Surface Water Testing

Bai, Jinyang, et al. "Extraction, determination, dietary and environmental risks assessment of phthalate acid esters in bottled water, liquor, and surface water." Journal of Agriculture and Food Research (2025): 101648.

A highly efficient method, salting-out assisted liquid-liquid extraction (SALLE) combined with gas chromatography tandem mass spectrometry (GC-MS/MS), was developed to determine phthalic acid esters (PAEs) in surface water, bottled water, and liquor samples. The method's key parameters, including sample pH and salting-out solution volume, were optimized using orthogonal design, leading to excellent linearity (R² > 0.995) within the concentration range of 1–200 ng/mL. The limits of detection (LODs) were found to be between 0.01 and 2.00 ng/mL, demonstrating the method's sensitivity and accuracy.

In surface water samples, seven PAEs were identified, including DMP, DEP, DIBP, DBP, DEEP, DCHP, and DEHP. The detection frequencies for these compounds varied, with DMP found in 93% of the samples, DBP in 74%, and others in lower frequencies. Environmental risk assessment using safety factors (SF) and risk quotient (RQ) models indicated moderate to high environmental risks at various surface water sampling sites.

This SALLE-GC-MS/MS method proved to be a rapid, simple, and environmentally friendly approach for PAE determination in surface water. It also provided a reliable means for assessing the dietary and environmental risks posed by PAEs, offering significant insight into the safety of water and liquor consumption.

Liu, Yanling, et al. Microchemical Journal 204 (2024): 111090.

A novel magnetic solid phase extraction (MSPE) method coupled with high-performance liquid chromatography (HPLC) was developed for the determination of quinolone antibiotics in surface water. The MSPE material, MnFe₂O₄@TiO₂, was synthesized by coating TiO₂ on MnFe₂O₄ using an in-situ formation method, and its structure was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM).

Optimal conditions for MSPE were achieved with 15 mg of MnFe₂O₄@TiO₂, a 15-minute extraction time, and 5 mL of a methanol-ammonia solution for elution. The method demonstrated excellent enrichment of quinolone antibiotics, with enrichment factors ranging from 55.8 to 72.1 for fleroxacin, ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin. The linear range for antibiotic determination was 0.004-1 mg/L, with limits of detection (LODs) between 0.0006 and 0.0020 mg/L, and relative standard deviations (RSDs) ranging from 2.1% to 4.9%.

This MSPE-HPLC method was applied to rice paddy water and fish pond water samples, showing recoveries from 78.9% to 105.8% with RSDs of 3.6%–8.7%. The developed method offers a highly sensitive and efficient approach for monitoring quinolone antibiotics in environmental water, facilitating better assessment of water quality and contamination levels.

Nascimento, Madson Moreira, et al. Journal of Chromatography A 1710 (2023): 464230.

A novel liquid-phase microextraction (LPME) technique was developed to detect and preconcentrate nine illicit drugs in surface water and wastewater samples, followed by analysis using gas chromatography-mass spectrometry (GC-MS). The method employed a semi-automated custom microextraction device, coupled with a peristaltic pump for collecting the upper layer of the organic phase. The optimized conditions for LPME included a 100 µL toluene/DCM/EtAc solvent mixture, 30 minutes of extraction under vortex agitation, and a solution pH of 11.6.

The limits of detection for the drugs ranged from 10.5 ng/L (ethylone) to 22.0 ng/L (methylone), with enrichment factors ranging from 39.7 (MDMA) to 117 (cocaethylene). The recovery rates were between 80.4% and 120%. The method was successfully applied to real surface water and wastewater samples collected in Salvador City, Brazil, with cocaine being the most prevalent drug detected in wastewater, concentrations ranging from 312 ng/L to 1,847 ng/L.

The proposed method was evaluated using AGREE metrics, achieving an environmentally friendly score of 0.56. This highlights its potential as a simple, cost-effective, and eco-friendly approach for the detection of illicit drugs in environmental water samples, offering significant advantages in trace-level contamination monitoring and public health risk assessments.