Naslov
Solid-phase extraction for HPLC-DAD analysis of atrazine and its metabolites in water and urine

Autori
Mendaš, Gordana ; Drevenkar, Vlasta

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
14th International Symposium on Separation Science "New Achievements in Chromatography", Book of Abstracts / Šegudović, Nikola - Zagreb : Hrvatsko društvo kemijskih inženjera i tehnologa (HDKI), 2008, 81-81

ISBN
978-953-6894-36-9

Skup
14th International Symposium on Separation Science "New Achievements in Chromatography"

Mjesto i datum
Primošten, Hrvatska, 30.09.2008. - 03.10.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Atrazine; solid-phase extraction; water; urine

Sažetak
In occupationally exposed workers, atrazine and other triazine herbicides are excreted in the urine as parent compounds and their metabolites. The major urinary metabolites of atrazine found in urine samples from exposed workers were mono- and didealkylated atrazine and atrazine mercapturic acid. As the concentrations of urinary metabolites in the exposed workers are low and the concentrations of interfering compounds are high a sample pretreatment is necessary to enrich the target analyte and eliminate matrix interferences. In this study we investigated different solid-phase extraction procedures and compared them for the extraction of atrazine, three dealkylated atrazine metabolites, and atrazine mercapturate from water and human urine. We compared different sorbents - octadecylsilica (C18), styrene-divinylbenzene (SDB-1 and LiChrolut EN), silica and graphitized carbon black (Envi Carb) - and different conditioning and eluting solvents. Sample preparation was optimized for final analysis by high performance liquid chromatography with UV diode array (HPLC-UV (DAD)) detection. HPLC analysis was performed on nonpolar stationary phase based on octadecylsilica using gradient elution with phosphate buffer (pH 7) and acetonitrile as the mobile phase components. The sensitivity of the HPLC-UV (DAD) analysis ranged from 5 ng/ml for atrazine to 20 ng/ml for deethyldeisopropylatrazine in standard solutions. The ability of sorbents to retain atrazine and its metabolites was preliminary tested on spiked 5-ml water samples. Extraction recoveries of atrazine and its monodealkylated metabolites from water samples were almost quantitative (70 % - 90 %) regardless of the sorbent used. The most suitable sorbent for the extraction of atrazine mercapturate from water at mass concentrations ranging from 60 ng/ml to 984 ng/ml was octadecylsilica (recovery 93 %, RSD 11 %). Atrazine mercapturate recoveries with styrene-divinylbenzene sorbents ranged from 40 % on SDB-1 to 60 % on LiChrolut EN. Graphitized carbon black was the most efficient sorbent for the extraction of deethyldeisopropylatrazine (recovery 89 %, RSD 3 %). Silica sorbent was not suitable for the extraction of atrazine and its metabolites. The extraction procedures using octadecylsilica and styrene-divinylbenzene sorbents proved suitable for determination of atrazine and its monodealkylated metabolites in urine samples with detection limits of 15 ng/ml for deisopropylatrazine and 10 ng/ml for deethylatrazine and atrazine. None of the procedures worked for the determination of atrazine metabolites deethyldeisopropylatrazine and atrazine mercapturate in human urine because simultaneously extracted polar urine ingredients interfered with HPLC-UV (DAD) analysis of triazine compounds. Interfering polar substances were eliminated by rinsing the sorbents after urine percolation with either water-acetonitrile mixture or phosphate buffer-methanol mixture, but deethyldeisopropylatrazine and atrazine mercapturate were also completely lost during this step.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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