Wastewater Testing

Zhou, Jing, et al. "Determination of four cannabinoids in wastewater based on a hyperbranched mixed-mode anion exchange magnetic solid-phase extraction adsorbent combined with UHPLC-MS/MS."

Cannabis, the most frequently abused drug worldwide, presents significant challenges for monitoring due to the low concentrations of cannabinoids in wastewater caused by their high lipophilicity. A novel hyperbranched mixed-mode anion exchange magnetic adsorbent, Fe₃O₄@poly(GMA/DVB-WAX), was developed for the selective extraction of four key cannabinoids: Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN), and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH) from wastewater. This adsorbent, created through copolymerization of glycidyl methacrylate (GMA) and divinylbenzene (DVB) on Fe3O4 microspheres and further modified with ethylenediamine (EDA) and 1,4-butanediol glycidyl ether (BDDGE), exploits hydrophobic interactions, electrostatic forces, π-π stacking, and hydrogen bonding to effectively extract the cannabinoids.

The magnetic solid-phase extraction (MSPE) process is rapid, taking only five minutes, with recovery rates ranging from 69.4% to 94.0%. The MSPE-UHPLC-MS/MS method, optimized and validated, shows excellent linearity (r² > 0.9962) within the 0.5–100 ng/L range, with detection limits between 0.17-0.33 ng/L and quantification limits from 0.50–1.00 ng/L. This method provides a convenient, sensitive, and reliable approach for cannabinoid detection in wastewater, demonstrating its potential for monitoring trace amounts of these compounds and enhancing public health risk assessments.

Cai, Qihong, et al. Microchemical Journal 207 (2024): 111849.

Quinolone antibiotics, commonly used in human and veterinary medicine, pose significant environmental risks due to their persistence in wastewater. These compounds, including pefloxacin (PFX) and fleroxacin (FLX), are often discharged into wastewater systems through human and animal excretion, leading to contamination of water bodies and potential ecological and health hazards. This study introduces a novel first derivative synchronous fluorescence spectrometry (SFS) method for the accurate and sensitive determination of PFX and FLX in wastewater samples.

The method enhances the fluorescence intensity of PFX and FLX by complexing them with Al³⁺, utilizing a wavelength difference (Δλ = 155 nm) to separate the overlapping fluorescence spectra. By applying first derivative processing to the narrowed synchronous fluorescence spectra, the method successfully eliminates interference from both the compounds and the wastewater matrix. The limits of detection for PFX and FLX were 0.0086 ng/mL and 0.0068 ng/mL, with linear ranges of 0.1–40 ng/mL and 0.2–80 ng/mL, respectively. Recovery rates in wastewater samples ranged from 88.6% to 98.6%.

Compared to conventional HPLC methods, this new technique offers simplified sample pretreatment, faster detection, and excellent accuracy. The first derivative SFS method is a promising approach for routine monitoring of quinolone antibiotic residues in wastewater, providing an efficient solution to address environmental contamination and public health risks.

Roustaei, Farideh, et al. "Spectrophotometric determination of phenol impurity in phenoxyethanol and phenol index of drinking water and municipal wastewater effluent after salting-out assisted liquid phase microextraction (SA-LPME)." Heliyon 10.5 (2024).

A novel analytical method based on salting-out-assisted liquid phase microextraction (SA-LPME) has been developed for the sensitive determination of phenol in drinking water, treated wastewater, and the impurity phenol in 2-phenoxyethanol (PE). This method utilizes a spectrophotometric technique, where a solution of PE is treated with 4-aminoantipyrine (4-AAP) and hexacyanoferrate, followed by the addition of NaCl to induce the formation of a two-phase system. Fine droplets of PE act as the extractant phase, which are then separated and centrifuged to extract the red derivative, measured at 520 nm.

Optimized by Response Surface Methodology (RSM) with Box-Behnken Design (BBD), the conditions were fine-tuned to achieve a limit of detection of 0.7 ng/mL for water and 0.22 μg/g for PE. The method demonstrated high precision with relative standard deviations (RSD) ranging from 2.4% to 6.8% and excellent linearity (r² = 0.9983–0.9994). The enrichment factor achieved was 65 for a 10 mL sample.

The method was successfully applied to determine phenol in pharmaceutical PE samples, drinking water, and treated wastewater, with recoveries ranging from 97.5% to 107.8%. This demonstrates the potential of SA-LPME for environmental monitoring with minimal matrix interference, offering a cost-effective and efficient alternative for water quality analysis.