Quantification of the b2-adrenergic feed additives ractopamine and salbutamol by reductive amination–assisted modification

Abstract

b2-Adrenergic compounds such as ractopamine and salbutamol can cause smooth muscle relaxation and are used for asthma and chronic obstructive pulmonary disease treatment. However, b2-adrenergic compounds may also cause some adverse cardiovascular effects or behavioral changes in humans; therefore, it is important for analytical chemists to determine the amounts of b2-adrenergic compounds in raw biological materials. Herein, novel analogs for standards and internal standard analogs were synthesized through reductive amination with isotopic H2-formaldehyde, D2-formaldehyde, and sodium cyanoborohydride. These analogs were used for quantifying b2-adrenergic compounds such as ractopamine and salbutamol in ground pork samples under multiple reaction monitoring scanning modes by tandem mass spectrometry. H2-Formaldehyde– modified ractopamine and H2-formaldehyde–modified salbutamol acting as standards were used to prepare calibration curves, whereas D2-formaldehyde was used to generate D2-modified ractopamine and D2-modified salbutamol analogs acting as internal standards. The H2-modified ractopamine and H2-modified salbutamol showed excellent correlation coefficients, limits of detection, and limits of quantification. In mass spectrometric detection, H2-modified ractopamine showed 202% signal enhancement after modification and H2-modified salbutamol showed 17% signal enhancement after modification.