Clenbuterol cleanup

Citrinine la 69,147,148 Citronellal la 158,159 CitroneUol la 68-70,327 Citronellyl acetate la 68 Claisen-Tischenko reaction 15 54 Clathrate complex 15 303 Clavin alkaloids 15 243 Clavine alkaloids 15 246,252 Cleanup la 119 Clemastin 15 354 Clenbuterol 15 106,107,354 Clobutinol 15 354 Cloforex 15 194,296 Clomethiazole lb 354 Clomipramine 15 352,354,355 Clonacillin lb 301 Clonidine 15 354 Clopamide 15 354 Clorexolon 15321 Clotrimazol 15 98,99,401,402 Cloxacillin 1584,188 Clozapin 15 354 Cnicin 15 290... 

Unlike clenbuterol, salbutamol is a difficult compound to analyze due to its particular chemical attributes. It is a basic compound subjected to protein binding poor recoveries are obtained especially when protein precipitation techniques are used to prepare the extracts (145). In addition, salbutamol is charged at all pH values and does not readily lend itself to simple, specific back-extracting procedures. This severely restricts the options of sample cleanup. However, a Subtilisin protease digestion step followed by acid clarification and solid-phase extraction has been suggested (146) as an adequate extraction and cleanup procedure prior to the end-point determination of salbutamol by an enzyme immunoassay (139) based on the cross-reactivity of anticlenbuterol antibodies. 

Liquid-liquid partitioning cleanup is generally carried out at alkaline conditions using ethyl acetate (481, 484), ethyl acetate/tert.-butanol mixture (482), diethyl ether (478), or tert.-butylmethyl ether/n-butanol (485) as extraction solvents. The organic extracts are then either concentrated to dryness (482), or repartitioned with dilute acid to facilitate back-extraction of the analytes into the acidic solution. A literature survey shows that liquid-liquid partitioning cleanup resulted in good recoveries of substituted anilines such as clenbuterol (478, 481, 484), but it was less effective for more polar compounds such as salbutamol (482). 

Lawrence, J.F. Menard, C. Determination of clenbuterol in beef-liver and muscle-tissue using immunoaffinity chromatographic cleanup and liquid-chromatography with ultraviolet absorbency detection. J. Chromatogr. 

---