Matrix Effects on Water Analysis for Alkylphenols Using Solid Phase Extraction Gas Chromatography-Mass Spectrometry

Abstract

Gas chromatography with mass spectrometry is frequently used for the quantification of many classes of substances, including alkylphenols. Alkylphenol polyethoxylates are nonionic surfactants used in a wide variety of industrial and consumer applications. Alkylphenol polyethoxylates can degrade to alkylphenols, which are endocrine disruptors. In analytical validation procedures, the most common parameters studied are the detection and quantification limits, linearity, and recovery; however, the matrix effects are sometimes neglected. Although some investigators have evaluated matrix effects, there is no consensus on how to evaluate them during method validation. In this study, the matrix effects of alkylphenol polyethoxylates (nonylphenol monoethoxylate, nonylphenol diethoxylate, octylphenol monoethoxylate, octylphenol diethoxylate) and alkylphenols (nonylphenol and octylphenol) were studied using solid phase extraction and gas chromatography-mass spectrometry analysis. For alkylphenol polyethoxylates, the matrix effects ranged from 16 to 4692%, whereas for alkylphenols (nonylphenol and octylphenol), the effects were insignificant. Therefore, constructing an analytical curve in the matrix for alkylphenol polyethoxylates is essential.

Keywords:

• Alkylphenols
• GC-MS
• Matrix effect
• SPE
• Water

Acknowledgments

We would like to thank CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), and FACTE (Fundação de Apoio à Ciência, Tecnologia e Educação) for financial research support.

Notes

*a = linear coefficient; ** = angular coefficient

Fortification concentrations: NP = 6 µg mL⁻¹, NP1EO = 1.3 µg mL⁻¹, NP2EO = 0.7 µg mL⁻¹, OP = 1.5 µg mL⁻¹, OP1EO = 0.06 µg mL⁻¹, OP2EO = 0.06 µg mL⁻¹.

Note: For river water NP2EO cannot be analyzed due to interferences from column bleeding.

*.