supernatant into an LC-MS autosampler vial, or, if still cloudy, filter through a 0.45 &#181;m syringe filter first. 
	NOTE: The protocol can be paused here, although processed fresh plant samples and extracts should be stored in a -80 &#730;C freezer prior to analysis to avoid any potential alkaloid degradation.</li>
</ol>
2. LC-MS instrument configuration and data collection
CAUTION: Acetonitrile is toxic and flammable; keep away from ignition sources and control vapors using a fume hood. Formic acid is corrosive; avoid skin and eye contact and wear appropriate personal protective equipment.
<ol>
	<li>Use an LC-MS instrument with an electrospray ionization (ESI) source and a reversed-phase HPLC column (C18, 4.6 x 100 mm).</li>
	<li>For HPLC, use 0.1% formic acid in H2O as Solvent A and 0.1% formic acid in acetonitrile as Solvent B; equilibrate the column with 99% A and 1% B. Configure a 30 min gradient of 1%-50% B over 26 min, returning to 1% B at 26.01 min, and holding at 1% B for 4 min. Use a column oven temperature of 45 &#730;C and a flow rate of 0.5 mL/min.</li>
	<li>In the LC-MS method, use the following operating parameters for the mass spectrometer: interface voltage: 4.0 kV, nebulizing gas flow: 3 L/min, heating gas flow: 10 L/min, DL temperature: 250 &#730;C, heat block temperature: 400 &#730;C, interface temperature: 300 &#730;C, drying gas flow: 10 L/min, and collision-induced dissociation (CID) gas (argon) pressure of 17 kPa.</li>
	<li>Build an MS method in ESI positive mode that includes both a Q3 scan and a Q1 scan (100-1000 Da) that functions as a survey event (set to the length of the LC method), with automatic isotope exclusion enabled. Include a product ion scan as a dependent event of the Q1 scan (DD analysis), with a mass window of 50-1000 Da, a collision cell energy of -20 V, and an event time of &#60;0.2 s. 
	NOTE: The count threshold for triggering Q1&#39;s DD product ion scan can be variable, but typically, a level of 7,000-10,000 counts is used. On some instruments, such as the one used to develop the method, the Q3 scan provides greater mass accuracy and sensitivity than Q1 and is included to confirm ions observed in the Q1 scan, although it can be omitted from step 2.4 without issue.</li>
	<li>To the above MS method, add positive-mode PrISs equal to the length of the LC method with collision cell energies of -20 V and event times of 0.75 s. Make sure in all cases, Automatic Isotope Exclude, or De-isotoping functions are enabled. Ensure that the m/z values of interest for TA fragments (in Da, see Figure 1A) are 124.1 (for monosubstituted TAs, mass window of 125-1000 Da), 122.1 and 140.1 (for disubstituted TAs, mass windows beginning at 123 and 141 Da, respectively), and 156.1 and 138.1 (for trisubstituted TAs, mass windows beginning at 157 and 139 Da, respectively). 
	NOTE: During method development, the PrIS were split over two different methods, one for mono- and disubstituted TAs and one for trisubstituted TAs, although they can be split up or combined any way.</li>
	<li>Build a second MS method that includes the parameters in step 2.4.
	<ol>
		<li>To that MS/MS method, add positive-mode NLS equal to the length of the LC method, with collision cell energies of -20 V and event times of 0.75 s. Make sure in all cases, Automatic Isotope Exclude or De-isotoping functions are enabled.</li>
		<li>Ensure that the neutral loss masses of interest for esters on TAs (in Da, see Figure 1B) are 100.05 (for esters derived from tiglic acid, mass window of 110-1000 Da), 60.03 (for acetyl groups, mass window of 100-1000 Da), and 166.06 (phenyllactic or tropic acid esters, mass window of 170-1000 Da).</li>
	</ol>
	</li>
	<li>Download the LC-MS method and create data files for the samples of interest. Once the HPLC column is equilibrated at 45 &#730;C, run the samples of interest in a batch or project file with appropriate extraction solvent blanks between different species or tissue types. A typical injection volume is 10-20 &#181;L. 
	NOTE: At especially high volumes, the mass spectrometer detector may be saturated. If running very concentrated samples, be sure that the ESI source is cleaned and the instrument is tuned regularly. The protocol can be paused here after all data is collected.</li>
</ol>
3. Data analysis
<ol>
	<li>Examine the total ion chromatogram of the Q1 and Q3 scans (and the DD product ion scan), and note the parent mass of any abundant ions which have TA-like features: a) mass &#60;500 Da for the [M+H]+ ion, usually an even-mass, b) typical r.t.s between 2-22 min using the above LC method, and c) fragments from the following list: m/z 93, 124, 142, 140, 122, 138, 156, 174, 110, or 128 Da.</li>
	<li>Examine the PrIS chromatogram/channel for m/z 124, and note which peaks/ions are at which r.t.s (recorded in step 3.1) produce this fragment. Click scan-by-scan through the chromatogram as well as examine the full MS/MS spectra obtained in the DD product ion scan, especially for lower-abundance species. 
	NOTE: A true species containing this fragment will exist for multiple scans and appear in both the Q1 and Q3 scans (if the latter is used). A spreadsheet is attached in the Supporting Information (Supplementary File 1) to aid with&#160;annotations.</li>
	<li>Repeat step 3.2 with the other PrIS chromatograms. As both m/z 122 and 140 are indicative of disubstituted TAs and both m/z 138 and 156 are indicative of trisubstituted TAs, examine these chromatograms/channels together.</li>
	<li>Examine the NLS chromatogram/channels for m/z 100, 60, and 166, and note which peaks/ions at which r.t.s (recorded in step 3.1) produce these neutral losses. As with the PrIS, click scan-by-scan through the chromatogram and compare with the fragmentation obtained in the DD product ion scan, especially for lower-abundance species.</li>
	<li>Using the combination of PrIS and NLS data, supported by the DD product ion scan results, make putative annotations of the observed alkaloids by adding the smallest tropane mass (e.g., 124, 122, or 138) and the neutral loss and then accounting for the remaining leftover mass. 
	NOTE: Typical groups substituting TAs (and their masses in Da) are hydroxyl (18), acetyl (60), propionyl (74), isobutyryl (88), tigloyl (100), saturated tigloyl/2-methylbutyryl (102), or phenyllactate/tropic acid (166).</li>
	<li>Compare annotations for alkaloids to those reported in the literature17 and databases (e.g., MoNA)26 to determine which TA substitution patterns are reported (and which are potentially novel). Additionally, use standards of some common tropane alkaloids (e.g., atropine, littorine, scopolamine) that are commercially available for confirmation.</li>
	<li>For additional structural information for low-abundance samples (the PrIS and NLS may pick up ions below the dependent event thresholds), collect a specific product ion scan (utilizing the mass of interest as the precursor ion) on a more concentrated sample. 
	NOTE: This method was developed on a low-resolution QQQ instrument. For all putative new compounds, a high-resolution MS instrument should be used to obtain accurate mass spectra.</li>
</ol>

Classification of Tropane Alkaloids from Plant Metabolites Using LC-MS/MS

<ol>
	<li>Newman, D. J., Cragg, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+products+as+sources+of+new+drugs+over+the+30+years+from+1981+to+2010.">Natural products as sources of new drugs over the 30 years from 1981 to 2010.</a> J Nat Prod. 75, 311-335 (2012).</li><li>Newman, D. J., Cragg, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+products+as+sources+of+new+drugs+over+the+nearly+four+decades+from+01/1981+to+09/2019.">Natural products as sources of new drugs over the nearly four decades from 01/1981 to 09/2019.</a> J Nat Prod. 83 (3), 770-803 (2020).</li><li>Kohnen-Johannsen, K., Kayser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tropane+alkaloids:+Chemistry,+pharmacology,+biosynthesis+and+production.">Tropane alkaloids: Chemistry, pharmacology, biosynthesis and production.</a> Molecules. 24 (4), 796 (2019).</li><li>Shim, K. H., Kang, M. J., Sharma, N., An, S. S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beauty+of+the+beast:+anticholinergic+tropane+alkaloids+in+therapeutics.">Beauty of the beast: anticholinergic tropane alkaloids in therapeutics.</a> Nat Prod Bioprospect. 12 (1), 33 (2022).</li><li>Web Annex A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=World+Health+Organization+Model+List+of+Essential+Medicines+-+23rd+List,+2023.">World Health Organization Model List of Essential Medicines - 23rd List, 2023.</a> The Selection and Use of Essential Medicines 2023: Executive Summary of the Report of the 24th WHO Expert Committee on the Selection and Use of Essential Medicines. , 24-28 (2023).</li><li>Kerchner, A., Farkas, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Worldwide+poisoning+potential+of+Brugmansia+and+Datura.">Worldwide poisoning potential of Brugmansia and Datura.</a> Forensic Toxicol. 38, 30-41 (2020).</li><li>Hanna, J. P., Schmidley, J. W., Braselton, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Datura+delirium.">Datura delirium.</a> Clin Neuropharmacol. 15, 109-113 (1992).</li><li>Alexander, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Scientific+opinion+of+the+panel+on+contaminants+in+the+food+chain+on+a+request+from+the+European+Commission+on+tropane+alkaloids+(from+Datura+sp.)+as+undesirable+substances+in+animal+feed.">Scientific opinion of the panel on contaminants in the food chain on a request from the European Commission on tropane alkaloids (from Datura sp.) as undesirable substances in animal feed.</a> EFSA J. 691, 1-55 (2008).</li><li>Gonz&#225;lez-G&#243;mez, L., Morante-Zarcero, S., P&#233;rez-Quintanilla, D., Sierra, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Occurrence+and+chemistry+of+Tropane+alkaloids+in+foods,+with+a+focus+on+sample+analysis+methods:+A+review+on+recent+trends+and+technological+advances.">Occurrence and chemistry of Tropane alkaloids in foods, with a focus on sample analysis methods: A review on recent trends and technological advances.</a> Foods. 11 (3), 407 (2022).</li><li>Cirlini, M., Cappucci, V., Galaverna, G., Dall'Asta, C., Bruni, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+sensitive+UHPLC-ESI-MS/MS+method+for+the+determination+of+tropane+alkaloids+in+herbal+teas+and+extracts.">A sensitive UHPLC-ESI-MS/MS method for the determination of tropane alkaloids in herbal teas and extracts.</a> Food Control. 105, 285-291 (2019).</li><li>Amorim Madiera, P. J., Florencio, M. H., Prasain, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applications+of+Tandem+Mass+Spectrometry:+From+Structural+Analysis+to+Fundamental+Studies.">Applications of Tandem Mass Spectrometry: From Structural Analysis to Fundamental Studies.</a> Tandem Mass Spectrometry - Applications and Principles. , (2012).</li><li>Xing, J., Xie, C., Lou, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+applications+of+liquid+chromatography-mass+spectrometry+in+natural+products+bioanalysis.">Recent applications of liquid chromatography-mass spectrometry in natural products bioanalysis.</a> J Pharm Biomed Anal. 44 (2), 368-378 (2007).</li><li>Negrin, A., Long, C., Motley, T. J., Kennelly, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=LC-MS+metabolomics+and+chemotaxonomy+of+caffeine-containing+holly+(Ilex)+species+and+related+taxa+in+the+Aquifoliaceae.">LC-MS metabolomics and chemotaxonomy of caffeine-containing holly (Ilex) species and related taxa in the Aquifoliaceae.</a> J. Agric. Food Chem. 67 (19), 5687-5699 (2019).</li><li>Och, A., Szewczyk, K., Pecio, L., Stochmal, A., Zaluski, D., Bogucka-Kocka, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UPLC-MS/MS+profile+of+alkaloids+with+cytotoxic+properties+of+selected+medicinal+plants+of+the+Berberidaceae+and+Papaveraceae+families.">UPLC-MS/MS profile of alkaloids with cytotoxic properties of selected medicinal plants of the Berberidaceae and Papaveraceae families.</a> Oxid Med Cell Longevity. 2017, 9369872 (2017).</li><li>Li, Y., Pang, T., Shi, J., Liu, X., Deng, J., Lin, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+determination+of+alkaloids+and+their+related+tobacco-specific+nitrosamines+in+tobacco+leaves+using+LC-MS-MS.">Simultaneous determination of alkaloids and their related tobacco-specific nitrosamines in tobacco leaves using LC-MS-MS.</a> J Chromatogr Sci. 53 (10), 1730-1736 (2015).</li><li>Gonz&#225;lez-G&#243;mez, L., Morante-Zarcero, S., Pereira, J. A. M., C&#226;mara, J. S., Sierra, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+analytical+approach+for+determination+of+tropane+alkaloids+in+leafy+vegetables+based+on+&#181;-QuEChERS+combined+with+HPLC-MS/MS.">Improved analytical approach for determination of tropane alkaloids in leafy vegetables based on &#181;-QuEChERS combined with HPLC-MS/MS.</a> Toxins. 14 (10), 650 (2022).</li><li>Cinelli, M. A., Jones, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alkaloids+of+the+Genus+Datura:+Review+of+a+rich+resource+for+natural+product+discovery.">Alkaloids of the Genus Datura: Review of a rich resource for natural product discovery.</a> Molecules. 26, 2629 (2021).</li><li>Gon&#231;alves Dantas, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dereplication+of+tropane+alkaloids+from+four+Erythroxylum+species+using+liquid+chromatography+coupled+with+ESI-MSn+and+HRESIMS.">Dereplication of tropane alkaloids from four Erythroxylum species using liquid chromatography coupled with ESI-MSn and HRESIMS.</a> Rapid Commun Mass Spectrom. 37 (21), e9629 (2023).</li><li>Santos, C. L. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+networking-based+dereplication+of+strictosidine-derived+monoterpene+indole+alkaloids+from+the+curare+ingredient+Strychnos+peckii.">Molecular networking-based dereplication of strictosidine-derived monoterpene indole alkaloids from the curare ingredient Strychnos peckii.</a> Rapid Commun Mass Spectrom. 34 (3), e8683 (2020).</li><li>Qin, G. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MS/MS-based+molecular+networking:+An+efficient+approach+for+natural+products+dereplication.">MS/MS-based molecular networking: An efficient approach for natural products dereplication.</a> Molecules. 28, 157 (2023).</li><li>Du, N., Zhou, W., Jin, H., Liu, Y., Zhou, H., Liang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+tropane+and+cinnamamide+alkaloids+from+Scopolia+tangutica+by+high-performance+liquid+chromatography+with+quadrupole+time-of-flight+tandem+mass+spectrometry.">Characterization of tropane and cinnamamide alkaloids from Scopolia tangutica by high-performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry.</a> J Sep Sci. 42 (6), 1163-1173 (2019).</li><li>Agnes, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implementation+of+a+MS/MS+database+for+isoquinoline+alkaloids+and+other+annonaceous+metabolites.">Implementation of a MS/MS database for isoquinoline alkaloids and other annonaceous metabolites.</a> Sci Data. 9 (1), 270 (2022).</li><li>Sixto, A., P&#233;rez-Parada, A., Niell, S., Heinzen, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GC-MS+and+LC-MS/MS+workflows+for+the+identification+and+quantitation+of+pyrrolizidine+alkaloids+in+plant+extracts,+a+case+study:+Echium+plantagineum.">GC-MS and LC-MS/MS workflows for the identification and quantitation of pyrrolizidine alkaloids in plant extracts, a case study: Echium plantagineum.</a> Rev Bras Farmacog. 29 (4), 500-503 (2019).</li><li>Wang, H., Xu, X., Wang, X., Guo, W., Jia, W., Zhang, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+analytical+strategy+for+discovering+structural+analogues+of+alkaloids+in+plant+food+using+characteristic+structural+fragments+extraction+by+high+resolution+orbitrap+mass+spectrometry.">An analytical strategy for discovering structural analogues of alkaloids in plant food using characteristic structural fragments extraction by high resolution orbitrap mass spectrometry.</a> LWT- Sci Technol. 154, 112329 (2022).</li><li>Parks, H. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redirecting+tropane+alkaloid+metabolism+reveals+pyrrolidine+alkaloid+diversity+in+Atropa+belladonna.">Redirecting tropane alkaloid metabolism reveals pyrrolidine alkaloid diversity in Atropa belladonna.</a> New Phytol. 237 (5), 1810-1825 (2023).</li><li>. MassBank of North America Available from: <a target="_blank" href="https://mona.fiehnlab.ucdavis.edu">https://mona.fiehnlab.ucdavis.edu</a> (2024)</li><li>Maier, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorodaturatin+und+Homofluorodaturatin+-+zwei+neue+&#946;-carbolinderivate+in+Samen+von+Datura+stramonium+L.+var.+stramonium.">Fluorodaturatin und Homofluorodaturatin - zwei neue &#946;-carbolinderivate in Samen von Datura stramonium L. var. stramonium.</a> Monatsh Chem. 112, 1425-1439 (1981).</li><li>Jennett-Siems, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemotaxonomy+of+the+pantropical+genus+Merremia+(Convolvulaceae)+based+on+the+distribution+of+tropane+alkaloids.">Chemotaxonomy of the pantropical genus Merremia (Convolvulaceae) based on the distribution of tropane alkaloids.</a> Phytochemistry. 66, 1448-1464 (2005).</li><li>Kohnen, K. L., Sezgin, S., Spiteller, M., Hagels, H., Kayser, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localization+and+organization+of+scopolamine+biosynthesis+in+Duboisia+myoporoides+R.">Localization and organization of scopolamine biosynthesis in Duboisia myoporoides R.</a> Br. Plant Cell Physiol. 59 (1), 107-118 (2018).</li><li>Guan, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Full+collision+energy+ramp-MS2+spectrum+in+structural+analysis+relying+on+MS/MS.">Full collision energy ramp-MS2 spectrum in structural analysis relying on MS/MS.</a> Anal Chem. 93 (46), 15381-15389 (2021).</li><li>Al Balkhi, M. H., Schlitz, S., Lesur, D., Lanoue, A., Wadouachi, M., Boitel-Conti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Norlittorine+and+norhyoscyamine+identified+as+products+of+littorine+and+hyoscyamine+metabolism+by+13C-labeling+in+Datura+innoxia+hairy+roots.">Norlittorine and norhyoscyamine identified as products of littorine and hyoscyamine metabolism by 13C-labeling in Datura innoxia hairy roots.</a> Phytochemistry. 74, 105-114 (2012).</li><li>Sumner, L. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proposed+minimum+reporting+standards+for+chemical+analysis.">Proposed minimum reporting standards for chemical analysis.</a> Metabolomics. 3, 211-221 (2007).</li><li>Gambaro, V., Labbe, C., Castillo, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angeloyl,+Tigloyl+and+Senecioyloxytropane+Alkaloids+from+Schizanthus+hookerii.">Angeloyl, Tigloyl and Senecioyloxytropane Alkaloids from Schizanthus hookerii.</a> Phytochemistry. 22 (8), 1838-1839 (1983).</li><li>Christen, P., Cretton, S., Humam, M., Bieri, S., Mu&#241;oz, O., Joseph-Nathan, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemistry+and+biological+activity+of+alkaloids+from+the+genus+Schizanthus.">Chemistry and biological activity of alkaloids from the genus Schizanthus.</a> Phytochem Rev. 19, 615-641 (2020).</li><li>Lounasmaa, M., Tamminen, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Tropane+Alkaloids.">The Tropane Alkaloids.</a> The Alkaloids: Chemistry and Pharmacology. , (1993).</li></ol>

The authors have no conflicts of interest to disclose.

Although&#160;the instrument parameters provided in the protocol allow for satisfactory performance, the successful use of this method may require careful attention to or optimization of several critical steps. While the HPLC solvent gradient provided in step 2.2 is generally appropriate for tropane alkaloids, it may need to be modified depending on the tropane alkaloid profile of the sample or plant species being examined. The sample injection volume can also be changed depending on the sensitivity of the instrument and...

Although fully synthetic molecules have become more prominent in drug discovery in recent decades, nearly two-thirds of all approved drugs from the last 39 years are natural products or natural-product-inspired,1,2&#160;underscoring the continued importance of natural products research. Alkaloids, certain nitrogen-containing natural products, are especially prized for their medicinal properties. Tropane alkaloids (TAs) containing the [3.2.1.]-bicyclic nitrogen-containing system, are produced mostly by plants in the Solanaceae (nightshade), Erythroxylaceae, and Convolvulaceae families. Examples include atropine, scopolamine, and cocaine; multiple semi-synthetic or synthetic tropanes are also used clinically3. TAs and their derivatives are used to treat many conditions3,4 and several of these drugs appear on the WHO&#39;s 2023 List of Essential Medicines5. Because of their potent activities, TAs are also used recreationally (as stimulants or deliriants) and can cause poisoning upon ingestion of plants (or preparations) that contain them6,7. TAs are undesirable in human and animal food8 and can taint teas, spices, grains, honey, and herbal supplements9,10.&#160;Because of both their medicinal promise and ability to poison, analytical methods that can aid in the discovery of new TAs (and identification of known TAs) are useful.
In tandem mass spectrometry (MS/MS), &#34;mass filters&#34; (e.g., quadrupoles, time-of-flight tubes) are coupled together physically (&#34;in-space&#34;), or an instrument employs additional &#34;in-time&#34; reaction/separation steps. In-space MS/MS uses different modes to select and fragment different ions at the different mass filters (e.g., the quadrupoles of a triple-quadrupole or QQQ instrument). These different modes can be used to determine which specific fragments are made by a given ion (product ion scan), which ions in a sample yield certain fragments (precursor ion scan or PrIS) or undergo losses of a characteristic mass (neutral loss scan or NLS), or which specific compounds possess which specific fragments (multiple reaction monitoring). MS/MS, therefore, provides fragments that are useful for proposing structures for new compounds or confirming an existing compound&#39;s presence. MS/MS is increasingly used in the drug discovery, natural products chemistry, and metabolomics fields11,12,&#160;and has been used to profile alkaloid-containing species (for phytochemical characterization or chemotaxonomic analysis) and to detect and quantify specific alkaloids in food or medicinal plants10,13,14,15,16.
Despite the many mass spectrometry techniques available, there are challenges in finding new alkaloids. In addition to finding a candidate organism to screen, a full structural confirmation of an alkaloid is an arduous process that may include many different analytical techniques. Additionally, researchers could isolate a compound that is already known, wasting labor, time, and resources. This is especially difficult for TAs, where hundreds, if not thousands of TAs, many of which are isomeric with one another, are reported. The process of &#34;identifying the knowns and distinguishing them from the unknowns&#34; is known as dereplication. Databases of the retention times (r.t.s) and mass fragments of different TAs and other compounds are published to aid with this process17,18.&#160;Nonetheless, dereplication is laborious; merely annotating (i.e., assigning putative structures to) the alkaloids in a sample&#39;s entire LC-MS/MS chromatogram is time-consuming. Recently, both molecular networking19,20 and manual dereplication18,21,22 have been used for benzylisoquinoline, monoterpene indole, and tropane alkaloids, and PrISs have been used for &#34;structural filtering&#34; of spectra to identify pyrrolizidine and solanine-type alkaloids23,24.&#160;There are no specific methods or workflows available for rapid LC-MS/MS-based dereplication of TA-containing samples, however, even though TAs possess common, easily-identifiable fragments (Figure 1). The method described here uses a combination of data-dependent (DD) product ion scans, PrISs, and NLSs to annotate and classify TA structures in plants based on both the distinct fragmentation patterns for mono-, di-, and trisubstituted tropanes (Figure 1A) and the losses of common ester groups found in these alkaloids (Figure 1B). The study organisms are several species in the nightshade genus Datura. A rich source of diverse TAs, Datura has been used&#160;throughout the world&#39;s history for medicinal and cultural purposes17- and is a challenging matrix to dereplicate because of its numerous, structurally similar TAs, providing us with appealing samples upon which to test our method.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Acetonitrile, For UHPLC, suitable for mass spectometry</td>
			<td>Sigma-Aldrich</td>
			<td>900667</td>
			<td>HPLC solvent</td>
		</tr>
		<tr>
			<td>Argon gas</td>
			<td>AirGas</td>
			<td>AR UHP300</td>
			<td>CID gas</td>
		</tr>
		<tr>
			<td>Formic acid, 99% for analysis</td>
			<td>Thermo Scientific</td>
			<td>AC270480010</td>
			<td>HPLC additive</td>
		</tr>
		<tr>
			<td>Guard column holder</td>
			<td>Restek</td>
			<td>25812</td>
			<td></td>
		</tr>
		<tr>
			<td>HPLC, Shimadzu LC-2030C 3D Plus</td>
			<td>Shimadzu</td>
			<td>228-65802-58</td>
			<td>HPLC column</td>
		</tr>
		<tr>
			<td>LCMS, Shimdazu LCMS-8045</td>
			<td>Shimadzu</td>
			<td>225-31800-44</td>
			<td>Mass spectrometer; we ran LabSolutions software, which is standard for Shimadzu instruments</td>
		</tr>
		<tr>
			<td>Liquid nitrogen</td>
			<td>AirGas</td>
			<td>NI 180LT22</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol, for HPLC/UHPLC/LCMS</td>
			<td>VWR</td>
			<td>BDH 85800.400</td>
			<td>For making extraction solvent</td>
		</tr>
		<tr>
			<td>Microcentrifuge&#160;</td>
			<td>VWR</td>
			<td>2400-37</td>
			<td></td>
		</tr>
		<tr>
			<td>Microcentrifuge tubes, 1.5 mL</td>
			<td>Fisher Scientific</td>
			<td>05-408-129</td>
			<td></td>
		</tr>
		<tr>
			<td>Mortar&#160;</td>
			<td>Fisher Scientific</td>
			<td>FB961C</td>
			<td>For grinding plant tissues</td>
		</tr>
		<tr>
			<td>Pestle</td>
			<td>Fisher Scientific</td>
			<td>FB961M</td>
			<td>For grinding plant tissues</td>
		</tr>
		<tr>
			<td>Pipette 1000 mL</td>
			<td>Gilson&#160;</td>
			<td>F144059M</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette tip 1000 mL</td>
			<td>Fisher scientific</td>
			<td>02-707-404</td>
			<td></td>
		</tr>
		<tr>
			<td>Plant tissues</td>
			<td>Various sources</td>
			<td>N/A</td>
			<td>Can be anything wild or cultivated</td>
		</tr>
		<tr>
			<td>Polypropylene conical tubes, 15 mL</td>
			<td>Fisher Scientific</td>
			<td>05-539-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Polystyrene cooler</td>
			<td>ULINE</td>
			<td>S-18312</td>
			<td>The type of coolers that reagents for molecular biology are shipped in would be appropriate</td>
		</tr>
		<tr>
			<td>Roc C18 3 &#181;m, 100 mm x 4.6 mm</td>
			<td>Restek</td>
			<td>9534315</td>
			<td>HPLC column</td>
		</tr>
		<tr>
			<td>Roc C18, 10 mm x 4 mm</td>
			<td>Restek</td>
			<td>953450210</td>
			<td>Guard column</td>
		</tr>
		<tr>
			<td>Rocking shaker</td>
			<td>Themo Scientific</td>
			<td>11-676-680</td>
			<td></td>
		</tr>
		<tr>
			<td>Screw thread vial convenience kit (9 mm)</td>
			<td>Fisher scientific</td>
			<td>13-622-190</td>
			<td>LCMS autosampler vials</td>
		</tr>
		<tr>
			<td>Syringe, 3 mL</td>
			<td>Fisher Scientific</td>
			<td>03-377-27</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe filter 0.45 &#181;m&#160;</td>
			<td>Avantor/VWR</td>
			<td>76479-008</td>
			<td></td>
		</tr>
		<tr>
			<td>Water, for use in liquid chromatography and mass spectrometry</td>
			<td>JT Baker</td>
			<td>9831-03</td>
			<td>For making extraction solvent</td>
		</tr>
		<tr>
			<td>Water solution, contains 0.1% v/v formic acid, For UHPLC, suitable for mass spectometry</td>
			<td>Sigma-Aldrich</td>
			<td>900687-1L</td>
			<td>HPLC solvent</td>
		</tr>
	</tbody>
</table>

applications of liquid-chromatography tandem mass spectrometry in natural products research: tropane alkaloids as a case study

Although many drugs utilized today are synthetic in origin, natural products still provide a rich source of novel chemical diversity and bioactivity, and can yield promising leads for resistant or emerging diseases. The challenge, however, is twofold: not only must researchers find natural products and elucidate their structures, but they must also identify what is worth isolating and assaying (and what is already known - a process known as dereplication). With the advent of modern analytical instrumentation, the pace of natural product discovery and dereplication has accelerated. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become an especially valuable technique for identifying and classifying chemical structures. Tropane alkaloids (TAs) are plant-derived compounds of great medicinal and toxicological significance. In this study, we developed an LC-MS/MS-based screening workflow utilizing the multiple MS/MS configurations available on a triple-quadrupole (QQQ) mass spectrometer to annotate and classify TA structures based on their distinct fragmentation patterns. By using a combination of data-dependent (DD) product ion scans, precursor ion scans (PrIS), and neutral loss scans (NLS), we applied this method to TA-rich extracts of the nightshades Datura stramonium and Datura metel. This method is rapid, sensitive, and was successfully employed for both preliminary dereplication of complex TA-containing samples and for the discovery of a novel candidate for isolation, purification (and eventual bioassay).

To demonstrate the method&#39;s effectiveness, a standard mix of TAs (10 &#181;g/mL each of an acetyltropine/acetylpseudotropine mix [monosubstituted], 10 &#181;g/mL each of a mixture of two anisodamine isomers [disubstituted], along with hyoscyamine [monosubstituted], littorine [monosubstituted], and scopolamine [trisubstituted]) was analyzed as a positive control (Figure 2). A full Q1 scan chromatogram (displayed in the base peak chromatogram view) is shown in Figure 2...

Read this Scientific Article Protocol about Applications of Liquid Chromatography-Tandem Mass Spectrometry in Natural Products Research: Tropane Alkaloids as a Case Study at JoVE.com

Author Spotlight: Discovering New Alkaloids in Plants with Advanced Mass Spectrometry Techniques

We present a method for rapid mass spectrometry (MS)/mass spectrometry (MS)-based annotation and classification of tropane alkaloids, useful for both preliminary dereplication of tropane-containing samples and discovery of novel alkaloids for isolation.

Applications of Liquid-Chromatography Tandem Mass Spectrometry in Natural Products Research: Tropane Alkaloids as a Case Study

Although many drugs utilized today are synthetic in origin, natural products still provide a rich source of novel chemical diversity and bioactivity, and ...

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605 Views.  Northern Michigan University. We present a method for rapid mass spectrometry (MS)/mass spectrometry (MS)-based annotation and classification of tropane alkaloids, useful for both preliminary dereplication of tropane-containing samples and discovery of novel alkaloids for isolation.

Video: Author Spotlight: Discovering New Alkaloids in Plants with Advanced Mass Spectrometry Techniques

Large Scale Non-targeted Metabolomic Profiling of Serum by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS)

Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to investigate metabolism. The approach offers an unbiased and in-depth analysis that can enable the development of diagnostic tests, novel therapies, and further our understanding of disease processes. The inherent chemical diversity of the metabolome creates significant analytical challenges and there is no single experimental approach that can detect all metabolites. Additionally, the biological variation in individual metabolism and the dependence of metabolism on environmental factors necessitates large sample numbers to achieve the appropriate statistical power required for meaningful biological interpretation. To address these challenges, this tutorial outlines an analytical workflow for large scale non-targeted metabolite profiling of serum by UPLC-MS. The procedure includes guidelines for sample organization and preparation, data acquisition, quality control, and metabolite identification and will enable reliable acquisition of data for large experiments and provide a starting point for laboratories new to non-targeted metabolite profiling by UPLC-MS.

Large Scale Non-targeted Metabolomic Profiling of Serum by Ultra Performance Liquid Chromatography-Mass Spectrometry UPLC-MS

Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to investigate metabolism. This article outlines a typical workflow utilized for non-targeted metabolite profiling of serum including sample organization and preparation, data acquisition, data analysis, quality control, and metabolite identification.

Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to ...

Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry (UPLC-HRMS)

Here we present a workflow to analyze the metabolic profiles for biological samples of interest including; cells, serum, or tissue. The sample is first separated into polar and non-polar fractions by a liquid-liquid phase extraction, and partially purified to facilitate downstream analysis. Both aqueous (polar metabolites) and organic (non-polar metabolites) phases of the initial extraction are processed to survey a broad range of metabolites. Metabolites are separated by different liquid chromatography methods based upon their partition properties. In this method, we present microflow ultra-performance (UP)LC methods, but the protocol is scalable to higher flows and lower pressures. Introduction into the mass spectrometer can be through either general or compound optimized source conditions. Detection of a broad range of ions is carried out in full scan mode in both positive and negative mode over a broad m/z range using high resolution on a recently calibrated instrument. Label-free differential analysis is carried out on bioinformatics platforms. Applications of this approach include metabolic pathway screening, biomarker discovery, and drug development.

Untargeted Metabolomics from Biological Sources Using Ultraperformance Liquid Chromatography-High Resolution Mass Spectrometry UPLC-HRMS

Untargeted metabolomics provides a hypothesis generating snapshot of a metabolic profile. This protocol will demonstrate the extraction and analysis of metabolites from cells, serum, or tissue. A range of metabolites are surveyed using liquid-liquid phase extraction, microflow ultraperformance liquid chromatography/high-resolution mass spectrometry (UPLC-HRMS) coupled to differential analysis software.

Here we present a workflow to analyze the metabolic profiles for biological samples of interest including; cells, serum, or tissue. The sample is first ...

Radiolabeling and Quantification of Cellular Levels of Phosphoinositides by High Performance Liquid Chromatography-coupled Flow Scintillation

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular identity and function. Each of the seven PtdInsPs varies in their distribution and abundance, which are tightly regulated by specific kinases and phosphatases. The abundance of PtdInsPs can change abruptly in response to various signaling events or disturbance of the regulatory machinery. To understand how these events lead to changes in the amount of PtdInsPs and their resulting impact, it is important to quantify PtdInsP levels before and after a signaling event or between control and abnormal conditions. However, due to their low abundance and similarity, quantifying the relative amounts of each PtdInsP can be challenging. This article describes a method for quantifying PtdInsP levels by metabolically labeling cells with 3H-myo-inositol, which is incorporated into PtdInsPs. Phospholipids are then precipitated and deacylated. The resulting soluble 3H-glycero-inositides are further extracted, separated by high-performance liquid chromatography (HPLC), and detected by flow scintillation. The labeling and processing of yeast samples is described in detail, as well as the instrumental setup for the HPLC and flow scintillator. Despite losing structural information regarding acyl chain content, this method is sensitive and can be optimized to concurrently quantify all seven PtdInsPs in cells.

Phosphoinositides are signaling lipids whose relative abundance rapidly changes in response to various stimuli. This article describes a method to measure the abundance of phosphoinositides by metabolically labeling cells with 3H-myo-inositol, followed by extraction and deacylation. Extracted glycero-inositides are then separated by high-performance liquid chromatography and quantified by flow scintillation.

Phosphoinositides (PtdInsPs) are essential signaling lipids responsible for recruiting specific effectors and conferring organelles with molecular ...

An HS-MRM Assay for the Quantification of Host-cell Proteins in Protein Biopharmaceuticals by Liquid Chromatography Ion Mobility QTOF Mass Spectrometry

The analysis of low-level (1-100 ppm) protein impurities (e.g., host-cell proteins (HCPs)) in protein biotherapeutics is a challenging assay requiring high sensitivity and a wide dynamic range. Mass spectrometry-based quantification assays for proteins typically involve protein digestion followed by the selective reaction monitoring/multiple reaction monitoring (SRM/MRM) quantification of peptides using a low-resolution (Rs ~1,000) tandem quadrupole mass spectrometer. One of the limitations of this approach is the interference phenomenon observed when the peptide of interest has the "same" precursor and fragment mass (in terms of m/z values) as other co-eluting peptides present in the sample (within a 1-Da window). To avoid this phenomenon, we propose an alternative mass spectrometric approach, a high selectivity (HS) MRM assay that combines the ion mobility separation of peptide precursors with the high-resolution (Rs ~30,000) MS detection of peptide fragments. We explored the capabilities of this approach to quantify low-abundance peptide standards spiked in a monoclonal antibody (mAb) digest and demonstrated that it has the sensitivity and dynamic range (at least 3 orders of magnitude) typically achieved in HCP analysis. All six peptide standards were detected at concentrations as low as 0.1 nM (1 femtomole loaded on a 2.1-mm ID chromatographic column) in the presence of a high-abundance peptide background (2 &#181;g of a mAb digest loaded on-column). When considering the MW of rabbit phosphorylase (97.2 kDa), from which the spiked peptides were derived, the LOQ of this assay is lower than 50 ppm. Relative standard deviations (RSD) of peak areas (n = 4 replicates) were less than 15% across the entire concentration range investigated (0.1-100 nM or 1-1,000 ppm) in this study.

Here, we describe a chromatographic assay coupled with the ion mobility separation of peptide precursors followed by the high-resolution (~30,000) MS-detection of peptide fragments for the quantification of spiked peptide standards in a monoclonal antibody digest.

The analysis of low-level (1-100 ppm) protein impurities (e.g., host-cell proteins (HCPs)) in protein biotherapeutics is a challenging assay requiring ...

A Convenient Method for Extraction and Analysis with High-Pressure Liquid Chromatography of Catecholamine Neurotransmitters and Their Metabolites

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and related diseases, but their precise measurement is still a challenge. Many protocols have been described for neurotransmitter measurement by a variety of instruments, including high-pressure liquid chromatography (HPLC). However, there are shortcomings, such as complicated operation or hard-to-detect multiple targets, which cannot be avoided, and presently, the dominant analysis technique is still HPLC coupled with sensitive electrochemical or fluorimetric detection, due to its high sensitivity and good selectivity. Here, a detailed protocol is described for the pretreatment and detection of catecholamines with high pressure liquid chromatography with electrochemical detection (HPLC-ECD) in real urine samples of infants, using electrospun composite nanofibers composed of polymeric crown ether with polystyrene as adsorbent, also known as the packed-fiber solid phase extraction (PFSPE) method. We show how urine samples can be easily precleaned by a nanofiber-packed solid phase column, and how the analytes in the sample can be rapidly enriched, desorbed, and detected on an ECD system. PFSPE greatly simplifies the pretreatment procedures for biological samples, allowing for decreased time, expense, and reduction of the loss of targets. 
Overall, this work illustrates a simple and convenient protocol for solid-phase extraction coupled to an HPLC-ECD system for simultaneous determination of three monoamine neurotransmitters (norepinephrine (NE), epinephrine (E), dopamine (DA)) and two of their metabolites (3-methoxy-4-hydroxyphenylglycol (MHPG) and 3,4-dihydroxy-phenylacetic acid (DOPAC)) in infants' urine. The established protocol was applied to assess the differences of urinary catecholamines and their metabolites between high-risk infants with perinatal brain damage and healthy controls. Comparative analysis revealed a significant difference in urinary MHPG between the two groups, indicating that the catecholamine metabolites may be an important candidate marker for early diagnosis of cases at risk for brain damage in infants.

We present a convenient solid-phase extraction coupled to high-pressure liquid chromatography (HPLC) with electrochemical detection (ECD) for simultaneous determination of three monoamine neurotransmitters and two of their metabolites in infants' urine. We also identify the metabolite MHPG as a potential biomarker for the early diagnosis of brain damage for infants.

The extraction and analysis of catecholamine neurotransmitters in biological fluids is of great importance in assessing nervous system function and ...

Employing Pressurized Hot Water Extraction (PHWE) to Explore Natural Products Chemistry in the Undergraduate Laboratory

A recently developed pressurized hot water extraction (PHWE) method which utilizes an unmodified household espresso machine to facilitate natural products research has also found applications as an effective teaching tool. Specifically, this technique has been used to introduce second- and third-year undergraduates to aspects of natural products chemistry in the laboratory. In this report, two experiments are presented: the PHWE of eugenol and acetyleugenol from cloves and the PHWE of seselin and (+)-epoxysuberosin from the endemic Australian plant species Correa reflexa. By employing PHWE in these experiments, the crude clove extract, enriched in eugenol and acetyleugenol, was obtained in 4-9% w/w from cloves by second-year undergraduates and seselin and (+)-epoxysuberosin were isolated in yields of up to 1.1% w/w and 0.9% w/w from C. reflexa by third-year students. The former exercise was developed as a replacement for the traditional steam distillation experiment providing an introduction to extraction and separation techniques, while the latter activity featured guided-inquiry teaching methods in an effort to simulate natural products bioprospecting. This primarily derives from the rapid nature of this PHWE technique relative to traditional extraction methods that are often incompatible with the time constraints associated with undergraduate laboratory experiments. This rapid and practical PHWE method can be used to efficiently isolate various classes of organic molecules from a range of plant species. The complementary nature of this technique relative to more traditional methods has also been demonstrated previously.

Employing Pressurized Hot Water Extraction PHWE to Explore Natural Products Chemistry in the Undergraduate Laboratory

Here, we employ a pressurized hot water extraction (PHWE) method, which utilizes an unmodified household espresso machine to introduce undergraduates to natural products chemistry in the laboratory. Two experiments are presented: PHWE of eugenol and acetyleugenol from cloves and PHWE of seselin and (+)-epoxysuberosin from the Australian plant Correa reflexa.

A recently developed pressurized hot water extraction (PHWE) method which utilizes an unmodified household espresso machine to facilitate natural products ...

Large-scale Top-down Proteomics Using Capillary Zone Electrophoresis Tandem Mass Spectrometry

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down proteomics that aims to characterize proteoforms in complex proteomes. However, the application of CZE-MS/MS for large-scale top-down proteomics has been impeded by the low sample-loading capacity and narrow separation window of CZE. Here, a protocol is described using CZE-MS/MS with a microliter-scale sample-loading volume and a 90-min separation window for large-scale top-down proteomics. The CZE-MS/MS platform is based on a linear polyacrylamide (LPA)-coated separation capillary with extremely low electroosmotic flow, a dynamic pH-junction-based online sample concentration method with a high efficiency for protein stacking, an electro-kinetically pumped sheath flow CE-MS interface with extremely high sensitivity, and an ion trap mass spectrometer with high mass resolution and scan speed. The platform can be used for the high-resolution characterization of simple intact protein samples and the large-scale characterization of proteoforms in various complex proteomes. As an example, a highly efficient separation of a standard protein mixture and a highly sensitive detection of many impurities using the platform is demonstrated. As another example, this platform can produce over 500 proteoform and 190 protein identifications from an Escherichia coli proteome in a single CZE-MS/MS run.

A detailed protocol is described for the separation, identification, and characterization of proteoforms in protein samples using capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS). The protocol can be used for the high-resolution characterization of proteoforms in simple protein samples and the large-scale identification of proteoforms in complex proteome samples.

Capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) has been recognized as a useful tool for top-down ...

Mass Spectrometry-Guided Genome Mining as a Tool to Uncover Novel Natural Products

The chemical space covered by natural products is immense and widely unrecognized. Therefore, convenient methodologies to perform wide-ranging evaluation of their functions in nature and potential human benefits (e.g., for drug discovery applications) are desired. This protocol describes the combination of genome mining (GM) and molecular networking (MN), two contemporary approaches that match gene cluster-encoded annotations in whole genome sequencing with chemical structure signatures from crude metabolic extracts. This is the first step towards the discovery of new natural entities. These concepts, when applied together, are defined here as MS-guided genome mining. In this method, the main components are previously designated (using MN), and structurally related new candidates are associated with genome sequence annotations (using GM). Combining GM and MN is a profitable strategy to target new molecule backbones or harvest metabolic profiles in order to identify analogues from already known compounds.

A mass spectrometry-guided genome mining protocol is established and described here. It is based on genome sequence information and LC-MS/MS analysis and aims to facilitate identification of molecules from complex microbial and plant extracts.

The chemical space covered by natural products is immense and widely unrecognized. Therefore, convenient methodologies to perform wide-ranging evaluation ...

Gas Chromatography-Mass Spectrometry Paired with Total Vaporization Solid-Phase Microextraction as a Forensic Tool

Gas Chromatography &#8211; Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including controlled substances, ignitable liquids, and explosives. GC-MS can be coupled with Solid-Phase Microextraction (SPME), in which a fiber with a sorptive coating is placed into the headspace above a sample or immersed in a liquid sample. Analytes are sorbed onto the fiber which is then placed inside the heated GC inlet for desorption. Total Vaporization Solid-Phase Microextraction (TV-SPME) utilizes the same technique as immersion SPME but immerses the fiber into a completely vaporized sample extract. This complete vaporization results in a partition between only the vapor phase and the SPME fiber without interference from a liquid phase or any insoluble materials. Depending upon the boiling point of the solvent used, TV-SPME allows for large sample volumes (e.g., up to hundreds of microliters). On-fiber derivatization may also be performed using TV-SPME. TV-SPME has been used to analyze drugs and their metabolites in hair, urine, and saliva. This simple technique has also been applied to street drugs, lipids, fuel samples, post-blast explosive residues, and pollutants in water. This paper highlights the use of TV-SPME to identify illegal adulterants in very small samples (microliter quantities) of alcoholic beverages. Both gamma-hydroxybutyrate (GHB) and gamma-butyrolactone (GBL) were identified at levels that would be found in spiked drinks. Derivatization by a trimethylsilyl agent allowed for conversion of the aqueous matrix and GHB into their TMS derivatives. Overall, TV-SPME is quick, easy, and requires no sample preparation aside from placing the sample into a headspace vial.

Total Vaporization Solid Phase Microextraction (TV-SPME) completely vaporizes a liquid sample whilst analytes are sorbed onto a SPME fiber. This allows for partitioning of the analyte between only the solvent vapor and the SPME fiber coating.

Gas Chromatography &#8211; Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including ...

Extraction of Non-Protein Amino Acids from Cyanobacteria for Liquid Chromatography-Tandem Mass Spectrometry Analysis

Non-protein amino acids (NPAAs) are a large class of amino acids (AAs) that are not genetically encoded for translation into proteins. The analysis of NPAAs can provide crucial information about cellular uptake and/or function, metabolic pathways, and potential toxicity. &#946;-methylamino-L-alanine (BMAA) is a neurotoxic NPAA produced by various algae species and is associated with an increased risk for neurodegenerative diseases, which has led to significant research interest. There are numerous ways to extract AAs for analysis, with liquid chromatography-tandem mass spectrometry being the most common, requiring protein precipitation followed by acid hydrolysis of the protein pellet. Studies on the presence of BMAA in algal species provide contradictory results, with the use of unvalidated sample preparation/extraction and analysis a primary cause. Like most NPAAs, protein precipitation in 10% aqueous TCA and hydrolysis with fuming HCl is the most appropriate form of extraction for BMAA and its isomers aminoethylglycine (AEG) and 2,4-diaminobutyric acid (2,4-DAB). The present protocol describes the steps in a validated NPAA extraction method commonly used in research and teaching laboratories.

The present protocol describes the extraction of non-protein amino acids from biological matrices via trichloroacetic acid (TCA) protein precipitation and acid hydrolysis before analysis using liquid chromatography-tandem mass spectrometry.

Non-protein amino acids (NPAAs) are a large class of amino acids (AAs) that are not genetically encoded for translation into proteins. The analysis of ...