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[Display omitted] • POCIS sampling was applied to 3-PBA in wastewater in a WWTP. • The WWTP was continuously monitored for 392 days. • Concentrations of 3-PBA were in the range of 24.3 to 335.2 ng/L. • This is the first report of POCIS sampling for 3-PBA in wastewater. Wastewater-based epidemiology (WBE) is a methodological approach that aims to obtain epidemiological information through wastewater analysis, by identifying endogenous metabolism products. Pyrethroid insecticides are commonly used but just a few studies evaluated concentrations of pyrethroid metabolites in wastewater. A cost-effective and efficient sampling strategy for WBE studies is the use of polar organic chemical integrative samplers (POCIS). This study aimed to develop and evaluate a method for estimating the concentration of the pyrethroid insecticide 3-phenoxybenzoic acid (3-PBA) using POCIS sampling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The sampler sorbent was extracted with methanol, followed by a double solid phase extraction (SPE) clean-up. The extraction procedure had yields in the range of 95.7–100.4 %. There were 27 collection cycles, with POCIS samplers changed every 14 days. The analyte 3-PBA was measured in all collections. The concentration of 3-PBA in the POCIS sorbent was 208.6–2456.9 ng g−1. The sampling rate was 0.096 L/day and the resulting estimated concentration in wastewater was 24.3 to 335.2 ng/L. This is the first study evaluating POCIS sampling to measure a pyrethroid metabolite in water or wastewater samples. [ABSTRACT FROM AUTHOR]

• Gentamicin was measured with high sensitivity in dried blood spots. • Total gentamicin was obtained by adding concentrations of the C1, C1a and C2 forms. • Gentamicin was stable for 21 days at − 20 and 8 °C, but only for 24 h at room temperature. • The assay was applied to the measurement of gentamicin levels in neonate patients. Gentamicin sulfate (GEN) is an aminoglycoside antibiotic with a narrow therapeutic range of plasma concentrations. The collection of venous blood represents a significant burden for patients, especially in neonatology. Dried blood spots (DBS) obtained from capillary blood can be an alternative for drug measurements in this particular population. This study aimed to develop and validate an assay for the quantification of GEN in DBS using UHPLC-MS/MS. Total GEN concentrations were obtained by adding the individual concentrations of the GEN forms C1, C1a, and C2. The assay used a DBS disk containing approximately 17 μL of blood for GEN quantitation in the range of 0.1–40 mg L-1. Measurement accuracy for total GEN was in the range of 102.6–108.6%, inter-assay precision was 11.3–13.1% and intra-assay precision was 9.1–12.8.% GEN was stable for 21 days at − 20 and 8 °C, but only for 24 h at room temperature. Blood Hct affected the accuracy within acceptable limits (93.8–95% at Hct% of 30, 104.3–113% at Hct% of 50). Blood spotted volume did not affect GEN measurement accuracy. Concentrations of GEN in DBS obtained after heel pricks were correlated to plasma levels in a small cohort of neonatal patients. However, percentual differences between estimated plasma concentrations and actual plasma levels presented values between − 64–35.3% (average difference of − 1.9%). The use of DBS for the measurement of GEN concentrations can increase access to TDM of this antibiotic due to the ease of sample collection and the facilitated specimen transportation logistics when testing is not available onsite. [ABSTRACT FROM AUTHOR]

[Display omitted] • POCIS samplers were calibrated for 9 compounds related to drugs abuse consumption. • POCIS sorbent was extracted with methanol and submitted to a dual SPE clean-up. • Target compounds were sensitively measured using UHPLC-MS/MS. • First report of POCIS sampling with Oasis® HLB for cannabis metabolites. • A Brazilian wastewater treatment plant was continuously monitored for 392 days. Passive sampling of wastewater using polar organic chemical integrative samplers (POCIS) is an interesting and cost-effective strategy for the quantification of biomarkers of drugs of abuse consumption in epidemiological studies. Particularly when combined with sensitive analytical method as ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS), POCIS sampling allows the long-term and sensitive determination of a wide range of analytes. In this study, a comprehensive analytical method integrating POCIS sampling, selective solid-phase extraction (SPE) of POCIS extracts, and analysis by UHPLC-MS/MS was developed and successfully validated for 12 biomarkers of substance use, with potential use in wastewater-based epidemiology. Chromatographic separation was achieved in 11 min. The assay has a wide liner range, with lower limits of quantification of 5 ng g−1 of POCIS sorbent. The selective SPE procedure, combining both cation and anion exchange cartridges, resulted in low matrix effects (-19.3 to 22.8% for compounds with a deuterated analog internal standard and 33.4 to 42.5% for anhydroecgonine methyl ester) and high extraction yields (93.4 to 106.4%). The lab-made POCIS sampler with Oasis® HLB sorbent was adequately calibrated for 9 compounds (4 drugs of abuse, 4 drug metabolites, and 1 human non-drug lifestyle markers). The method was applied in a wastewater treatment plant in Brazil, with continuous monitoring for 392 days in 2020–2021. The highest calculated wastewater concentration among drugs of abuse and metabolites was found for benzoylecgonine (431.5 ± 190.6 ng L-1), followed by 11-nor-9-carboxy-Δ9-THC (58.3 ± 21.1 ng L-1). The assay described in this study can be used as an effective tool to monitor the presence of relevant drug consumption biomarkers in wastewater, a relevant epidemiologic strategy currently limited due to the sophisticated infrastructure needed for representative sampling. [ABSTRACT FROM AUTHOR]