Determination of nonylphenol and nonylphenol ethoxylates in wastewater using MEKC

Abstract

Nonylphenol ethoxylates (NPEO(x)) are surfactants which are used worldwide and can be transformed in the environment by microorganisms to form nonylphenol (NP). Analysis of these compounds was carried out with micellar electrokinetic capillary chromatography (MEKC). Different parameters such as background electrolyte (BGE) solution, pH, type of surfactant, and sample stacking were optimized. The use of CHES (20 mM, pH 9.1) in combination with 50 mM sodium cholate as a surfactant as BGE solution, together with sample stacking using 50 mM NaCl in the sample and an injection time of 20 s, provided the best separation of the compounds studied. The method was applied to the determination of target analytes in two types of sludge water coming from two steps of a wastewater treatment plant. Liquid-liquid extraction was carried out using toluene as solvent, resulting in recoveries around 100% for all studied analytes. The presence of NPEO(x) was observed in the first step of the sludge water treatment, based on migration time and UV spectra. Identification was confirmed using tandem MS. LOQs of the studied compounds were in the range of 12.7 to 30.8 ng/mL, which is satisfactory for the analysis of real wastewater samples.

New developments in the trace analysis of organic water pollutants

“…Micellar electrokinetic capillary chromatography-UV detection in combination with MS/MS substance identification was applied to determine NP and NP ethoxylates in wastewater after sample extraction with toluene. LOQs (limit of quantification) were in the range of 12.7 to 30.8 μg L -1 (Núnez et al 2009). …”

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

“…Water-soluble APEOs are often concentrated by solid phase extraction (SPE), using an appropriate hydrophobic stationary phase, followed by elution with a suitable organic solvent [16,17]. Adsorption to granular activated carbon (GAC) followed by Soxhlet extraction [18,19], liquidliquid extraction [20,21] or solid phase microextraction [22] are other techniques that can be used for this purpose.…”

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

“…However, the biodegradation of APEOs is a known source of 4‐NP and 4‐ t ‐OP in the environment. Furthermore, during manufacturing, a nonnegligible amount of APs is discharged into the environment 4–7 . Directive 2000/60/EC of the European Union (EU) listed 4‐ t ‐OP and 4‐NP as part of hazardous substances in 2000 8 .…”

“…Since then, only a limited number of countries are known to permit the use of APEOs. Regardless of these actions, 4‐NP and 4‐ t ‐OP are still found in the environment, especially in industrial wastewater, rivers, and sediments 6 . Similarly, BPA is also an EDC that is extensively used during the production of many epoxy resin linings for food and beverage containers, thermal papers, and polycarbonate plastics 9 .…”

“…manufacturing, a nonnegligible amount of APs is discharged into the environment. [4][5][6][7] Directive 2000/60/EC of the European Union (EU) listed 4-t-OP and 4-NP as part of hazardous substances in 2000. 8 Then, a reduction strategy was applied for 4-NP in the EU in 2003.…”