Identification of dried shark fins by analysis of seven sugars using pre-column derivatization high-performance liquid chromatography and stable carbon isotope ratio analysis

Abstract

A simple and sensitive method using pre-column high-performance liquid chromatography (HPLC) was developed for the simultaneous detection of seven sugars, which was also applied for the preliminary identification of dried shark fins. δ¹³C values of the dried shark fin samples also were determined by element analyser-isotope ratio mass spectrometry (EA-IRMS). The dried shark fins were decomposed by enzymolysis using a papaya protease and an amylase enzyme; then, samples were analysed by HPLC after the derivatization of the enzymatic hydrolysate, using 1-phenyl-3-methyl-5-pyrazolone (PMP) as the derivatizing agent. The results indicated that the seven sugars were well separated by this method. Of the conditions tested, application of a derivatization time of 75 minutes and of a phosphate buffer–acetonitrile (80 : 20, v/v) mobile phase system (pH = 6.8) yielded the best detection results and separation effects of the seven standard substances. Note that the areas under the peaks of two kinds of uronic acid derivative products decreased significantly (P < 0.01) with time, so it is necessary to perform the HPLC analysis within 24 h after the derivatization reaction. The developed method is suitable for the identification and analysis of artificial dried shark fins with good accuracy, reproducibility and sensitivity. In addition, δ¹³C values were highly significant (P < 0.01) for real and fake dried shark fins. Thus, the combination of these methods could potentially be useful for identification of dried shark fins regardless of whether they are fake or artificial.