The document describes the sample preparation method using 0.1 N HCl for extracting beta-agonists from vitreous humor and retina extracts of pigs. However, under strong acidic conditions, the beta-agonists are protonated and not well retained on reversed phase SPE sorbents. To improve recovery, the pH of the acidic sample extract needs to be adjusted to basic conditions, which is time-consuming. High SPE recoveries can be achieved using Bond Elut Plexa PCX, which does not require pH adjustment and offers time savings. The polymeric sorbent combines reversed phase with strong cation-exchange functionalities and binds the basic analytes under acid conditions. Recoveries for many compounds can be improved to >90%. Additionally, Bond Elut Plexa PCX reduces ion suppression and minimizes binding of proteins and lipids due to its highly polar, hydroxylated polymer surface.
This document details an improved sample preparation method for testing veterinary drug residues, specifically growth-promoting beta-agonists, in pig vitreous humor and retina extracts. The method utilizes Bond Elut Plexa PCX, a mixed-mode polymeric sorbent with strong cation-exchange functionality, to concentrate basic analytes under acidic conditions without requiring pH adjustment. This approach eliminates neutral and acidic interferences, reduces ion suppression, and improves analytical recovery and sensitivity compared to traditional reversed phase SPE methods.
The method extracts and measures Cenbuterol, Clenproperol, Cimbuterol, Cyclohexylelenbuterol, Brombuterol, Tulobuterol, Fenoterol, Propanolol, Terbutaline, and Clenbuterol D9.
The procedure requires applying 20 mL of 0.1 N HCl to 2 g of vitreous humor and retina sample.
The sample must be centrifuged at 10 °C with 12000 rpm.