engleski

Determination of triazine herbicides and their metabolites in urine

Triazine compounds in biological and environmental samples are most often determined by high-performance liquid chromatography with UV detection or gas chromatography with nitrogen selective or mass selective detection. Due to the high concentrations of interfering compounds the analysis of urinary triazines should include separation of target compounds from the matrix and their efficient enrichment by solvent or solid phase extraction. In this work an HPLC-UV method was developed to determine triazine herbicides atrazine, simazine, prometryn, ametryn, and atrazine monodealkylated metabolites in human urine. The triazine compounds were accumulated from urine by passing 5 mL samples through a styren-divinylbenzen (SDB) cartridge. The retained polar interferences were eliminated by washing the cartridge with a water-acetonitrile mixture and the triazine compounds were eluted with acetone. For HPLC-UV analysis the acetonic eluate was evaporated and the dry residue was redissolved in 2 mL of water. The analysis was performed on a 25 x 0.4 cm i.d RP-ODS column using gradient elution with phosphate buffer (pH=7) and acetonitrile as the mobile phase. The detection limit of parent compounds and atrazine metabolites in urine was 10 and 20 ng/mL, respectively. The method showed linearity over the concentration range in urine of up to 1000 ng/mL for triazine herbicides and 2000 ng/mL for deethylatrazine and deisopropylatrazine. The solid-phase extraction recoveries were 96%, 78%, 94%, 99%, 95% and 93% and standard deviations were 9, 12, 6, 4, 5, and 6% for deethylatrazine, deisopropylatrazine, atrazine, simazine, ametryn and prometryn, respectively. The HPLC-UV method was not suitable for determination of didealkylated atrazine which was assumed to be lost from the SDB cartridge during the washing out step. We also tested the SDB extraction efficiency and detection sensitivity of urinary triazine compounds, including deethyldeisopropylatrazine, by GC analysis of acetonic eluate on a 60 m x 0.25 mm SPB-5 capillary column using the nitrogen selective detection.

Atrazine; simazine; prometryn; ametryn; atrazine monodealkylated metabolites; urin

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