Performance of a Novel High Throughput Method for the Determination of VX in Drinking Water Samples
ABSTRACT VX (O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothioate) is a highly toxic organophosphorus nerve agent, and even low levels of contamination in water can be harmful. Measurement of low concentrations of VX in aqueous matrixes is possible using an immunomagnetic scavenging technique and detection using liquid chromatography/tandem-mass spectrometry. Performance of the method was characterized in high-performance liquid chromatography (HPLC)-grade water preserved with sodium omadine, an antimicrobial agent, and sodium thiosulfate, a dechlorinating agent, over eight analytical batches with quality control samples analyzed over 10 days. The minimum reportable level was 25 ng/L with a linear dynamic range up to 4.0 μg/L. The mean accuracies for two quality control samples containing VX at concentrations of 0.250 and 2.00 μg/L were 102 ± 3% and 103 ± 6%, respectively. The stability of VX was determined in five tap water samples representing a range of water quality parameters and disinfection practices over a 91 day period. In preserved tap water samples, VX recovery was between 81 and 92% of the fortified amount, 2.0 μg/L, when analyzed immediately after preparation. Recovery of VX decreased to between 31 and 45% of the fortified amount after 91 days, indicating hydrolysis of VX. However, the preservatives minimized the hydrolysis rate to close to the theoretical limit. The ability to detect low concentrations of VX in preserved tap water 91 days after spiking suggests applicability of this method for determining water contamination with VX and utility during environmental remediation.
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ABSTRACT: Ricinine and abrine are potential indicators of drinking water contamination by ricin and abrin, respectively. Simultaneous detection of ricinine and abrine, along with a-amanitin, another potential biotoxin water contaminant, is reportable through the use of automated sample preparation via solid phase extraction and detection using liquid chromatography/tandem-mass spectrometry. Performance of the method was characterized over eight analytical batches with quality control samples analyzed over 10 days. For solutions of analytes prepared with appropriate preservatives, the minimum reporting level (MRL) was 0.50 mg/L for ricinine and abrine and 2.0 mg/L for a-amanitin. Among the analytes, the accuracy of the analysis ranged between 93 and 100% at concentrations of 1–2.5x the MRL, with analytical precision ranging from 4 to 8%. Five drinking waters representing a range of water quality parameters and disinfection practices were fortified with the analytes and analyzed over a 28 day period to determine their storage stability in these waters. The analytical signal from ricinine was observed to be stable for 28 days after being spiked into all tap waters investigated. The analytical signal for abrine and a-amanitin decreased within 5 h after these analytes were spiked into some drinking waters, but afterwards, remained stable for 28 days. The magnitude of the decrease correlated with common water quality parameters potentially related to sorption of contaminants onto dissolved and colloidal components within the particular water. Even with the decrease, the detectability offered by the method may be 100–1000 times greater than potential toxicological benchmarks, suggesting the utility of the method for all three analytes, with additional quality control precautions for abrine and a-amanitin.Analytical methods 09/2013; 5:5804-5811. DOI:10.1039/c3ay40304a · 1.94 Impact Factor
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ABSTRACT: Catastrophic incidents can generate a large number of samples of analytically diverse types, including forensic, clinical, environmental, food, and others. Environmental samples include water, wastewater, soil, air, urban building and infrastructure materials, and surface residue. Such samples may arise not only from contamination from the incident but also from the multitude of activities surrounding the response to the incident, including decontamination. This document summarizes a range of activities to help build laboratory capability in preparation for sample analysis following a catastrophic incident, including selection and development of fit-for-purpose analytical methods for chemical, biological, and radiological contaminants. Fit-for-purpose methods are those which have been selected to meet project specific data quality objectives. For example, methods could be fit for screening contamination in the early phases of investigation of contamination incidents because they are rapid and easily implemented, but those same methods may not be fit for the purpose of remediating the environment to acceptable levels when a more sensitive method is required. While the exact data quality objectives defining fitness-for-purpose can vary with each incident, a governing principle of the method selection and development process for environmental remediation and recovery is based on achieving high throughput while maintaining high quality analytical results. This paper illustrates the result of applying this principle, in the form of a compendium of analytical methods for contaminants of interest. The compendium is based on experience with actual incidents, where appropriate and available. This paper also discusses efforts aimed at adaptation of existing methods to increase fitness-for-purpose and development of innovative methods when necessary. The contaminants of interest are primarily those potentially released through catastrophes resulting from malicious activity. However, the same techniques discussed could also have application to catastrophes resulting from other incidents, such as natural disasters or industrial accidents. Further, the high sample throughput enabled by the techniques discussed could be employed for conventional environmental studies and compliance monitoring, potentially decreasing costs and/or increasing the quantity of data available to decision-makers.Environment international 02/2014; DOI:10.1016/j.envint.2014.01.021 · 5.66 Impact Factor
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ABSTRACT: An array of fluorogenic probes is able to discriminate between nerve agents, sarin, soman, tabun, VX and their mimics, in water or organic solvent, by qualitative fluo-rescence patterns and quantitative multivariate analysis, thus making the system suitable for the in-the-field detection of traces of chemical warfare agents as well as to differentiate between the real nerve agents and other related compounds.Journal of the American Chemical Society 03/2014; 136(11). DOI:10.1021/ja500710m · 11.44 Impact Factor