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.

Modifications to a commercially available linear mass spectrometer for mass‐resolved microscopy with the pixel imaging mass spectrometry (PImMS) camera

“…Mass spectrometry (MS) is used in a number of applications, from the analysis of agricultural products and medical samples, to security screening. [1][2][3] Different applications have different requirements in terms of acquisition speed, range, accuracy, and resolution such that it would be impossible to create the 'perfect' mass spectrometer which excels in all categories. However, by choosing realistic goals for a few parameters it is possible to concentrate on improving those characteristics which matter, in a systematic fashion.…”

Stability of ricinine, abrine, and alpha-amanitin in finished tap water

“…Some analytes of interest for water security are inherently unstable. 54 However, in the event of drinking water contamination, there will be interest in what the analytic possibilities are for these contaminants, regardless of any stability challenges. The primary purpose of this paper is to investigate the practical aspects of laboratory analysis, including choice of preservation strategy, for ricinine, abrine, and a-amanitin in the drinking water utilizing solid phase extraction followed by HPLC-tandem mass spectrometry.…”

Sensitive Untargeted Screening of Nerve Agents and Their Degradation Products Using Liquid Chromatography–High Resolution Mass Spectrometry

“…As DPs are more stable than their parent compounds, they have been used as markers to indicate the presence of the original nerve agents. However, most recent efforts have mainly focused on several classical NAs and relevant alkyl alkylphosphonic acids (AAPAs). − According to verification analysis of the Chemical Weapons Convention (CWC) and literature reports, ,− the degradation pathway of Schedule 1.A.01–1.A.03 in CWC is shown in Figure ; all these NAs and their DPs are of concern to CWC forensic verification. Moreover, in their hydrolysis/oxidation products, O -alkyl N , N -dialkyl phosphoramidic acids (g), 2-( N , N -dialkylamino)­ethanesulfonic acids (m), etc., may be generally assumed to be relevant to the CWC nonscheduled reportable chemicals (NSRC).…”