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Sprayed liquid-gas extraction of semi-volatile organophosphate Malathion from air and contaminated surfaces

Abstract

In this study, a new air sampling method termed sprayed liquid–gas extraction (SLGE) was developed for semi-volatile organic compounds. Water droplets with an average diameter of less than 10 μm were created, using a flow blurring nebulizer from distilled water and the gas-phase sample. This allowed the fast, simple and highly-efficient enrichment of trace levels of the widely used organophosphate insecticide malathion, which is also an accepted simulant for the potent nerve-agent VX. After spraying, extraction and solvent evaporation, the collected malathion molecules were dissolved in 100 μL organic solvent and analyzed using gas chromatography-mass spectrometry. Different parameters including SLGE duration, gas and extracting-agent flow-rate, humidity and memory effect were evaluated and optimized. The method was compared with standard air-sampling tubes containing XAD-2 and XAD-4 polymers and also the liquid-trapping method. Combining simplicity with cost-effectiveness, the SLGE method shows outstanding extraction efficiency compared to the standard methods. Using the optimized method, the limits of detection (LOD) and quantification (LOQ) were determined to be 7.53 and 25.11 ng L−1, respectively. The developed method was compared to a standard extraction with XAD-2 tube which was run in parallel to the SLGE. These methods were used to extract a mixture of malathion, 2,4-dinitrotoluene (explosive marker), 4-chloro-3-methylphenol, carbaryl (insecticide), dimethoate (organophosphate insecticide), atrazine (herbicide) and permethrin (insecticide) in synthetic air. These compounds were also deposited on a steel plate and a composite building material and the air above these materials was sampled.

Sprayed liquid-gas extraction in combination with ion mobility spectrometry: a novel approach for the fast determination of semi-volatile compounds in air and from contaminated surfaces

Abstract
We developed a fast, simple and highly-efficient enrichment procedure for trace levels of semi volatile organic compounds from air and surfaces and combined it with ion mobility spectrometry as field-deployable and rapid analytical technique. Our new technique, the sprayed liquid-gas extraction, was developed and optimized to allow the enrichment of semi volatile organic compounds. The air sample is pumped through a flow blurring nebulizer together with water. The sprayed liquid is collected and the organic compounds are transferred from the water phase to n-hexane via a miniscale liquid-liquid extraction. 50 μL of the n-hexane extract is applied to a fiber tape. After the n-hexane has evaporated, the fiber tape is transferred to the thermodesorber unit of a GDA-X ion mobility spectrometer (Airsense, Schwerin, Germany). The whole sampling and the sample preparation procedure takes no longer than 15 min and only requires 2.5 mL organic solvent. The method was optimized for Malathion, a widely used organophosphate insecticide and an accepted simulant for the nerve-agent, VX. Malathion provides defined ion mobility spectra in both, the positive and negative mode. The positive spectra show one major peak with a reduced mobility of 1.197 cm2 Vs−1 and an additional peak at 1.449 cm2 Vs−1 with lower intensity. A major product ion peak of 1.720 cm2 Vs−1 can be detected in negative mode together with an additional peak of low intensity at 1.403 cm2 Vs−1. The detection limit of the ion mobility spectrometer is approximately 20 ng absolute.

Robotic and autonomous countermeasures

Security and defence discussions are now filled with speculation about robot weapons and artificial intelligence (AI). The problem is, security cannot be built on robotic weapons, autonomous systems or AI alone. Autonomous systems are more like operating platforms and firing systems than weapons per se. For example, electro-optical weapons, firearms, missiles, and nuclear weapons are defined by their impact. Robotised features simply increase that impact.

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1st DGKM-CBRN Forum (Berlin)

5/May/2018

Christoph Amelunxen from the University of Paderborn presented "TOXI-triage - Introduction to an EU-Development Project" at the 1st DGKM-CBRN Forum on 5th May in Berlin, Germany.

The1st DGKM-CBRN Forum focused on medical mission management and medical care in a mass casualty of CBRN-contaminated patients.
The aim of this forum is to provide, via selected scientific contributions and practical demonstrations, with a platform for professional exchange and networking opportunities on the topic of CBRN-related medical protection.

Expert Evaluation Panel (Moreton in Marsh)

17/Apr/2018

With just 18 months to project completion, the Expert Evaluation Panel (EEP) Meeting in April in Moreton in Marsh will critically evaluate plans for the FTX and ensure that we are on track for the final push to successful completion.

The panel of experts will be composed by CBRN End User experts from Police, Fire, Ambulance, Military and Hospitals.
The purpose of their review is to assess and ensure that the planned FTXs will enable suitable evaluation of the project technologies.

7th German IMS users conference (University of Reutlingen)

6-7/Mar/2018

Some members of TOXI-triage attended the “7th German IMS users conference” held at the University of Reutlingen and hosted by Professor J.I. Baumbach. More than 20 presentations were scheduled and about 80 people attended the event.
Helko Borsdorf (UFZ) held a presentation titled “Sprayed liquid-gas extraction in combination with ion mobility spectrometry: A novel approach for the fast determination of semi-volatile compounds in air and from contaminated surfaces”.

VGBF in Salzburg (Salzburg)

20/Feb/2018

Christoph Amelunxen from the University of Paderborn presented "Herausforderungen beim MANV in CBRN-Lagen - Technologien und Workshopergebnisse" ("Mass-Casualty Incident Challenges in CBRN - Technologies and Workshop Results") at the annual conference of the VGBF in Salzburg, Austria.

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