Search

Perchlorate is a low molecular weight highly soluble anion. It occurs naturally in the environment, primarily near potash deposits and in arid regions. The determination of perchlorate in human milk is of interest in vulnerable populations such as infants and pregnant women. In this study, a sensitive and selective isotope dilution ion chromatography/tandem mass spectrometry (ID IC-MS/MS) method was developed and validated for the determination of perchlorate in human milk samples collected from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study. The limit of detection (LOD) was 0.27 µg·kg−1 for human milk. A total of 439 human milk samples were analysed with measurable levels of perchlorate in most of the milk samples, and the mean value was 7.62 ± 32.7 µg·kg−1. This project provided important information related to perchlorate levels in human milk collected across Canada and the extent to which pregnant women and their infants may be exposed to perchlorate. A dietary exposure assessment was also conducted in infants based on the measured values in human milk. The mean perchlorate probable daily intakes (PDIs) for infants consuming human milk were 0.31 ± 0.07 μg/kg bw/day for infants under 1 year and 0.17 ± 0.10 μg/kg bw/day for infants between 1 and 3 years old. None of the estimates exceeded the FAO/WHO provisional maximum tolerable daily intake (PMTDI) of 10 μg/kg bw/day. [ABSTRACT FROM AUTHOR]

• Polarity switching for simultaneous mass analysis in positive and negative ESI. • Quantitation of organic UV filters in chlorinated waters. • SPE allows for preconcentration of low level analytes in swimming pools. Ultraviolet filters (UVFs) absorb UV light and are comprised of numerous classes of compounds including inorganic and organic. They have been used for decades in protecting humans from skin damage and cancer. Recent studies have shown that UVFs are found in many phases of abiotic and biotic systems with their physical-chemical characteristics determining environmental fate and potential biological impacts such as bioaccumulation. This study developed a unified method to quantify eight UVFs (avobenzone, dioxybenzone, homosalate, octinoxate, octisalate, octocrylene, oxybenzone, and sulisobenzone) by solid phase extraction and ultra-high performance liquid chromatography-tandem mass spectrometry using polarity switching. The validated method resulted in accuracies ranging from 75 to 112%, MLD/MLQs of 0.00015/ 0.00049 to 0.0020/ 0.0067 ng mL−1, and precisions of 1.8 to 22.6% (intraday) and 1.3 to 17.2% (interday). The method was applied to chlorinated outdoor pool waters in the City of Winnipeg, Manitoba, Canada. This method could be adapted for a variety of chlorinated and unchlorinated waters such as drinking water, wastewater, and surface waters. [ABSTRACT FROM AUTHOR]

The increasing variability of the illicit drug market has imposed serious health risks for people who use drugs (PWUD), particularly due to the increasing co-occurrence of opioids and etizolam (or other benzodiazepines) in some jurisdictions. A miniature mass spectrometer (MS) equipped with paper capillary spray ionization was evaluated for its ability to quantify fentanyl, fluorofentanyl, carfentanil, and etizolam in illicit drug samples. Prior to testing actual drug samples, inter- and intra-day reproducibility, calibration linearity, and analytical sensitivity were assessed. The development of a continuous spray solvent delivery system improved MS/MS quantitation by prolonging ionization stability. A simple, rapid and quantitative tandem mass spectrometry method was developed and employed for the analysis of real-world illicit drug samples provided by PWUD at a harm reduction site in Victoria, British Columbia, Canada. Limits of detection ranged from 0.001 to 0.24% w/w of illicit analyte in the original solid drug samples. Target analytes were detected and quantified via the miniature MS system for samples where conventional on-site drug checking technologies were not always effective. These promising results demonstrate the potential role for miniature mass spectrometer systems for on-site drug checking services that can be both sensitive to trace, toxic levels as well as adaptable/selective for new drug threats as they appear in the illicit drug supply. [Display omitted] • The increased variability of the illicit drug market has imposed serious health risks for people who use drugs (PWUD). • A rapid & quantitative miniature MS method was developed and employed for the analysis of real-world illicit drug samples. • Target analytes were quantified via miniature MS, where other on-site drug checking technologies were not always effective. • Miniature MS systems for on-site drug checking services are sensitive, adaptable and selective for new drug threats. [ABSTRACT FROM AUTHOR]