Establishment of rapid, sensitive, and quantitative liquid chromatography-electrospray ionization-tandem mass spectrometry method coupled with liquid-liquid extraction for measurement of urinary bisphenol A, 4-t-octylphenol, and 4-nonylphenol

RATIONALE

Bisphenol A (BPA), 4-t-octylphenol (4-t-OP), and 4-nonylphenol (4-NP) are ubiquitous manufactured chemicals classified as endocrine disruptors. Now these substances are prevalent and found in a wide range of biological and environmental matrices globally. Acting as xenoestrogens, their target is to bind estrogen receptors and compete against natural hormones. Thus, there is an increasing concern on their negative health consequences.

METHODS

A rapid, sensitive, and robust method was established, validated, and used for the trace analysis of BPA, 4-t-OP, and 4-NP in human urine using liquid chromatography-electrospray ionization-tandem mass spectrometry.

RESULTS

The linear ranges for BPA, 4-t-OP, and 4-NP were 5.0-500 ng/mL. The correlation coefficient was higher than 0.996. The limit of detection and limit of quantitation for the compounds were 0.001, 0.007, and 0.005 ng/mL and 0.005, 0.023, and 0.180 ng/mL, respectively. The recoveries were as follows: 99.539%-108.557%, 97.780%-110.768%, and 99.694%-106.908% for BPA, 4-NP, and 4-t-OP respectively, with relative standard deviation <8.26%.

CONCLUSIONS

The established method was also applied effectively for the determination of BPA, 4-t-OP, and 4-NP levels in 15 human urine samples. This method was specifically developed for easy and precise analysis of BPA, 4-t-OP, and 4-NP in human urine. The method developed has been shown to be accurate, precise, and sensitive.

Strategies for selecting optimal sampling and work-up procedures for analysing alkylphenol polyethoxylates in effluents from non-activated sludge biofilm reactors

Trace-level analysis of alkylphenol polyethoxylates (APEOs) in wastewater containing sludge requires the prior removal of contaminants and preconcentration. In this study, the effects on optimal work-up procedures of the types of alkylphenols present, their degree of ethoxylation, the biofilm wastewater treatment and the sample matrix were investigated for these purposes. The sampling spot for APEO-containing specimens from an industrial wastewater treatment plant was optimized, including a box that surrounded the tubing outlet carrying the wastewater, to prevent sedimented sludge contaminating the collected samples. Following these changes, the sampling precision (in terms of dry matter content) at a point just under the tubing leading from the biofilm reactors was 0.7% RSD. The findings were applied to develop a work-up procedure for use prior to a high-performance liquid chromatography-fluorescence detection analysis method capable of quantifying nonylphenol polyethoxylates (NPEOs) and poorly investigated dinonylphenol polyethoxylates (DNPEOs) at low microg L(-1) concentrations in effluents from non-activated sludge biofilm reactors. The selected multi-step work-up procedure includes lyophilization and pressurized fluid extraction (PFE) followed by strong ion exchange solid phase extraction (SPE). The yields of the combined procedure, according to tests with NP10EO-spiked effluent from a wastewater treatment plant, were in the 62-78% range.

MEKC as a powerful growing analytical technique

This review summarizes the principle and the developments in MEKC in terms of separation power, sensitivity, and detection approaches more than 25 years after its appearance. Newly used surfactants are mentioned. Classical and new sample concentration techniques in MEKC are described. The different detection approaches in MEKC with advantages, limitations, and future prospects are also discussed. This review highlights the wider application of MEKC in different analytical fields. Various recent selected applications of this technique in different analytical fields are reported.