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.

Evaluation of HA negatively charged membranes in the recovery of human adenoviruses and hepatitis A virus in different water matrices

Human adenoviruses (HAdV) and hepatitis A virus (HAV) are shed in the faeces and consequently may be present in environmental waters, resulting in an increase in pathogen concentration that can affect water quality and human health. The aim of this study was to evaluate an adsorption-elution method which utilizes negatively charged membrane HA to determine the efficient recovery of HAdV and HAV from different water matrices and to combine this procedure with a qualitative molecular method (nested RT-PCR and nested PCR). The best efficiency recovery was achieved in distilled water and treated wastewater effluent (100 percent) for both viruses and in recreational lagoon water for HAV (100 percent). The efficiency recovery was 10 percent for HAdV and HAV in seawater and 10 percent for HAdV in lagoon water. The viral detection limit by nested PCR for HAV in water samples ranged between 20-0.2 FFU/mL and 250 and 25 TCID50/mL for HAdV. In conclusion, these results suggest that the HA negatively charged membranes vary their efficiency for recovery of viral concentration depending upon the types of both enteric viruses and water matrices.