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

• Published in: Journal of agricultural and food chemistry 2013-08, Vol.61 (33), p.7909-7915
• Main Authors: de Prá Urio, Ricardo, Infante, Carlos M.C, Masini, Jorge C
• Format: Article
• Language: English
• Subjects: Adsorption; ammonium acetate; atrazine; Atrazine - chemistry; Automation - instrumentation; Automation - methods; Biological and medical sciences; chromatography; Chromatography - instrumentation; Chromatography - methods; detection limit; Food industries; Fundamental and applied biological sciences. Psychology; Herbicides - chemistry; humic acids; leaching; methanol; propazine; simazine; Simazine - chemistry; soil; Soil - chemistry; Soil Pollutants - chemistry; surface water; Triazines - chemistry
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf402447n

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 μg L–1 for all of the studied compounds. The detection limits varied from 9 μg L–1 for ATR to 36 μg L–1 for DEA. At contact times