Online Sequential-Injection Chromatography with Stepwise Gradient Elution: A Tool for Studying the Simultaneous Adsorption of Herbicides on Soil and Soil Components

Autor(es)

Urio, Ricardo de Pra ^[1] ; Infante, Carlos M. C. ^[1] ; Masini, Jorge C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, BR-05513970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Agricultural and Food Chemistry; v. 61, n. 33, p. 7909-7915, AUG 21 2013.
• Citações Web of Science: 7

Resumo

The adsorption of triazine herbicides simazine (SIM), atrazine (ATR), and propazine (PRO) as well as the metabolites deisopropylatrazine (DIA), deethylatrazine (DEA), and 2-hydroxyatrazine (HAT) on soil, humic acid, and soil modified with humic acidic was studied by sequential-injection chromatography with UV detection at 223 nm. An online monitoring system was assembled, which was composed of a tangential filter and a peristaltic pump for the circulation of the soil (25 g L-1) or humic acid (2.5 g L-1) suspensions. A stepwise gradient elution separated the compounds using three mobile phases whose compositions were 28, 40, and 50% (v v(-1)) methanol in 1.25 mmol L-1 ammonium acetate buffer, pH 4.7. The sampling throughput was about six analyses per hour; the linear dynamic range was between 100 and 1000 mu g L-1 for all of the studied compounds. The detection limits varied from 9 mu g L-1 for ATR to 36 mu g L-1 for DEA. At contact times <2 h, humic acid was the material with a higher adsorptive capacity (from 1470 +/- 43 mu g g(-1) for DIA to 2380 +/- 51 mu g g(-1) for PRO). In soil, HAT exhibited the highest adsorption (23.8 +/- 0.2 mu g g(-1)). The presence of humic acid in the soil increased the adsorption of ATR (14 +/- 1 to 23 +/- 2 mu g g(-1)) and PRO (21.5 +/- 0.5 to 24.0 +/- 0.2 mu g g(-1)), decreased the adsorption of HAT (23.8 +/- 0.2 to 18 +/- 2 mu g g(-1)), and did not affect DIA and DEA. The adsorption of SIM was negligible in all of the sorbents studied. Simazine is the herbicide with the greatest potential for leaching to water bodies followed by DEA and DIA. (AU)

• Processo FAPESP: 11/08309-5 - Desenvolvimento e avaliação de métodos de extração e separação cromatográfica para determinação de herbicidas triazínicos, uréias e uracilas em amostras de solos e águas
• Beneficiário: Ricardo de Prá Urio
• Linha de fomento: Bolsas no Brasil - Doutorado