A micellar electrokinetic capillary chromatography (MEKC) method employing
sodium dodecil sulfate (SDS) as the surfactant has been developed to separa
te and to quantificate simazine, aziprotryne, hexazinone, and diuron in env
ironmental water samples.
Good linearity was obtained between normalized peak area and standard solut
ion concentration for all studied compounds (concentration range: 0.1 to 5.
0 mug/mL). The detection limit was lower than 6 pg (loaded into the capilla
ry a 35 muL of sample volume) for all herbicides.
The optimized MEKC method after a 1000-fold concentration step by solid-pha
se extraction (SPE) was applied to determine these herbicides in environmen
tal water samples. Herbicide concentrations lower than 0.1 ng/mL can be mea
sured, and can have a relative standard deviation of about 4.0%. Simazine w
as detected at concentrations around 1.0 to 2.0 ng/mL in the Alberche and T
ajuna river waters. The highest concentration appeared in the Tajuna river.
The presence of simazine in both river waters was contrasted with gas chro
matography coupled to mass spectrometry analysis. The quantification of the
samples was contrasted with immunochemical assays, obtaining good correlat
ion between this and MEKC results.