Method Validation For Organochlorine Insecticides Determination In Ginseng By Using Isotope-Dilution Gas Chromatography-Mass Spectrometry (Id-Gc-Ms)

Organochlorine insecticides are still exploited among the most prominent pesticides for plant protection purposes. Known for having hazardous to humans and persistent in the environment properties, it is necessary to build an accurate method for detecting organochlorine insecticides in food and environmental substances. Isotope-dilution gas chromatography-mass spectrometry (ID-GC-MS) is a versatile coupling measurement system and high order method that combines both selectivity, sensitivity and high accuracy. The present paper aims at showing the methodology of the organochlorine insecticides (alpha-HCH and gamma-HCH) determination in ginseng by using ID-GC-MS. The described method covered sample preparation using an organic solvent (hexane) extraction, followed by florisil cleaning-up. After the reconstitution of the solvent base, the measurement was conducted by using ID-GC-MS in the optimal instrument parameter. Using the determined optimal conditions, the parameters such as sensitivity, linearity, precision, and accuracy were studied for validation of the ID-GC-MS method. The limit of detection and the limit of quantitation of the instrument were 0.5 ng/g and 2.0 ng/g for both analytes. The method showed linearity with the correlation coefficient of 0.999 for both alpha-HCH and gamma-HCH over the concentration range of 1-300 ng/g. The precision ranged from 3.0 to 3.7% and 2.4 to 3.3% for alpha-HCH and gamma-HCH, respectively. The mean recoveries for alpha-HCH and gamma-HCH were found at 98.0 and 95.6%, respectively. Following method validation, the measurement uncertainty of the alpha-HCH and gamma-HCH determination was evaluated according to EURACHEM GUM guide at a 95 % confidence level (k = 2). The expanded uncertainty in the measurement of alpha-HCH and gamma-HCH was 5.4% and 8.2%, respectively. All these parameters demonstrate the high sensitivity of the offered method and the success of the described method in the determination of alpha-HCH and gamma-HCH in ginseng sample.