Abstract
The investigation of clandestine laboratories poses serious hazards for first responders, emergency services, investigators and the surrounding public due to the risk of exposure to volatile organic compounds (VOCs) used in the manufacture of illicit substances. A novel gas sampling interface using open microfluidic channels that enables the extraction of VOCs out of the gas phase and into a liquid, where it can be analysed by conventional detection systems, has recently been developed. This paper investigates the efficiency and effectiveness of such a gas-to-liquid (GTL) extraction system for the extraction of amphetamine-type substances (ATS) and their precursors from the vapour phase. The GTL interface was evaluated across a range of different ATS and their precursors (methamphetamine, dimethylamphetamine, N-formylmethamphetamine, benzaldehyde, phenyl-2-propanone, ephedrine and pseudoephedrine) at concentrations ranging between 10 and 32 mg m−3. These gas samples were produced by a gas generation system directly in Tedlar® bags and gas canisters for controlled volume sampling. When using gas sampled from Tedlar® bags, four of the seven compounds were able to be extracted by the GTL interface, with the majority of the VOCs having extraction yields between 0.005% and 4.5%, in line with the results from an initial study. When samples were taken from gas canisters, only benzaldehyde was able to be detected, with extraction efficiencies between 0.2% and 0.4%. A custom-built mount for the GTL interface helped to automate the extraction process, with the aim of increasing extraction efficiency or reducing variability. However, the extraction efficiency did not improve when using this accessory, but the procedure did become more efficient. The results from the study indicated that the GTL interface could be employed for the collection of gaseous ATS and incorporated into mobile detection systems for onsite collection and analysis of volatile compounds related to ATS manufacture.
Highlights
Over the 2015–2016 financial year, Australian law enforcement agencies identified 575 clandestine amphetamine-type substances (ATS) laboratories [1]
Of the seven compounds tested in this research, four were able to be detected when prepared as vapour samples in a Tedlar® bag and immediately extracted through the GTL interface (Table 1)
The GTL interface was able to extract benzaldehyde, P2P, MA, DMA and FMA out of the prepared gas samples with a calculated 1%–10% extraction efficiency range, on average, based on an assumed starting concentration. These extractions were able to be conducted for 6 min using a 300 mL gas sample, showing that the microfluidic GTL interface has potential for use as a screening tool for the extraction of ATS and their precursors
Summary
Over the 2015–2016 financial year, Australian law enforcement agencies identified 575 clandestine amphetamine-type substances (ATS) laboratories [1]. ATS manufacture (including 3,4-methylenedioxymethylamphetamine (MDMA)) and pseudoephedrine extraction facilities accounted for 63.6% of all clandestine laboratory detections [1]. In conjunction with a myriad of potential hazards associated with investigating clandestine laboratories, their common occurrence in residential areas poses a health risk to the general public, who may come into contact with toxic compounds and chemical waste associated with ATS synthesis [2,3]. The occurrence of different synthetic methods raises significant health concerns for investigators, and first responders as potential hazards may be unknown, with possible exposure to toxic volatile organic compounds (VOCs) [4]. In the synthesis of methamphetamine (MA) from ephedrine/pseudoephedrine via complex iodine/phosphorus methods, for example, iodine, acids, phosphine and various toxic by-products have been identified [5,6]. Vapour concentrations for MA, iodine and hydrochloric acid have been detected at ranges between 0.01 and 5 mg m−3 [7]
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