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Dispersive liquid-liquid microextraction for rapid and inexpensive determination of tetramethylpyrazine in vinegar
Jianhai Wu1, Hongbo Zhao1, Ming Du1
1National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
Abstract:
The concentration of tetramethylpyrazine (TMP) in vinegar is an active indicator of vinegar quality. Dispersive liquid-liquid microextraction (DLLME) was first applied to vinegar as a clean-up pre-treatment for the rapid (5 min) determination of TMP by high-pressure liquid chromatography with ultraviolet detection (HPLC-UV), and may serve as an alternative to solid-phase extraction (SPE) or solid-phase microextraction (SPME). High sensitivity of HPLC for TMP determination was obtained using the DLLME pretreatment, with a limit of detection (LOD) of 0.001 mg L-1 and limit of quantification (LOQ) of 0.005 mg L-1. The developed method exhibited excellent linearity in the concentration range of 0.050-80.000 mg L-1, with a correlation coefficient R2 > 0.999. Furthermore, the percentage recovery of TMP in vinegar using the developed method was within the range 97.97-105.24%. Therefore, DLLME coupled with HPLC-UV is a sensitive and promising method for vinegar clean-up and TMP assay.
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