Semi-permeable surface analytical reversed-phase column for the improved trace analysis of acidic pesticides in water with coupled-column reversed-phase liquid chromatography with UV detection: Determination of bromoxynil and bentazone in surface water

摘要: Abstract The coupled-column (LC–LC) configuration consisting of a 3 μm C 18 column (50×4.6 mm I.D.) as the first and 5 semi-permeable-surface (SPS) (150×4.6 second appeared to be successful for screening acidic pesticides in surface water samples. In comparison LC–LC employing two columns, combination /SPS-C significantly decreased baseline deviation caused by hump co-extracted humic substances when using UV detection (217 nm). developed procedure allowed simultaneous determination target analytes bentazone bromoxynil uncleaned extracts samples level 0.05 μg/l less than 15 min. with simple solid-phase extraction step (200 ml on 500 mg -bonded silica) analytical provides high sample throughput. During period about five months more 200 ditch-water originating from agricultural locations were analyzed procedure. Validation method was performed randomly analyzing recoveries spiked at levels 0.1 ( n =10), 0.5 =7) 2.5 =4). Weighted regression recovery data showed that overall 95 100% bromoxynil, respectively, corresponding intra-laboratory reproducibilities 10 11%, respectively. Confirmation part carried out GC–negative ion chemical ionization MS involving derivatization bis(trifluoromethyl)benzyl bromide. No false negatives or positives observed.