Determination of Abamectin Residue in Paprika by High-Performance Liquid Chromatography

Abstract

Reversed-phase high-performance liquid chromatography (HPLC) techniques were developed to quantify abamectin (ABM) in paprika ( Capsicum annum ). Separation was achieved on a C 18 ODS column with a mobile phase of acetonitrile/water (96/4 v/v) mixture in an isocratic elution at the flow rate of 1.2 , ,, , mL/min for avermectins (AVMs). The retention times were 8.0 and 9.7mins for AVM B 1b and AVM B 1a , respectively. Residual AVMs (sum of AVM B 1a , AVM B 1b and 8,9-Z-AVM B 1a ) in the vegetable were ext- racted with acetonitrile, and the silica solid-phase extraction cartridges were used to purify the extracts. AVMs were derivatized using trifluoroacetic acid and 1-methylimidazole, and the derivatives were determined with a fluorescence detector (excitation at 365 nm and emission at 470 nm). High and consistent recoveries, ranging from 93% to 115%, were obtained for AVM B 1a and 8, 9-Z-AVM B 1a at fortified levels of 20 g/kg and μμ μ 200 g/kg for paprika. The limit of quantitation (LOQ) was 2 g/kg. The residual levels of AVMs in pap μ μ μ μ μ μ μ μ - rika in a field experiment from one day to seven days after the last application decreased from 18.40 to 7.59 g/kg. The half-life (T μμ μ 1/2 ) of AVMs in paprika was 1.47 days.