Simultaneous determination of anionic, amphoteric and cationic surfactants mixtures in surface water

A simple, reliable and accurate HPLC/CAD method was developed for the determination of anionic (sodium
dioctyl sulfosuccinate and sodium 1-dodecane sulfonate), amphoteric (CHAPS (3-[(3-Cholamidopropyl)
dimethylammonium]-1-propanesulfonate hydrate)) and cationic (benzethonium chloride) surfactants
mixture from surface water samples. The chromatographic analysis was performed on an Acclaim Surfactant
Plus (150 x 3.0 mm, 3µm d.p.) column acquired from Thermo Scientific, kept at 300C. All experiments were
performed in gradient elution conditions at a flow-rate of 0.6 mL/min. Mobile phase composition was a
mixture of acetonitrile (A) and 0.1 M ammonium acetate solution acidified to pH 5 with acetic acid (B). The
limit of detection (LD) were 20µg/L for anionic surfactants and 30µg/L for cationic and amphoteric
surfactants. The calibration curves were linear between 15 mg/L – 110 mg/L, with R2 values above 0.992 for
all surfactants. Solid phase extraction (SPE) using polymeric (Strata X) cartridges has been applied to
extract and concentrate the target analytes from the synthetic samples. Surfactants recoveries after SPE
procedure were situated between 91.5÷94.6%. Intra-day and inter-day precision (RSD%) were situated
between 4.0 ÷ 7.7% and 7.5 ÷ 11.7%, respectively. Limit of quantitation (LQ) was lower than 80µg/L for
anionic surfactants and 90µg/L for cationic and 100µg/L for amphoteric surfactants. The new sensitive and
selective HPLC/CAD developed method allows simultaneous determination of anionic, amphoteric and
cationic surfactants mixture from environmental samples (surface water).