A green method for the determination of illicit drugs in wastewater and surface waters-based on a semi-automated liquid-liquid microextraction device.

Liquid-phase microextraction (LPME) is a simple, low-cost, and eco-friendly technique that enables the detection of trace concentrations of organic contaminants in water samples. In this work, a novel customized microextraction device was developed for the LPME extraction and preconcentration of nine illicit drugs in surface water and influent and effluent wastewater samples, followed by analysis by GC-MS without derivatization. The customized device was semi-automated by coupling it with a peristaltic pump to perform the collection of the upper layer of the organic phase. The extraction parameters affecting the LPME efficiency were optimized. The optimized conditions were: 100 µL of a toluene/DCM/EtAc mixture as extractor solvent; 30min of extraction time under vortex agitation (500rpm) and a solution pH of 11.6. The limits of detection and quantification ranged from 10.5ng L-1 (ethylone) to 22.0ng L-1 (methylone), and from 34.9ng L-1 to 73.3ng L-1 for these same compounds, respectively. The enrichment factors ranged from 39.7 (MDMA) to 117 (cocaethylene) and the relative recoveries ranged from 80.4% (N-ethylpentylone) to 120% (cocaine and cocaine-d3). The method was applied to real surface water, effluent, and influent wastewater samples collected in Salvador City, Bahia, Brazil. Cocaine was the main drug detected and quantified in wastewater samples, and its concentration ranged from 312ng L-1 to 1,847ng L-1. Finally, the AGREE metrics were applied to verify the greenness of the proposed method, and an overall score of 0.56 was achieved, which was considered environmentally friendly.

Exploratory analysis of the presence of 14 carbonyl compounds in bottled mineral water in polyethylene terephthalate (PET) containers.

Carbonyl compounds (CCs) can migrate from bottles to mineral water because of plastic degradation. An exploratory analysis of the presence a significant number of CCs (14) in bottled mineral water with and without gas in polyethylene terephthalate (PET) containers was performed using ultra-fast liquid chromatography coupled to mass spectrometry (UFLC-MS). The data from the analysis was submitted to chemometric treatment (principal component analysis, PCA). Formaldehyde, acetaldehyde, and benzaldehyde were found in all samples (0.07-125 ng mL-1). Acrolein and acetone were present in 81% and 75% of the samples, respectively. The concentration of acrolein in carbonated water was up to 3.8 times greater than that measured in non-carbonated water (0.07-0.44 ± 0.01 ng mL-1). PCA analysis showed that gasification can influence the composition of CCs present in mineral water and that the plastic material of the bottles is a likely source of CCs. In addition, benzaldehyde levels may be associated with the use of recycled materials.

Determination of free- and bound-carbonyl compounds in airborne particles by ultra-fast liquid chromatography coupled to mass spectrometry.

This study presents the development and application of a new analytical methodology for determination of free- and bound-carbonyl compounds (CC) (as the CC themselves and as the hydroxyalkylsulfonic acids - HASA, respectively) in airborne particles. Free- and bound-CC determination were done through reaction with 2,4-dinitrophenylhydrazine (2,4-DNPH) and analysis by UFLC-MS. The method was successfully validated, showing good figures for linearity (R2 ≥ 0.9937), sensibility (3 fg ˂ LOD ˂ 20 fg for methacrolein and heptanal, respectively) and repeatability (5.9% ˂ RSD ˂ 13%). The proposed method was successfully applied in real samples of inhalable atmospheric particulate matter (PM10) and urban dust certified reference material (SRM 1649 b). The main CC determined in the SRM 1649 b was formaldehyde (75.4 µg g-1 in the free form, and 1898 µg g-1 in the bound form). In addition, for the bound-CC form (HASA), concentrations were determined for acetaldehyde (60.3 µg g-1), acetone (20.5 µg g-1), acrolein (9.15 µg g-1), propionaldehyde (17.1 µg g-1) and valeraldehyde (12.2 µg g-1). For PM10 samples, formaldehyde (148 µg g-1) and acetaldehyde (28.9 µg g-1) were quantified as free aldehydes and as HASA (hydroxymethanelsulfonic acid and hydroxyethanesulfonic acid were 432 µg g-1 and 211 µg g-1, respectively). Other bound-CC were, on average, within 19.2 µg g-1 (acrolein) and 62.1 µg g-1 (valeraldehyde). For all samples, acetone, acrolein, propionaldehyde and valeraldehyde were quantified only as HASA (bound-CC). Therefore, we could identify and quantify six carbonyl compounds using the proposed method. It is worth mentioning the hydrolysis step was crucial for the correct quantification of the HASAs. This was, in turn, what enabled the quantification of a greater number of analytes in the airborne samples. Hence, this procedure was found to be comprehensive, precise, accurate and suitable to be employed for determination of free-CC and HASA (bound-CC) in atmospheric particulate samples.