Drinking Water Testing

Alimzhanova, M., Mamedova, M., Ashimuly, K., Alipuly, A., & Adilbekov, Y. (2022). Food Chemistry: X, 14, 100345.

A rapid and efficient method using miniaturized solid-phase microextraction (mini-SPME) followed by gas chromatography–mass spectrometry (GC-MS) was developed for the identification of eight endocrine disruptors (atrazine, diethylstilbestrol, hexestrol, estrone, estradiol, ethinylestradiol, norgestrel, and megestrel) in drinking water samples.

The extraction conditions were optimized, with the best results obtained at an extraction temperature of 80 °C, and extraction and preincubation times of 60 and 20 minutes, respectively. The linear range for the detection of endocrine disruptors was from 10.0 to 1000 μg/mL, with detection limits between 0.020 and 0.087 μg/mL. The method showed excellent linearity, with correlation coefficients (r²) between 0.96 and 0.99.

This approach offers a novel method for detecting endocrine disruptors at very low concentrations and demonstrates the potential to combine multiple detection techniques for precise qualitative and quantitative analysis of these compounds in aqueous samples.

Khairy, G. M., Amin, A. S., Moalla, S. M., Medhat, A., & Hassan, N. (2022). RSC advances, 12(42), 27679-27686.

A new fluorescence chemosensor, (Z)-2-(1-(3-oxo-3H-benzo[f]chromen-2-yl)ethylidene)hydrazine-1-carbothioamide (CEHC), has been developed for the determination of Fe(iii) in drinking water.

The optimal conditions for the sensor were achieved using an acetate buffer solution at pH 5.0. In this method, Fe(iii) is determined by the static quenching of the probe's luminescence as the concentration of Fe(iii) increases. The CEHC sensor binds to Fe(iii) in a 1:1 ratio, with a binding constant Ka of 1.30 × 10⁴ M^-1. The sensor exhibits greater sensitivity, selectivity, and faster fluorescence quenching for Fe(iii) compared to other heavy metal ions. Selectivity was confirmed against seven other metal ions (Mn(ii), Al(iii), Cu(ii), Ni(ii), Zn(ii), Pb(ii), and Cd(ii)).

A calibration curve was established using the Stern–Volmer equation, with a linear range of 2.50–150 μM and a correlation coefficient of 0.9994. The limit of detection (LOD) was 0.76 μM. The method was successfully applied to determine Fe(iii) in drinking water samples, and the accuracy of the chemosensor was confirmed by atomic absorption spectrometry.

Xu, G., Yang, C., Zhang, H., & Li, B. (2024). Journal of Chromatography A, 465541.

Routine monitoring of per- and polyfluoroalkyl substances (PFASs) in drinking water is critical for public health.

In this study, a fluorinated covalent organic framework (COF) was synthesized at room temperature using tetra-(4-aminophenyl) methane (TAM) and 2,3,5,6-tetrafluoro-terephthalal (TFTA) as building blocks, resulting in TAM-TFTA-COF. The adsorption properties of PFASs on TAM-TFTA-COF were examined through adsorption model fitting and molecular calculations. The TAM-TFTA-COF was used as the solid-phase extraction (SPE) cartridge packing to enrich PFASs. When combined with liquid chromatography–tandem mass spectrometry, the method demonstrated good linearity within the range of 1.25–375 ng·L^-1, low limits of detection (0.03–0.24 ng·L^-1), and excellent precision, with intraday and interday relative standard deviations (RSD) under 10.3%. This analytical method can be applied to the determination of PFASs in tap water, spring water, and lake water with satisfactory accuracy.