Funding for this research was provided in part by the USDA-ARS Research Associate Program and the USDA Crop Germplasm Committee.

1. Amylose Determination from Potato Tuber Starch
<ol>
	<li>Peel and cut fresh tubers into small cubes.</li>
	<li>Place potato cubes in small brown bags and store overnight at -80 &#176;C.</li>
	<li>Transfer potato cubes to nylon bags and for freeze drying.</li>
	<li>After freeze dried, grind the potato sample into powder using mortar and pestle or a Wiley Mill.</li>
	<li>In a 50 ml tube, add 20-30 mg of the freeze-dried, ground tuber sample.</li>
	<li>Prepare a solution of 45% (w/v) perchloric acid (mix 24.4 ml of 60% perchloric acid and 25.6 ml of ultra-pure water.</li>
	<li>Add 500 &#956;l of 45% (w/v) perchloric acid and shake or swirl it to disperse starch granules.</li>
	<li>After a four-minute incubation period at room temperature, add 16 ml of ultra-pure water to the solution and mix by vortexing.</li>
	<li>After non-soluble material has settled to the bottom of the tube (7-10 min&#160;later), transfer 40 &#956;l of the solution to a microtiter plate (avoiding the pipetting of any particles).</li>
	<li>Add 50 &#956;l of iodine solution (2 g KI + 1 g I2 in 900 ml of ultra-pure water) and mix the sample by pipetting.</li>
	<li>Read the absorbance at 550 nm and 620 nm immediately.</li>
	<li>Determine the amylose percentage after comparing the amylose/amylopectin ratio of each sample (620 nm/550 nm absorbance) with a standard curve generated from amylose and amylopectin solutions at a range of concentrations. This procedure will be described next. Read the blank (iodine solution and perchloric acid) along with the test samples. Use blanked data for the analyses.</li>
</ol>
2. Amylose/amylopectin Curve
<ol>
	<li>In separate tubes weigh 12.5 mg of amylose and 12.5 mg of amylopectin.</li>
	<li>Add to each tube 5 ml of 45% (w/v) perchloric acid and dissolve completely.</li>
	<li>For each of the solutions (amylose and amylopectin), bring to a final volume of 50 ml with ultra-pure water.</li>
	<li>Mix 6.25 ml of amylose stock from the previous step with 18.75 ml ultra-pure water. This will make a 6.25 mg/ml amylose solution.</li>
	<li>Repeat the procedure for the amylopectin solution.</li>
	<li>Using the amylose and amylopectin standard solutions from steps 2.4 and 2.5, prepare the percent amylose standards which are 0-100% amylose (100-0% amylopectin) to a final volume of 5 ml to create the standard curve in 10% intervals. 
	For example, to prepare: 
	The 0% amylose / 100% amylopectin standard, pipette 5 ml amylopectin solution. 
	The 10% amylose / 90% amylopectin standard, combine 0.5 ml amylose and 4.5 ml amylopectin solutions. 
	The 20% amylose / 80% amylopectin standard, combine 1.0 ml amylose and 4.0 ml amylopectin solutions. 
	The 30% amylose / 70% amylopectin standard, combine 1.5 ml amylose and 3.5 ml amylopectin solutions. 
	The 40% amylose / 60% amylopectin standard, combine 2.0 ml amylose and 2.0 ml amylopectin solutions. 
	The 50% amylose / 50% amylopectin standard, combine 2.5 ml amylose and 2.5 ml amylopectin solutions. 
	The 60% amylose / 40% amylopectin standard, combine 3.0 ml amylose and 2.0 ml amylopectin, and so on).</li>
	<li>Transfer 40 &#956;l of each standard mixture to a microtiter plate. Include a well with 40 &#956;l 45% (w/v) perchloric acid as the blank.</li>
	<li>Add 50 &#956;l of iodine solution (2 g KI + 1 g I2&#160;in 900 ml of ultra-pure water) and mix each sample (including the blank) by pipetting.</li>
	<li>Read absorbances at 550 nm and 620 nm immediately and calculate the amylose/ amylopectin ratio for each concentration.</li>
</ol>

<ol>
	<li>Composition Hoover, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=molecular+structure,+and+physicochemical+properties+of+tuber+and+root+starches:+a+review.">molecular structure, and physicochemical properties of tuber and root starches: a review.</a> Carbohydr. 45 (3), 253-267 (2001).</li><li>Bertoft, E., Blennow, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+Potato+Starch.">Structure of Potato Starch.</a> Advances in Potato Chemistry and Technology. , 83-98 (2009).</li><li>Campbell, M. R., Yeager, H., Abdubek, N., Pollak, L., Glover, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+methods+for+amylose+screening+in+maize+starches+from+exotic+backgrounds.">Comparison of methods for amylose screening in maize starches from exotic backgrounds.</a> Cereal Chem. 79, 317-321 (2002).</li><li>Zhu, T., Jackson, D. S., Wehling, R. L., Geera, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+amylose+determination+methods+and+the+development+of+a+dual+wavelength+iodine+binding+technique.">Comparison of amylose determination methods and the development of a dual wavelength iodine binding technique.</a> Cereal Chem. 85, 51-58 (2008).</li><li>Hovenkamp-Hermelink, J., Devries, J., Adamse, P., Jacobsen, E., Witholt, B., Feenstra, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+estimation+of+the+amylose+amylopectin+ratio+in+small+amounts+of+tuber+and+leaf+tissue+of+the+potato.">Rapid estimation of the amylose amylopectin ratio in small amounts of tuber and leaf tissue of the potato.</a> Potato Res. 31, 241-246 (1988).</li><li>Shannon, J. C., Garwood, D. L., Boyer, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+and+Physiology+of+Starch+Development.">Genetics and Physiology of Starch Development.</a> Starch. , 23-82 (2009).</li><li>Haase, N. U., Plate, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Properties+of+potato+starch+in+relation+to+varieties+and+environmental+factors.">Properties of potato starch in relation to varieties and environmental factors.</a> St&#228;rke. 48 (5), 167-171 (1996).</li><li>Johnston, F. B., Urbas, B., Khanzada, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+storage+on+the+size+distribution+and+amylose/amylopectin+ratio+in+potato+starch+granules.">Effect of storage on the size distribution and amylose/amylopectin ratio in potato starch granules.</a> Am. Pot. J. 45, 315-321 (1968).</li><li>Gibson, T. S., Solah, V. A., McCleary, B. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+procedure+to+measure+amylose+in+cereal+starches+and+flours+with+concanavalin+A.">A procedure to measure amylose in cereal starches and flours with concanavalin A.</a> J. Cereal Sci. 25 (2), 111-119 (1997).</li><li>Sun, S., Matheson, N., Yun, S. -. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+amylose+content+of+starches+after+precipitation+of+amylopectin+by+concanavalin+A.">Estimation of amylose content of starches after precipitation of amylopectin by concanavalin A.</a> Starch. 42, 302-305 (1990).</li></ol>

We have nothing to disclose.

Amylose content in potato tubers typically ranges from 20-35%7,8. If most values are outside this range, consider these possible errors: 1) raw data were used instead of blanked data for the construction of the amylose/amylopectin standard curve; 2) raw data were used instead of blanked data for the determination of the amylose/amylopectin ratios from the potato samples; or 3) the water used for the analysis was not pure enough. We noticed that by using distilled water and not ultra-pure water in the analysis,...

Approximately 80% of the fresh weight of a potato tuber is water; nearly all of the remaining dry matter is starch1. Most of the starch (70%) is composed of amylopectin, while the remainder is amylose. The ratio between amylose and amylopectin is the most important property influencing the physical properties of starch. Amylose is a linear alpha 1-4 glucose chain, while amylopectin is a linear alpha 1-4 chain with alpha 1-6 branches2. Methods such as iodine binding, differential scanning calorimetry (DSC), high performance size exclusion chromatography (HPSEC) and concanavalin A interactions have been developed for starch determination in different crop species3,4. Each protocol requires special skills and equipment, making it difficult to scale up to quantify numerous samples at a time. The method we present here is a modified protocol from Hovenkamp-Hermelink et al.5 which is a dual wavelength iodine binding method based on stained starch granules. The advantages of this method versus others include the amylose determination from raw starch without purifying it and the use of the dual wavelength system to increase the precision of the method4,6.&#160;

<table border="1">
<tbody>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td> Reagents</td>
 </tr>
 <tr>
 <td>Amylose </td>
 <td>Sigma</td>
 <td>859656</td>
 <td></td>
 </tr>
 <tr>
 <td>Amylopectin </td>
 <td>Sigma</td>
 <td>A8515</td>
 <td></td>
 </tr>
 <tr>
 <td>Perchloric Acid 60%</td>
 <td>Sigma</td>
 <td>311413</td>
 <td>Very hazardous to skin and eyes</td>
 </tr>
 <tr>
 <td>Iodine</td>
 <td>Sigma</td>
 <td>23214TD</td>
 <td></td>
 </tr>
 <tr>
 <td>Potassium iodide</td>
 <td>Sigma</td>
 <td>08625JE</td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>Equipment</td>
 </tr>
 <tr>
 <td>Plate Reader</td>
 <td>Bio Tek</td>
 <td>ELx800</td>
 <td></td>
 </tr>
 </tbody>
</table>

rapid high throughput amylose determination in freeze dried potato tuber samples

This protocol describes a high through put colorimetric method that relies on the formation of a complex between iodine and chains of glucose molecules in starch. Iodine forms complexes with both amylose and long chains within amylopectin. After the addition of iodine to a starch sample, the maximum absorption of amylose and amylopectin occurs at 620 and 550 nm, respectively. The amylose/amylopectin ratio can be estimated from the ratio of the 620 and 550 nm absorbance values and comparing them to a standard curve in which specific known concentrations are plotted against absorption values. This high throughput, inexpensive method is reliable and reproducible, allowing the evaluation of large populations of potato clones.&#160;

The standard curve constructed from blanked data of different amylose/amylopectin concentration solutions shows approximate absorbance ratios ranging from 0.7 to 1.6 (Table 1). A linear regression trend line from these data is later used for inferring amylose content in freeze dried potato samples (Figure 1).
The plant production environment has some effect on the amylose content in the potato tuber7. Replicated amylose content determinations in two...

Watch this Scientific Journal Video about Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples at JoVE.com

Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples

This protocol describes a high through put colorimetric method that relies on the formation of a complex between iodine and chains of glucose molecules in ...

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13.8K Views.  University of Wisconsin - Madison. This protocol describes a high through put colorimetric method that relies on the formation of a complex between iodine and chains of glucose molecules in starch. Iodine forms complexes with both amylose and long chains within amylopectin. After the addition of iodine to a starch sample, the maximum absorption of amylose and amylopectin occurs at 620 and 550 nm, respectively. The amylose/amylopectin ratio can be estimated from the ratio of the 620 and 550 nm absorbance va...

Video: Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples

Rapid Colorimetric Assays to Qualitatively Distinguish RNA and DNA in Biomolecular Samples

Biochemical experimentation generally requires accurate knowledge, at an early stage, of the nucleic acid, protein, and other biomolecular components in potentially heterogeneous specimens. Nucleic acids can be detected via several established approaches, including analytical methods that are spectrophotometric (e.g., A260), fluorometric (e.g., binding of fluorescent dyes), or colorimetric (nucleoside-specific chromogenic chemical reactions).1 Though it cannot readily distinguish RNA from DNA, the A260/A280 ratio is commonly employed, as it offers a simple and rapid2 assessment of the relative content of nucleic acid, which absorbs predominantly near 260 nm and protein, which absorbs primarily near 280 nm. Ratios &lt; 0.8 are taken as indicative of 'pure' protein specimens, while pure nucleic acid (NA) is characterized by ratios &gt; 1.53.
However, there are scenarios in which the protein/NA content cannot be as clearly or reliably inferred from simple uv-vis spectrophotometric measurements. For instance, (i) samples may contain one or more proteins which are relatively devoid of the aromatic amino acids responsible for absorption at &asymp;280 nm (Trp, Tyr, Phe), as is the case with some small RNA-binding proteins, and (ii) samples can exhibit intermediate A260/A280 ratios (~0.8 &lt; ~1.5), where the protein/NA content is far less clear and may even reflect some high-affinity association between the protein and NA components. For such scenarios, we describe herein a suite of colorimetric assays to rapidly distinguish RNA, DNA, and reducing sugars in a potentially mixed sample of biomolecules. The methods rely on the differential sensitivity of pentoses and other carbohydrates to Benedict's, Bial's (orcinol), and Dische's (diphenylamine) reagents; the streamlined protocols can be completed in a matter of minutes, without any additional steps of having to isolate the components. The assays can be performed in parallel to differentiate between RNA and DNA, as well as indicate the presence of free reducing sugars such as glucose, fructose, and ribose (Figure 1).

A suite of colorimetric assays is described for rapidly distinguishing protein, RNA, DNA, and reducing sugars in potentially heterogeneous biomolecular samples.

Biochemical experimentation generally requires accurate knowledge, at an early stage, of the nucleic acid, protein, and other biomolecular components in ...

A High-throughput-compatible FRET-based Platform for Identification and Characterization of Botulinum Neurotoxin Light Chain Modulators

Botulinum neurotoxin (BoNT) is a potent and potentially lethal bacterial toxin that binds to host motor neurons, is internalized into the cell, and cleaves intracellular proteins that are essential for neurotransmitter release. BoNT is comprised of a heavy chain (HC), which mediates host cell binding and internalization, and a light chain (LC), which cleaves intracellular host proteins essential for acetylcholine release. While therapies that inhibit toxin binding/internalization have a small time window of administration, compounds that target intracellular LC activity have a much larger time window of administrations, particularly relevant given the extremely long half-life of the toxin. In recent years, small molecules have been heavily analyzed as potential LC inhibitors based on their increased cellular permeability relative to larger therapeutics (peptides, aptamers, etc.). Lead identification often involves high-throughput screening (HTS), where large libraries of small molecules are screened based on their ability to modulate therapeutic target function. Here we describe a FRET-based assay with a commercial BoNT/A LC substrate and recombinant LC that can be automated for HTS of potential BoNT inhibitors. Moreover, we describe a manual technique that can be used for follow-up secondary screening, or for comparing the potency of several candidate compounds.

The botulinum neurotoxin type A light chain (BoNT/A LC) is a metalloprotease that enters motor neurons, cleaves its substrate SNAP-25, and disrupts neurotransmission, thereby resulting in flaccid paralysis. Utilizing a high-throughput-compatible FRET-based assay, large libraries of small molecules can be screened for their impact on BoNT/A LC enzymatic activity.

Botulinum neurotoxin (BoNT) is a potent and potentially lethal bacterial toxin that binds to host motor neurons, is internalized into the cell, and ...

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 ...

Rapid High-throughput Species Identification of Botanical Material Using Direct Analysis in Real Time High Resolution Mass Spectrometry

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, and that these chemical fingerprints can be used for plant species identification. The mass spectral data can be acquired rapidly and in a high throughput manner without the need for sample extraction, derivatization or pH adjustment steps. The use of this technique bypasses challenges presented by more conventional techniques including lengthy chromatography analysis times and resource intensive methods. The high throughput capabilities of the direct analysis in real time-high resolution mass spectrometry protocol, coupled with multivariate statistical analysis processing of the data, provide not only class characterization of plants, but also yield species and varietal information. Here, the technique is demonstrated with two psychoactive plant products, Mitragyna speciosa (Kratom) and Datura (Jimsonweed), which were subjected to direct analysis in real time-high resolution mass spectrometry followed by statistical analysis processing of the mass spectral data. The application of these tools in tandem enabled the plant materials to be rapidly identified at the level of variety and species.

A method for species identification of botanical material by direct analysis in real time-high resolution mass spectrometry and multivariate statistical analysis is presented.

We demonstrate that direct analysis in real time-high resolution mass spectrometry can be used to produce mass spectral profiles of botanical material, ...

Extraction and Purification of Polyphenols from Freeze-dried Berry Powder for the Treatment of Vascular Smooth Muscle Cells In Vitro

Epidemiological studies indicate that increased flavonoid intake correlates with decreased mortality due to cardiovascular diseases (CVD) in the United States (US) and Europe. Berries are widely consumed in the US and have a high polyphenolic content. Polyphenols have been shown to interact with many molecular targets and to exert numerous positive biological functions, including antioxidant, anti-inflammatory, and cardioprotective effects. Polyphenols isolated from blackberry (BL), raspberry (RB), and black raspberry (BRB) reduce oxidative stress and cellular senescence in response to angiotensin II (Ang II). This work provides a detailed description of the protocol used to prepare the polyphenol extracts from freeze-dried berries. Polyphenol extractions from freeze-dried berry powder were performed using 80% aqueous ethanol and an ultrasonic-assisted extraction method. The crude extract was further purified and fractionated using chloroform and ethyl acetate, respectively. The effects of both crude and purified extracts were tested on Vascular Smooth Muscle Cells (VSMCs) in culture.

Extraction and Purification of Polyphenols from Freeze-dried Berry Powder for the Treatment of Vascular Smooth Muscle Cells In Vitro

This work details a step-by-step method to prepare polyphenol-rich extracts from freeze-dried berry powder. In addition, it provides a thorough description of how to use these polyphenol-rich extracts in cell culture in the presence of the peptide hormone angiotensin II (Ang II) using Vascular Smooth Muscle Cells (VSMCs).

Epidemiological studies indicate that increased flavonoid intake correlates with decreased mortality due to cardiovascular diseases (CVD) in the United ...

Disentangling High Strength Copolymer Aramid Fibers to Enable the Determination of Their Mechanical Properties

Traditionally, soft body armor has been made from poly(p-phenylene terephthalamide) (PPTA) and ultra-high molecular weight polyethylene. However, to diversify the fiber choices in the United States body armor market, copolymer fibers based on the combination of 5-amino-2-(p-aminophenyl) benzimidazole (PBIA) and the more conventional PPTA were introduced. Little is known regarding the long-term stability of these fibers, but as condensation polymers, they are expected to have potential sensitivity to moisture and humidity. Therefore, characterizing the strength of the materials and understanding their vulnerability to environmental conditions is important for evaluating their use lifetime in safety applications. Ballistic resistance and other critical structural properties of these fibers are predicated on their strength. To accurately determine the strength of the individual fibers, it is necessary to disentangle them from the yarn without introducing any damage. Three aramid-based copolymer fibers were selected for the study. The fibers were washed with acetone followed by methanol to remove an organic coating that held the individual fibers in each yarn bundle together. This coating makes it difficult to separate single fibers from the yarn bundle for mechanical testing without damaging the fibers and affecting their strength. After washing, fourier transform infrared (FTIR) spectroscopy was performed on both washed and unwashed samples and the results were compared. This experiment has shown that there are no significant variations in the spectra of poly(p-phenylene-benzimidazole-terephthalamide-co-p-phenylene terephthalamide) (PBIA-co-PPTA1) and PBIA-co-PPTA3 after washing, and only a small variation in intensity for PBIA. This indicates that the acetone and methanol rinses are not adversely affecting the fibers and causing chemical degradation. Additionally, single fiber tensile testing was performed on the washed fibers to characterize their initial tensile strength and strain to failure, and compare those to other reported values. Iterative procedural development was necessary to find a successful method for performing tensile testing on these fibers.

The primary goal of the study is to develop a protocol to prepare consistent specimens for accurate mechanical testing of high strength copolymer aramid fibers, by removing a coating and disentangling the individual fiber strands without introducing significant chemical or physical degradation.

Traditionally, soft body armor has been made from poly(p-phenylene terephthalamide) (PPTA) and ultra-high molecular weight polyethylene. However, to ...

High-throughput and Comprehensive Drug Surveillance Using Multisegment Injection-Capillary Electrophoresis-Mass Spectrometry

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug crisis in public health. Conventional urine drug testing based on a two-tier immunoassay screen followed by a gas chromatography-tandem mass spectrometry (GC-MS/MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) method are expensive and prone to bias while being limited to targeted panels of known drugs of abuse (DoA). Herein, we outline an improved method for drug surveillance that allows for the resolution and detection of an expanded panel of DoA and their metabolites when using multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). Multiplexed separations of ten urine samples with a quality control by CE (&lt; 3 min/sample) in conjunction with full-scan data acquisition using a time-of-flight mass spectrometer (TOF-MS) under positive ion mode detection allows for the identification and quantification of DoA above recommended cut-off levels. An excellent resolution of drug isomers and isobars, including background interferences, are achieved when using MSI-CE-MS with an electrokinetic spacer between sample segments, where accurate mass/molecular formula together with the comigration of a matching deuterated internal standard and the detection of one or more bio-transformed metabolites facilitate DoA identification over a wider detection window. Additionally, urine samples can be analyzed directly without enzyme deconjugation for the rapid screening without complicated sample workup. MSI-CE-MS enables the surveillance of a broad spectrum of DoA that is required for the treatment monitoring of high-risk patients, including confirming prescribed drug adherence, revealing illicit drug use/substitution, and evaluating optimal dosage regimes as required for new advances in precision medicine.

Here we describe a high-throughput method for comprehensive drug surveillance that allows for the improved resolution and detection of large panels of drugs of abuse and their metabolites, with quality control based on multisegment injection-capillary electrophoresis-mass spectrometry.

New analytical methods are urgently needed to enable high-throughput, yet comprehensive drug screening, given an alarming opioid and prescription drug ...

Biological Samples Preparation for Speciation at Cryogenic Temperature using High-Resolution  X-Ray Absorption Spectroscopy

The study of elements with X-ray absorption spectroscopy (XAS) is of particular interest when studying the role of metals in biological systems. Sample preparation is a key and often complex procedure, particularly for biological samples. Although X-ray speciation techniques are widely used, no detailed protocol has been yet disseminated for users of the technique. Further, chemical state modification is of concern, and cryo-based techniques are recommended to analyze the biological samples in their near-native hydrated state to provide the maximum preservation of chemical integrity of the cells or tissues. Here, we propose a cellular preparation protocol based on cryo-preserved samples. It is demonstrated in a high energy resolution fluorescence detected X-ray absorption spectroscopy study of selenium in cancer cells and a study of iron in phytoplankton. This protocol can be used with other biological samples and other X-ray techniques that can be damaged by irradiation.

This protocol presents a detailed procedure to prepare biological cryosamples for synchrotron-based X-ray absorption spectroscopy experiments. We describe all the steps required to optimize sample preparation and cryopreservation with examples of the protocol with cancer and phytoplankton cells. This method provides a universal standard of sample cryo-preparation.

The study of elements with X-ray absorption spectroscopy (XAS) is of particular interest when studying the role of metals in biological systems. Sample ...

An Externally-Heated Diamond Anvil Cell for Synthesis and Single-Crystal Elasticity Determination of Ice-VII at High Pressure-Temperature Conditions

The externally-heated diamond anvil cell (EHDAC) can be used to generate simultaneously high-pressure and high-temperature conditions found in Earth&#8217;s and planetary interiors. Here we describe the design and fabrication of the EHDAC assemblies and accessories, including ring resistive heaters, thermal and electrical insulating layers, thermocouple placement, as well as the experimental protocol for preparing the EHDAC using these parts. The EHDAC can be routinely used to generate megabar pressures and up to 900 K temperatures in open air, and potentially higher temperatures up to ~1200 K with a protective atmosphere (i.e., Ar mixed with 1% H2). Compared with a laser-heating method for reaching temperatures typically &#62;1100 K, external heating can be easily implemented and provide a more stable temperature at &#8804;900 K and less temperature gradients to the sample. We showcased the application of the EHDAC for synthesis of single crystal ice-VII and studied its single-crystal elastic properties using synchrotron-based X-ray diffraction and Brillouin scattering at simultaneously high-pressure high-temperature conditions.

This work focuses on the standard protocol for preparing the externally-heated diamond anvil cell (EHDAC) for generating high-pressure and high-temperature (HPHT) conditions. The EHDAC is employed to investigate materials in Earth and planetary interiors under extreme conditions, which can be also used in solid state physics and chemistry studies.

The externally-heated diamond anvil cell (EHDAC) can be used to generate simultaneously high-pressure and high-temperature conditions found in ...

Synthesis and Discovery of Phosphonate-Based MOFs: A Solvothermal Approach

Discovery and Synthesis Optimization of Isoreticular Al(III) Phosphonate-Based Metal-Organic Framework Compounds Using High-Throughput Methods

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This manuscript describes the synthesis of metal-organic frameworks (MOFs) from solution using an HT reactor system, resulting in the discovery of various phosphonate-based MOFs of the composition [Al2H12-x(PMP)3]Clx&#8729;6H2O (H4PMP = N,N &#39;-piperazine bis(methylenephosphonic acid)) for x = 4, 6, denoted as Al-CAU-60-xHCl, containing trivalent aluminum ions. This was accomplished under solvothermal reaction conditions by systematically screening the impact of the molar ratio of the linker to the metal and the pH of the reaction mixture on the product formation. The protocol for the HT investigation includes six steps: a) synthesis planning (DOE = design of&#160;experiment) within the HT methodology, b) dosing and working with in-house developed HT reactors, c) solvothermal synthesis, d) synthesis workup using in-house developed filtration blocks, e) characterization by HT powder X-ray diffraction, and f) evaluation of the data. The HT methodology was first used to study the influence of acidity on the product formation, leading to the discovery of Al-CAU-60&#8729;xHCl (x = 4 or 6).

Author Spotlight: Accelerating Discovery in Microporous Material Chemistry 

The targeted synthesis of new metal-organic frameworks (MOFs) is difficult, and their discovery depends on the knowledge and creativity of the chemist. High-throughput methods allow complex synthetic parameter fields to be explored quickly and efficiently, accelerating the process of finding crystalline compounds and identifying synthetic and structural trends.

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This ...