GC-MS Determination of 3 Alkylphenols in Water with Stirring Rod Adsorptive Extraction and Thermal Desorption

GC-MS was applied to the determination of 3 alkylphenols, i.e. n-octylphenol, t-octylphenol and n-nonylphenol in water with stirring rod adsorptive extraction and thermal desorption. The water sample was adjusted to pH 3.0 with HCl, an aliquot of 10.00 mL was transferred into the head-space flask and extracted with stirring rod adsorption. The stirring rod was removed out and put on the thermal desorption tube and the desorbed analytes were introduced into the instrument by the CIS4 sampling system and separated on DB-5MS column. MS determination was carried out under full-scanning mode (for qualitative analysis) and selected ion monitoring mode (for quantitative analysis). Linear relationships between values of peak area and mass concentration of 3 alkylphenols were kept in the same range of 5-200 ng·L-1, with detection limits (3S/N) in the range of 1.2-2.5 ng·L-1. Recovery was tested by standard addition method using substantial water samples as matrixes, giving values of recovery and RSD′s (n=5) in the ranges of 95.0%-118% and 0.90%-10% respectively.