Differentiating Trachemys scripta elegans Shell Glue from Chinemys reevesii Shell Glue by UPLC-QTOF/MS Coupled with Binary Compare Tool of UNIFI

Abstract

Objective: This study was conducted to develop an method for identification of Trachemys scripta elegans (Ba Xi Gui, 巴西龟) shell glue from Chinemys reevesii (Zhong Hua Cao Gui, 中华草龟) shell glue. Methods: In this research, an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) method coupled with Binary Compare tool of UNIFI software was validated to differentiate Trachemys scripta elegans (Ba Xi Gui, 巴西龟) shell glue from Chinemys reevesii (Zhong Hua Cao Gui, 中华草龟) shell glue. The gelatins were digested enzymatically into peptides using trypsin.The UPLC-QTOF/MS data of the trypsin digested samples was subjected to Binary Compare of UNIFI software in order to screen out the unique peptides. PEAKS® Studio software was utilized to identify the sequence of the marker peptides. Results: It was found that m/z 641.3 was the marker peptide in samples of Trachemys scripta elegans (Ba Xi Gui, 巴西龟) shell glue, and m/z 649.3 was the marker peptide in samples of Chinemys reevesii (Zhong Hua Cao Gui, 中华草龟) shell glue, with possible amino acid sequence of GEAGPSGPAGPTGAR and GESGPSGPAGPTGAR respectively. Conclusions: The results will be helpful for the differentiating between these 2 gelatins, and it can be also used for quality control of Tortoise shell glue (Gui Jia Jiao, 龟甲胶). Keywords: UPLC-QTOF/MS, Tortoise shell glue, Trachemys scripta elegans (Ba Xi Gui, 巴;西;龟), Chinemys reevesii (Zhong Hua Cao Gui, 中;华;草 龟)