Development and validation of a liquid chromatography isotope dilution mass spectrometry method for the reliable quantification of alkylphenols in environmental water samples by isotope pattern deconvolution

• Published in: Journal of Chromatography A 2014-02, Vol.1328, p.43-51
• Main Authors: Fabregat-Cabello, Neus, Sancho, Juan V., Vidal, Andreu, González, Florenci V., Roig-Navarro, Antoni Francesc
• Format: Article
• Language: English
• Subjects: Alkylphenol; Analytical chemistry; Applied sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Deconvolution; Dilution; Exact sciences and technology; Extraction; Hafnium; Hollow fiber liquid phase microextraction; Isotope dilution mass spectrometry; Isotope pattern deconvolution; Isotopes; LC–MS/MS; Mass spectrometry; Measurement methods; Methodology; Other chromatographic methods; Other wastewaters; Pollution; Wastewater analysis; Wastewaters; Water treatment and pollution
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2013.12.077

•We determined NP and 4-t-OP combining isotope dilution mass spectrometry (IDMS) and isotope pattern deconvolution (IPD).•Matrix effect compensation based on IDMS methodology and the minimal labeled standard was used which avoids isotopic effects.•In-house synthesis and characterization of the isotope-marked compound 13C1-4-tert-octylphenol.•A hollow-fiber liquid phase microextraction procedure offers a cheap and easy extraction of alkylphenols from water samples.•Full validation of the proposed HF-LPME-UHPLC–MS/MS methodology in wastewater samples. We present here a new measurement method for the rapid extraction and accurate quantification of technical nonylphenol (NP) and 4-t-octylphenol (OP) in complex matrix water samples by UHPLC-ESI-MS/MS. The extraction of both compounds is achieved in 30min by means of hollow fiber liquid phase microextraction (HF-LPME) using 1-octanol as acceptor phase, which provides an enrichment (preconcentration) factor of 800. On the other hand we have developed a quantification method based on isotope dilution mass spectrometry (IDMS) and singly 13C1-labeled compounds. To this end the minimal labeled 13C1-4-(3,6-dimethyl-3-heptyl)-phenol and 13C1-t-octylphenol isomers were synthesized, which coelute with the natural compounds and allows the compensation of the matrix effect. The quantification was carried out by using isotope pattern deconvolution (IPD), which permits to obtain the concentration of both compounds without the need to build any calibration graph, reducing the total analysis time. The combination of both extraction and determination techniques have allowed to validate for the first time a HF-LPME methodology at the required levels by legislation achieving limits of quantification of 0.1ngmL−1 and recoveries within 97–109%. Due to the low cost of HF-LPME and total time consumption, this methodology is ready for implementation in routine analytical laboratories.