Shimadzu has produced an application note describing an example of using the Nexera UC online SFE-SFC-MS system to analyze residual pesticides in agricultural products.
Introduction
The Nexera UC online SFE-SFC-MS system combines supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) in one online system, so that the entire process from extraction of target components to acquisition of data can be performed completely automatically. Furthermore, the system can add polar organic solvents (modifiers) to the supercritical carbon dioxide fluid during SFE and SFC, so that the system can be used to extract and analyze components with a wide range of polarities.
Sample Preparation
QuEChERs is a well-known method used to pretreat agricultural products for residual pesticide analysis. However, the method requires many steps including adding reagents, solvent extraction and centrifugal separation. In contrast, the online SFE-SFC-MS system only requires mixing 1 g of agricultural product crushed with a mixer with 1 g of a dehydrating agent and placing the mixture in an extraction vessel. Using a dedicated rack changer, the system can continuously extract and analyze up to 48 samples at a time.
Analysis of Standard Mixture of Pesticides
The standard mixture sample of 510 pesticide components were mixed with a dehydrating agent and analyzed using the analytical conditions described in the application note. The entire process from extraction to data acquisition took approximately 45 minutes per analysis. For 327 components, good repeatability for the concentration range from 1 to 100 ng/g (less than 30% RSD for relative standard deviation for peak area at respective concentrations) and good linearity (contribution ratio of at least R2 = 0.99) was obtained.
Conclusion
The Nexera UC online SFE-SFC-MS system is shown to provide an effective method for residual pesticide analysis improving analytical productivity, reducing the environmental impact and avoiding human errors involved in pretreatment steps.
