Extraction of incurred sulphamethazine in swine tissue by microwave assisted extraction and quantification without clean up by high performance liquid chromatography following derivatization with dimethylaminobenzaldehyde*

Abstract

A rapid and reliable method using microwave energy is described for the extraction of spiked and incurred (freeze‐dried and fresh) sulphamethazine residues from swine tissues/organs (muscle, liver and kidney). Incurred tissues were obtained from an abattoir and freeze‐dried pig tissue reference materials were produced as part of a reference material study for the Community Bureau of References, European Communities. The extraction was achieved by irradiating the sample in methanol for 25 s in a household microwave oven, commonly referred to as microwave‐assisted extraction (MAE). The extracts were analysed without clean‐up by high performance liquid chromatography (HPLC) using a C18column and detected at 450 nm after derivatization with 4‐dimethylaminoben‐zaldehyde (DMABA) in a heated rector at 40°C. The limit of quantitation was 2.5μg kg−1 of wet tissues. A comparison of MAE with an homogenization technique indicated that MAE worked extremely well for freeze‐dried samples, while it showed significant variation for wet tissues. No sulphamethazine was detected in retail pork meat and liver samples when analysed by the MAE technique.traction of incurred sulphamethazine in swine tissue by microwave assisted extraction and quantification without clean up by high performance liquid chromatography following derivatization with dimethylaminobenzaldehyde