β2-Agonist extraction procedures for chromatographic analysis

Normally, different procedures were necessary to prepare sample matrices for chromatographic determination of β2-agonists. The present review includes sampling, pre-treatment and extraction/purification for urine, plasma, liver, meat, feeds, hair and milk powder, as previous steps for chromatographic analysis of β2-agonists. Six methodologies were especially revised for extraction/purification namely, liquid–liquid extraction, solid-phase extraction (SPE), matrix solid-phase dispersion, immunoaffinity chromatography, dialysis and supercritical fluid extraction. SPE was discussed in detail and five mechanisms were described: adsorption, apolar, polar, ion-exchange and mixed phase. A brief conclusion in this field was also outlined.