Interpreting Methamphetamine Levels in a High-Use Community

Illicit drug use is a largely hidden phenomenon and population measures are notoriously problematic. Reliable and valid data for local, regional and national public health and other interventions are needed. To address this information we examined temporal trends within and across weeks in methamphetamine (MA) in a single location in order to inform a sampling plan for understanding long-term trends in MA use based on sampling raw influent to waste water treatment plants. The measured concentrations in wastewater are used to estimate the total mass of MA consumed MA rather than the number of doses due to the uncertainty surrounding methamphetamine purity, mass of MA per dose, and the number of doses used per day. Results from a region with high levels of MA use indicate that MA levels do not differ significantly between weekdays and weekends (p=0.1), consistent with a predominately regular, daily use pattern use. The potential contribution of legal sales of d- and l-MA to the mass of MA consumed within the community was estimated to range from 3-8%. Limitations and uncertainties associated with estimating the mass of MA consumption include small contributions of prescription and over-the-counter drugs that are metabolized to MA as well as measurement and sampling variability.Keywords: Temporal patterns, Epidemiology wastewater, Methamphetamine (MA)Keywords: Temporal patterns, Epidemiology wastewater, Methamphetamine (MA

Trace analysis of environmental matrices by large-volume injection and liquid chromatography-mass spectrometry

The time-honored convention of concentrating aqueous samples by solid-phase extraction (SPE) is being challenged by the increasingly widespread use of large-volume injection (LVI) liquid chromatography–mass spectrometry (LC–MS) for the determination of traces of polar organic contaminants in environmental samples. Although different LVI approaches have been proposed over the last 40 years, the simplest and most popular way of performing LVI is known as single-column LVI (SC-LVI), in which a large-volume of an aqueous sample is directly injected into an analytical column. For the purposes of this critical review, LVI is defined as an injected sample volume that is ≥10% of the void volume of the analytical column. Compared with other techniques, SC-LVI is easier to set up, because it requires only small hardware modifications to existing autosamplers and, thus, it will be the main focus of this review. Although not new, SC-LVI is gaining acceptance and the approach is emerging as a technique that will render SPE nearly obsolete for many environmental applications.In this review, we discuss: the history and development of various forms of LVI; the critical factors that must be considered when creating and optimizing SC-LVI methods; and typical applications that demonstrate the range of environmental matrices to which LVI is applicable, for example drinking water, groundwater, and surface water including seawater and wastewater. Furthermore, we indicate direction and areas that must be addressed to fully delineate the limits of SC-LVI

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