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Comparative Study of the Determination of Parabens in Shampoos by Liquid Chromatography with Amperometric and Coulometric Detection
Author(s) -
Murakami Kazuo,
Watanabe Hayaki,
Tateno Tsuyako,
Kauffmann JeanMichel
Publication year - 2010
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201000042
Subject(s) - chemistry , chromatography , detection limit , amperometry , analyte , acetic acid , coulometry , elution , methanol , liquid chromatography–mass spectrometry , mass spectrometry , electrochemistry , electrode , organic chemistry
The simultaneous determination of four para ‐hydroxybenzoic acid esters (parabens) in shampoos was studied by liquid chromatography (LC) with amperometric (LC‐AD) and coulometric (LC‐CD) detection. The parabens were separated on an ODS C18 reversed column by isocratic elution with a mobile phase based on methanol‐0.1 M acetic acid (60 : 40%, v/v) with 0.02 M NaClO 4 at a flow rate of 0.8 mL min −1 . The limit of detection ( S / N >3) for the analytes was in the 15–25 pg (injected mass) range at an applied potential of 1.20 V vs. Ag/AgCl using the LC‐AD and in the 2–3 pg range at a potential of 0.790 V vs. Pd using the LC‐CD. The peak ratio of the internal standard peak (IS: 4‐hydroxybenzoic acid sec‐butyl ester) versus the analyte peak was found to be related to the amount injected from 0.1 ng to 100ng ( r =0.996–0.999) with the LC‐AD and from 0.050 ng to 100 ng range ( r =0.999–1.000) with the LC‐CD. The relative standard deviation ( RSD, n =10) was comprised between 1.8 to 3.5% by LC‐AD ( 5 ng injected) and between 2.0 to 2.4% by LC‐CD (0.5 ng injected). The determination of four most used parabens in ten different shampoos was successfully realized.