Hydroxyproline Measurement by HPLC: Improved Method of Total Collagen Determination in Meat Samples

A sensitive and selective assay of hydroxyproline is presented for the determination of collagen in meat and meat products. The amino acid is converted to a sensitive fluorescent derivative with 7‐chloro‐4‐nitrobenzofurazan (NBD‐Cl), followed by reversed‐phased chromatography and fluorescence measurement (ex = 465 nm, fl = 535 nm). Hydroxyproline and proline can be measured by this system. The column and detector performance shows good retention, selectivity, and efficiency. Based on replicated analysis of controls over a range of 0–20 mg/mL, the method is accurate (94–100%) and precise (%CV of 0.3–13). The limit of quantification for hydroxyproline and proline was 0.0027 ng/mL. Fourteen meat samples with different levels of collagen normally found in meat and meat products were tested. The results showed that the linear range of assay was suitable for routine analysis, and applicable to the entire range of hydroxyproline levels normally found in meat and meat products (0.05–12.5%).