Multiple reaction monitoring for the accurate quantification of amino acids: using hydroxyproline to estimate collagen content.

Multiple reaction monitoring (MRM) mass spectrometry may be regarded as the gold standard methodology for quantitative mass spectrometry and has been adopted for the analysis of small molecules especially within the pharmaceutical industry. It can also be applied to the analysis of peptides and proteins and to the measurement of the basic building blocks of proteins, amino acids. Here, we describe the application of MRM mass spectrometry to the measurement of hydroxyproline after acid hydrolysis of various animal tissues. We show that the measurement of hydroxyproline provides an accurate and reliable estimate of the collagen content of such tissues and may be a useful indicator of meat tenderness.