The authors would like to aknowledge the colleagues and people involved in the different steps of the project. The colleagues in the JRC Karlsruhe design office, Messrs. Dietrich Knoche and Volkmar Ernest, in the JRC Karlsruhe Workshop Messrs. Christian Diebold and Joachim K&#252;st for the design and manufacturing of the lab on valve (LOV) manifold and Ringwald GmbH for the software implementation of the stopped-flow detection mode technique.

Note: Solutions were prepared from high-purity water (18.2 M&#937; cm) using devices designed for ultratrace analysis. Nitric acid was purified using a quartz sub-boiling distillation unit. Both the water purification system and the sub-boiling distillation unit were operated in a clean room.
Caution: 90Sr is acutely toxic and carcinogenic. Appropriate safety practices are essential when performing the experiments, including both engineering control systems and personal protective equipment.
1. Experiment Preparation
Note: A detailed description regarding the software architecture and its functionalities can be found elsewhere23.
<ol>
	<li>Connect the Modular Valve Position exit port to the entry port of the radio flow detector.</li>
	<li>Connect the Trigger line to selected detector.</li>
	<li>Ensure that the LOV ports are properly connected. Ensure that adequate volumes of working solutions are available for the entire protocol and that liquid sampling tubing will remain submerged.</li>
	<li>Ensure that the Autosampler is on, start the autosampler software, and via the software interface, initialize the autosampler. Click the Initialize button to generate the communication between the apparatus and the PC.</li>
	<li>Ensure the AutoRAD software has been started, check the communication ports using the options tab and initialize the software via the user interface. Refer to Discussion section for more details regarding the software graphical interface.</li>
	<li>Ensure that the analysis sequence is programmed in the detector Software. Program vew sequences using the Method editor tab in the AutoRAD software, by entering the number of steps needed and the tasks and speed for each device. 
	Note: A detailed description of the software operation can be found in previous publication23.</li>
	<li>Consult the local radioprotection officer and employ the radioprotection measurements needed for the complete procedure using 90Sr.</li>
</ol>
2. System Cleaning
<ol>
	<li>Load 10 mL of 18.2 M&#937; cm water from the flask to the syringe at 90 mL&#183;min-1. Ensure that the syringe valve position is set to the In position for this step. In this position, loading occurs directly to the syringe and not through the LOV.</li>
	<li>Drop the water to the waste via the holding coil at a flow rate of 90 mL&#183;min-1.</li>
	<li>Load 3 mL of ethanol to the holding coil at a flow rate of 3 mL&#183;min-1. Set the syringe valve position to Out.</li>
	<li>Drop the ethanol to the detector coil at a flow rate of 3 mL&#183;min-1.</li>
</ol>
3. Load Resin to the LOV
<ol>
	<li>While stirring the resin suspension in water (12 mg&#183;mL-1), pick up 3 mL via the LOV. Set the flow to 3 mL&#183;min-1</li>
	<li>Drop the resin suspension into the column channel at a flow rate of 1.2 mL&#183;min-1</li>
	<li>Clean the holding coil and drop the resin residues onto the column channel. For this, load 9 mL of 18.2 M&#937; cm water from the flask to the syringe at a flow rate of 90 mL&#183;min-1. Ensure that the syringe valve position is in the In position. Drop the water to the waste via the holding coil at a flow rate of 3 mL&#183;min-1.</li>
</ol>
4. Analysis Sequence
<ol>
	<li>Column conditioning
	<ol>
		<li>Load 2 mL of HNO3 (4 M) via the LOV to the holding coil. Set the flow to 6 mL&#183;min-1.</li>
		<li>Drop the HNO3 onto the column at a flow rate of 1.2 mL&#183;min-1.</li>
	</ol>
	</li>
	<li>Sample loading and elimination of interferences
	<ol>
		<li>Load sample (1.3 mL) from the autosampler to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Drop the sample onto the column at a flow rate of 1.2 mL&#183;min-1.</li>
		<li>Load 0.5 mL of HNO3 (4 M) to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Rinse the column with 0.5 mL of HNO3 (4 M) to elute matrix interferences at a flow rate of 1.2 mL&#183;min-1.</li>
	</ol>
	</li>
	<li>Elution of the sample and measurement
	<ol>
		<li>Load 5 mL of 18.2 M&#937; cm water to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Trigger the detector. Set the flow rate of the scintillation liquid to 2 mL&#183;min-1 in the detector software. Set the dwell to 10 s. The sample coil has a volume of 2 mL.</li>
		<li>Rinse the column.</li>
	</ol>
	</li>
	<li>rinsing of the sample probe and holding coil
	<ol>
		<li>Load 0.6 mL of HNO3 (1%) to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Load 0.6 mL of air to the holding coil at a flow rate of 6 mL&#183;min-1.</li>
		<li>Discharge 1.2 mL of the mixture to the waste.</li>
	</ol>
	</li>
	<li>Resin replacement
	<ol>
		<li>Load 0.2 mL of ethanol to the holding coil at a flow rate of 3 mL&#183;min-1.</li>
		<li>Rinse the column with 0.2 mL of ethanol at a flow rate of 1.2 mL&#183;min-1.</li>
		<li>Flush the column channel with 0.5 mL of water at a flow rate of 0.45 mL&#183;min-1.</li>
		<li>Discharge the used resin to the waste.</li>
	</ol>
	</li>
</ol>

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H., 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=Rapid+determination+of+radiostrontium+in+milk+using+automated+radionuclides+separator+and+liquid+scintillation+counter.">Rapid determination of radiostrontium in milk using automated radionuclides separator and liquid scintillation counter.</a> Journal of Radioanalytical and Nuclear Chemistry. 304 (1), 293-300 (2015).</li><li>Desmartin, P., Kopajtic, Z., Haerdi, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiostrontium-90+(90Sr)+Ultra-Traces+Measurements+by+Coupling+Ionic+Chromatography+(HPIC)+and+on+Line+Liquid+Scintillation+Counting+(OLLSC).">Radiostrontium-90 (90Sr) Ultra-Traces Measurements by Coupling Ionic Chromatography (HPIC) and on Line Liquid Scintillation Counting (OLLSC).</a> Environmental Monitoring and Assessment. 44 (1), 413-423 (1997).</li><li>Grate, J. 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O., Cerd&#224;, V., Ferrer, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+for+automating+solid-phase+extraction+and+liquid-liquid+extraction+in+radiochemical+analysis.">Strategies for automating solid-phase extraction and liquid-liquid extraction in radiochemical analysis.</a> TrAC Trends in Analytical Chemistry. 76, 145-152 (2016).</li><li>Mir&#243;, M., Oliveira, H. M., Segundo, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analytical+potential+of+mesofluidic+lab-on-a-valve+as+a+front+end+to+column-separation+systems.">Analytical potential of mesofluidic lab-on-a-valve as a front end to column-separation systems.</a> TrAC Trends in Analytical Chemistry. 30 (1), 153-164 (2011).</li><li>Ko&#322;aci&#324;ska, 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=Automation+of+sample+processing+for+ICP-MS+determination+of+90Sr+radionuclide+at+ppq+level+for+nuclear+technology+and+environmental+purposes.">Automation of sample processing for ICP-MS determination of 90Sr radionuclide at ppq level for nuclear technology and environmental purposes.</a> Talanta. , (2016).</li><li>Rodr&#237;guez, R., Avivar, J., Ferrer, L., Leal, L. O., Cerd&#224;, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Automated+total+and+radioactive+strontium+separation+and+preconcentration+in+samples+of+environmental+interest+exploiting+a+lab-on-valve+system.">Automated total and radioactive strontium separation and preconcentration in samples of environmental interest exploiting a lab-on-valve system.</a> Talanta. 96, 96-101 (2012).</li><li>Rodr&#237;guez, R., 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=Automation+of+99Tc+extraction+by+LOV+prior+ICP-MS+detection:+Application+to+environmental+samples.">Automation of 99Tc extraction by LOV prior ICP-MS detection: Application to environmental samples.</a> Talanta. 133, 88-93 (2015).</li><li>Villar, 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=Automatic+and+Simple+Method+for+99Tc+Determination+Using+a+Selective+Resin+and+Liquid+Scintillation+Detection+Applied+to+Urine+Samples.">Automatic and Simple Method for 99Tc Determination Using a Selective Resin and Liquid Scintillation Detection Applied to Urine Samples.</a> Analytical Chemistry. 85 (11), 5491-5498 (2013).</li><li>L'Annunziata, M. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Radioactivity Analysis. , 1117-1178 (2012).</li><li>Roane, J. E., DeVol, T. A., Leyba, J. D., Fjeld, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+extraction+chromatography+resins+to+concentrate+actinides+and+strontium+from+soil+for+radiochromatographic+analyses.">The use of extraction chromatography resins to concentrate actinides and strontium from soil for radiochromatographic analyses.</a> Journal of Environmental Radioactivity. 66 (3), 227-245 (2003).</li><li>Barbesi, D., 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=A+LabVIEW&#174;-based+software+for+the+control+of+the+AUTORAD+platform:+a+fully+automated+multisequential+flow+injection+analysis+Lab-on-Valve+(MSFIA-LOV)+system+for+radiochemical+analysis.">A LabVIEW&#174;-based software for the control of the AUTORAD platform: a fully automated multisequential flow injection analysis Lab-on-Valve (MSFIA-LOV) system for radiochemical analysis.</a> Journal of Radioanalytical and Nuclear Chemistry. 313 (1), 217-227 (2017).</li><li>Barbesi, D., 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=A+LabVIEW&#174;-based+software+for+the+control+of+the+AUTORAD+platform:+a+fully+automated+multisequential+flow+injection+analysis+Lab-on-Valve+(MSFIA-LOV)+system+for+radiochemical+analysis.">A LabVIEW&#174;-based software for the control of the AUTORAD platform: a fully automated multisequential flow injection analysis Lab-on-Valve (MSFIA-LOV) system for radiochemical analysis.</a> Journal of Radioanalytical and Nuclear. , 1-11 (2017).</li><li>Strahlenschutz, F. f. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Moderne Routine- und Schnellmethoden zur Bestimmung von SR-89 und SR-90 bei der Umwelt&#252;berwachung : Bericht einer Ad-hoc-Arbeitsgruppe des Arbeitskreises Umwelt&#252;berwachung (AKU). , (2008).</li><li>Currie, L. 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The authors have nothing to disclose.

Radiological characterization and protection are critical issues during all phases of a nuclear facility life cycle. The need for radionuclide determination during the decommissioning of nuclear facilities requires continuous improvement of analytical procedures. This entails the enhancement of selectivity and sensitivity, and shortening the analysis time . The AUTORAD prototype fulfils these requirements. In addition, the prototype is portable and allows on-site determination. The proposed automated on-line method was successfully applied for the determination of 90Sr activity in aqueous samples.
Figure 1 shows a schematic diagram of the AutoRAD system. Communication with the prototype was achieved using the commercial graphical programming language LabVIEW 2014. The Virtual Instrument Software Architecture (VISA) mode for configuring, programming and controlling interfaces was deployed. Figure 2 shows the graphical user interface screen where the port configuration can be verified prior to system initialization. The VISA mode is independent on the operating system and program environment, so it provides exceptional versatility. The basic structure and features of the developed software have been widely discussed in previous publication24. Improvements have been achieved by controlling the burettes by the PC using an RS232 interface, thus allowing enhanced control of both burettes simultaneously and the possibility to perform measurements in stop flow mode. In contrast, the RS232 connection reacts quickly when the system backpressure increases. This can lead to system error and measurement stop. Therefore, special attention has to be paid in the process of resin loading and ionic strength of the samples.
The optimization of the experimental conditions was achieved in a set of experiments using the strontium stable isotope 86Sr as a surrogate for the radioactive 90Sr, and by coupling the AUTORAD system to an ICP-MS rather than a beta detctcor system. Figure 3 shows the ICP-MS 86Sr elution profiles. The obtained 86Sr elution profiles are in full agreement with previously reported results for total strontium using low pressure separation devices25, and have been blank subtracted. The least squares linear regression method was used to generate a fit for the purpose curve which does not introduce an extra uncertainty component. The linearity obtained was 0.995, with p-values less than the significance level. The LOD of 2 pg&#183;g-1was determined by repeated measurements of the blank according to Currie26. The reproducibility of the method, based on the relative standard deviation of the peak area calculated on the basis of three repeated runs, was always less than 4% in the range of 10 to 120 pg&#183;g-1. The shoulder witnessed in the elution profiles is most likely an artefact due to non-optimal packing of the column in the automated AUTORAD configuration.
Figure 4 shows the 90Sr profile using the the radio flow detector. The AUTORAD system is able to effectively separate 90Sr in aqueous samples.
Figure 5 shows the dependence of the 90Sr concentration with the signal is linear in the range of interest. The derived detection limit is in the fg. g-1 range, enabling, without further modification, the determination of radiostrontium in nuclear decommissioning and waste characterization samples. Reproducibility of the method, using the flow scintillation detector and based on the relative standard deviation of the peak area, is around 30% in the studied concentration range. The current set-up of the prototype, however, limits its application to environmental samples, essentially due to the short time counting in the detector. Furthermore, complex matrices might saturate the resin in the mini column.
The stopped-flow technique, where both Hamilton and radio flow detector pump are stopped during the measurement, will be implemented. This feature will improve the sensitivity by extending the residence time in the largest part of the sample zone within the flow cell. Thus, a statistically meaningful signal is acculated before the sample exits the detector. This approach will improve both the counting statistics and the detection limits. In addition, a new application is being developed including an additional ion-exchange mini-column for the removal of matrix components that could affect the retention and separation of different radionuclides in complex matric samples.

About 150 commercial nuclear power plants (NPP) are undergoing decommissioning, but the total number of nuclear facilities is much greater if research and reprocessing facilities are taken into consideration1. Decommissioning of nuclear facilities is very costly and involves transport and off site measurement of contaminated material. Savings are possible by adopting on-site and flexible measurement techniques1. There is therefore an urgent need for rapid on site analytical methods supporting the decommissioning of old nuclear facilities. Gamma-emitters can be easily and selectively determined using gamma-spectroscopy, but there is a deficiency in on-site analytical methods for the hard-to-measure (HTM) radionuclides2. Among the HTM, 90Sr is of great interest due to its toxicity and high energy emission. Its determination is time consuming and requires the separation from interferences and quantification using LSC or spectroscopic methods3,4,5,6,7,8,9,10,11,12,13.
Standard radiochemical methods are time-consuming and often require repetitions to obtain an adequate yield of strontium. Therefore, there is an urgent need for faster and accurate methods. Besides the standard separation protocols, flow injection techniques are applied in the purification and/or pre-concentration of radioisotopes5,14,15. Lab-on-Valve (LOV) devices are a further development in flow techniques. They are programmable, flow-based platforms with different coupling modes and exhibit high versatility16. Such devices allow the automatic separation and pre-concentration of the analytes prior to the detection, thus increasing reproducibility and repeatability8,17,18,19. LOV systems coupled to multisyringe flow pumps have been widely used for the detection of radionuclides, due to the minimization of the reagent consumption and waste generation8,10,17,18,19,20. Nevertheless, reported studies regarding online detection at ultra-trace levels are sparse8,17.
On-site measurements of radioactive materials have many benefits and advantages, but there is no application of flow scintillation to 90Sr monitoring. Basically, quantification is achieved using an online detector that mixes the eluate coming from the LOV device with the scintillating cocktail11,21,22. The mixture is then pumped through the counting cell and measurement is made using paired photomultipliers. Due to the small volume of the cell, the measurement time is in the seconds scale.
The aim of this research is the development of a fully automated method for on-line strontium detection over a large working range, covering both environmentally relevant concentrations and also those found in nuclear industry waste streams. The platform is mobile and can be mounted in a vehicle to perform on-site analysis of aqueous samples.

<table>
	<tbody>
		<tr>
			<td>microLAB 600 series</td>
			<td>Hamilton</td>
			<td>ML600EE6910</td>
			<td>Two dual syringe pump system, equiped with two 10 mL glass syringes. The instruments are interconnected using the CAN port (daisy chain).&#160;</td>
		</tr>
		<tr>
			<td>FlowLogic U</td>
			<td>LabLogic</td>
			<td>SG-BXX-05</td>
			<td>Liquid scintillator with high flash point</td>
		</tr>
		<tr>
			<td>&#223;-RAM 5&#160;</td>
			<td>LabLogic</td>
			<td></td>
			<td>flow detector, 2000 &#956;L coiled Teflon flow cell.Software&#160; Laura 4.2.8 (LabLogic, England) run on desktop PC and connected to the detector via USB</td>
		</tr>
		<tr>
			<td>SC-&#956; DX Autosampler</td>
			<td>Elemental Scientific Instruments (ESI)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cheminert selector</td>
			<td>Valco Instruments Co. Inc.&#160;</td>
			<td></td>
			<td>in-house made Lab-on-Valve has been mounted on this selector</td>
		</tr>
		<tr>
			<td>Modular Valve 
			Positioner (MVP)</td>
			<td>Hamilton</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>mini magnetic stirrer</td>
			<td>IKA</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nitric Acid Suprapur 65%</td>
			<td>Merck</td>
			<td>1.00441.1000</td>
			<td>purified using quartz sub-boiling distillation unit</td>
		</tr>
		<tr>
			<td>Sr-resin</td>
			<td>Eichchrom Tecnologies, Inc</td>
			<td>SR-B100-A</td>
			<td>particle size 100-150 &#181;m</td>
		</tr>
		<tr>
			<td>Water system Elix 3 in combination with Mili-Q Element A10</td>
			<td>Millipore</td>
			<td></td>
			<td>high-purity water (18.2 M&#937; cm)&#160;</td>
		</tr>
		<tr>
			<td>Sr-90 standard</td>
			<td>Eckert &#38; Ziegler</td>
			<td>7090</td>
			<td>Sr-90 concentration 1.915 kBq/g &#177; 3.0%, reference date 15-May-2016 12:00 PST</td>
		</tr>
		<tr>
			<td>MLS quartz sub-boiling distillation unit</td>
			<td>MLS GmbH</td>
			<td></td>
			<td>Subboiling unit for the purification of HCl and nitric acid</td>
		</tr>
	</tbody>
</table>

automated 90sr separation and preconcentration in a lab-on-valve system at ppq level

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow injection analysis, has been developed. The concentrations of radioactive strontium were determined by flow scintillation counting, allowing for on-line and also on-site determination. The proposed system can determine radioactive strontium at industrial relevant levels without further modification using overall analysis time of less than 10 min per aqueous sample. The limit of the detection is 320 fg&#183;g-1 (1.7 Bq/g).

The fully automated AUTORAD platform operated by homemade LabVIEW-based software has been developed and implemented (Figure 1). The software allows sufficient flexibility for daily operation in a user-friendly environment (Figure 2). The versatility of the platform has been also demonstrated by coupling it to different detectors (Figure 3). The applicability of the method has been demonstrated in aqueous samples spiked with a 90Sr standard (Figure 4). The parameters linearity, linear range, limit of detection (LOD) and repeatability have been evaluated (Figure 5).
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57722/57722fig1.jpg" /> 
Figure 1. Schematic representation of the AutoRAD system showing the port configuration and reagents used. The central port is connected to the syringe pump via the holding coil (10 mL); the methacrylate LOV was fabricated in house. <a href="/files/ftp_upload/57722/57722fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57722/57722fig2.jpg" /> 
Figure 2. AutoRAD Software options menu. The bottom right corner area shows the assigned ports. Via the scroll down menu, the user is able to make changes in the assignment. <a href="/files/ftp_upload/57722/57722fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57722/57722fig3.jpg" /> 
Figure 3. 86Sr elution peaks using an Inductively coupled plasma mass spectrometry (ICP-MS) as a detector. Strontium is eluted quantitatively from the column during the first 100 s of the elution. <a href="/files/ftp_upload/57722/57722fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57722/57722fig4.jpg" /> 
Figure 4. 34.5 &#177; 1 Bq 90Sr (6.6 pg&#183;g-1) elution peak using &#223;-RAM 5 as detector. The residence time in the coil was 40 s. The overall recovery rate of the proposed methodology for 90Sr is 70% &#177; 5%. <a href="/files/ftp_upload/57722/57722fig4large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57722/57722fig5.jpg" /> 
Figure 5. Calibration curve for the count rate versus the concentration of radiostrontium. A good linearity was obtained (R2 = 0.997). The detection limit was calculated as 320 fg&#183;g-1 &#177; 5 (1.7 Bq) by three point three times standard deviation of the blank. <a href="/files/ftp_upload/57722/57722fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level at JoVE.com

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

Here, we present the portable autoRAD platform for quick radiometric separation and determination of 90Sr, an important fission product highly pertinent to nuclear waste.

Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

A quick, automated and portable system for the separation and determination of radiostrontium in aqueous samples, using Sr-resin and multi sequential flow ...

automated-90sr-separation-preconcentration-lab-on-valve-system-at-ppq

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7.9K Views.  European Commission, DG Joint Research Centre - JRC. Here, we present the portable autoRAD platform for quick radiometric separation and determination of 90Sr, an important fission product highly pertinent to nuclear waste.

Video: Automated 90Sr Separation and Preconcentration in a Lab-on-Valve System at Ppq Level

Isolation and Chemical Characterization of Lipid A from Gram-negative Bacteria

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS can be subdivided into three domains: the distal O-polysaccharide, a core oligosaccharide, and the lipid A domain consisting of a lipid A molecular species and 3-deoxy-D-manno-oct-2-ulosonic acid residues (Kdo). The lipid A domain is the only component essential for bacterial cell survival. Following its synthesis, lipid A is chemically modified in response to environmental stresses such as pH or temperature, to promote resistance to antibiotic compounds, and to evade recognition by mediators of the host innate immune response. The following protocol details the small- and large-scale isolation of lipid A from gram-negative bacteria. Isolated material is then chemically characterized by thin layer chromatography (TLC) or mass-spectrometry (MS). In addition to matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS, we also describe tandem MS protocols for analyzing lipid A molecular species using electrospray ionization (ESI) coupled to collision induced dissociation (CID) and newly employed ultraviolet photodissociation (UVPD) methods. Our MS protocols allow for unequivocal determination of chemical structure, paramount to characterization of lipid A molecules that contain unique or novel chemical modifications. We also describe the radioisotopic labeling, and subsequent isolation, of lipid A from bacterial cells for analysis by TLC. Relative to MS-based protocols, TLC provides a more economical and rapid characterization method, but cannot be used to unambiguously assign lipid A chemical structures without the use of standards of known chemical structure. Over the last two decades isolation and characterization of lipid A has led to numerous exciting discoveries that have improved our understanding of the physiology of gram-negative bacteria, mechanisms of antibiotic resistance, the human innate immune response, and have provided many new targets in the development of antibacterial compounds.

Isolation and characterization of the lipid A domain of lipopolysaccharide (LPS) from gram-negative bacteria provides insight into cell surface based mechanisms of antibiotic resistance, bacterial survival and fitness, and how chemically diverse lipid A molecular species differentially modulate host innate immune responses.

Lipopolysaccharide (LPS) is the major cell surface molecule of gram-negative bacteria, deposited on the outer leaflet of the outer membrane bilayer. LPS ...

Synthesis and Exfoliation of Discotic Zirconium Phosphates to Obtain Colloidal Liquid Crystals

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and engineers. Growth of such anisotropic nanocrystals through a simple chemical method is a challenging task. In this study, we fabricate discotic nanodisks of zirconium phosphate [Zr(HPO4)2&#183;H2O] as a model material using hydrothermal, reflux and microwave-assisted methods. Growth of crystals is controlled by duration time, temperature, and concentration of reacting species. The novelty of the adopted methods is that discotic crystals of size ranging from hundred nanometers to few micrometers can be obtained while keeping the polydispersity well within control. The layered discotic crystals are converted to monolayers by exfoliation with tetra-(n)-butyl ammonium hydroxide [(C4H9)4NOH, TBAOH]. Exfoliated disks show isotropic and nematic liquid crystal phases. Size and polydispersity of disk suspensions is highly important in deciding their phase behavior.

A two dimensional model material of discotic zirconium phosphate was developed. The inorganic crystal with lamellar structure was synthesized by hydrothermal, reflux, and microwave-assisted methods. On exfoliation with organic molecules, layered crystals can be converted to monolayers, and nematic liquid crystal phase was formed at sufficient concentration of monolayers.

Due to their abundance in natural clay and potential applications in advanced materials, discotic nanoparticles are of interest to scientists and ...

PTR-ToF-MS Coupled with an Automated Sampling System and Tailored Data Analysis for Food Studies: Bioprocess Monitoring, Screening and Nose-space Analysis

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that belongs to the Direct-Injection Mass Spectrometric (DIMS) technologies. These techniques allow the rapid determination of volatile organic compounds (VOCs), assuring high sensitivity and accuracy. In general, PTR-MS requires neither sample preparation nor sample destruction, allowing real time and non-invasive analysis of samples. PTR-MS are exploited in many fields, from environmental and atmospheric chemistry to medical and biological sciences. More recently, we developed a methodology based on coupling PTR-ToF-MS with an automated sampler and tailored data analysis tools, to increase the degree of automation and, consequently, to enhance the potential of the technique. This approach allowed us to monitor bioprocesses (e.g. enzymatic oxidation, alcoholic fermentation), to screen large sample sets (e.g. different origins, entire germoplasms) and to analyze several experimental modes (e.g. different concentrations of a given ingredient, different intensities of a specific technological parameter) in terms of VOC content. Here, we report the experimental protocols exemplifying different possible applications of our methodology: i.e. the detection of VOCs released during lactic acid fermentation of yogurt (on-line bioprocess monitoring), the monitoring of VOCs associated with different apple cultivars (large-scale screening), and the in vivo study of retronasal VOC release during coffee drinking (nosespace analysis).

Proton Transfer Reaction Time of Flight Mass Spectrometry allows high-sensitivity, rapid and non-invasive analysis of volatile organic compounds. To demonstrate its potential, we give three examples: lactic acid fermentation of yogurt (on-line bioprocess monitoring), different apple genotypes (large-scale screening), and retronasal space after drinking coffee (nosespace analysis).

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that ...

Preparation of Biopolymer Aerogels Using Green Solvents

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).

A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

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, ...

Analyzing the Photo-oxidation of 2-propanol at Indoor Air Level Concentrations Using Field Asymmetric Ion Mobility Spectrometry

We demonstrate a versatile protocol to be used for determining the effectiveness of photocatalysts in degrading indoor air concentration (ppb) volatile organic carbons (VOCs), illustrating this with a titanium dioxide based catalyst, and the VOC 2-propanol. The protocol takes advantage of field asymmetric ion mobility spectroscopy (FAIMS), an analysis tool that is capable of continuously identifying and monitoring the concentration of VOCs such as 2-propanol and acetone at the ppb level. The continuous nature of FAIMS allows detailed kinetic analysis, and long-term reactions, offering a significant advantage over gas chromatography, a batch process traditionally used in air purification characterization. The use of FAIMS in photocatalytic air purification has only recently been used for the first time, and with the protocol illustrated here, the flexibility in allowing alternative VOCs and photocatalysts to be tested using comparable protocols offers a unique system to elucidate photocatalytic air purification reactions at low concentrations.

A protocol for determining the effectiveness of photocatalysts in degrading indoor air concentration (ppb) model volatile organic carbons such as 2-propanol is described.

We demonstrate a versatile protocol to be used for determining the effectiveness of photocatalysts in degrading indoor air concentration (ppb) volatile ...

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments.

An extrusion method using a calibrated threaded-rod is presented, which allows for mm scale subsampling of aquatic sediment cores. Millimeter-scale sampling is necessary to fully characterize recent event stratigraphy in sediment records.

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, ...

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis. The cyclic polymer exhibits multiple-mode diffusion which is distinct from its linear counterpart. The results demonstrate that the diffusional heterogeneity of polymers that is often hidden behind ensemble averaging can be revealed by the efficient synthesis of the cyclic polymers using the ESA-CF process and the quantitative analysis of the diffusive motion at the single molecule level using the MSD and CDF analyses.

A protocol for the synthesis and characterization of diffusive motion of cyclic polymers at the single molecule level is presented.

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single ...

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution.
Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan&#39;s antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications.
The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

Free solution capillary electrophoresis is a fast, cheap and robust analytical method that enables the quantitative monitoring of chemical reactions in real time. Its utility for rapid, convenient and precise analysis is demonstrated here through analysis of covalent peptide grafting onto chitosan films for improved cell adhesion.

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...