Application Note #67: Determination of Pesticides in Soil

SpeedExtractor E-916

SpeedExtractor E-916

This Application Note #67 describes a fast and reliable way to extract organochlorine pesticides (OCP) from soil with the SpeedExtractor E-916. After reducing the volume with the Syncore Analyst the extracts were cleaned by using Florisil. The cleaned extracts were concentrated again and quantified by GC-ECD.

High pressure extraction is used for a wide range of applications in environmental analysis. Recognition by the US EPA method SW-846 3545 and SW-846 6860 reflects the excellent results in comparison to classic Soxhlet extraction.

The following analytes are particularly suitable: PAH, BNA, PCB, dioxins and furanes, TPH, pesticides and many more.

Introduction:
A pesticide is any substance or mixture of substances intended for, preventing, destroying, repelling, or mitigating any pest. There are three main types of pesticides: organochlorine, organophosphate and carbamates. OCP can cause severe health problems, are persistent and tend to bio-accumulate. Therefore the use of some OCP is banned by the Stockholm convention.

Experimental:
Instrumentation: SpeedExtractor E-916 with 20 mL cells, Syncore Analyst, Thermo Trace GC Ultra
Samples: CRM 847-050 and CRM 804-050 by R.T. Corporation.

Depending on the expected values of the OCP in the samples 1 to 5g of sample were weighed and mixed with sand. The mixture was transferred to the cell and two surrogates were added prior to the extraction. The cells were extracted and 150 mL Syncore® vessels with appendix were used as collection vials.

After the extraction, 1 mL of Internal Standard (IS) was added to the extracts. After concentration on Syncore® Analyst a clean-up with Florisil was performed. The volume of the cleaned solution was reduced again and quantification of 16 different pesticides was performed by GC-ECD.

A fourfold extraction of the samples was done. Two blanks were extracted in parallel on two positions not used for samples. In addition post-extractions of the samples were to show the performance of the method.

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