Determination of the New Food Ingredient Pyrroloquinoline Quinone Disodium Salt in Foods by Centrifugal Ultrafiltration Coupled with High Performance Liquid Chromatography

This study established a method for the determination of pyrroloquinoline quinone (PQQ) disodium salt, a newly approved food ingredient in China, in foods using centrifugal ultrafiltration as a novel pretreatment technique combined with high performance liquid chromatography (HPLC). Ethylenediaminetetraacetic acid disodium (EDTA-2Na) solution was used as a stabilizing agent in sample extraction. After purification by centrifugal purification, chromatographic separation was accomplished on a RD-C₁₈ column (4.6 mm × 150 mm, 5 μm) with gradient elution using a mobile phase consisting of tetrabutylammonium bromide-potassium dihydrogen phosphate mixed solution and acetonitrile. Detection was carried out using a photodiode array detector. The calibration curve showed good linearity within the concentration range of 0.0400–10.0 mg/L with a determination coefficient of 0.9998. The limit of quantitation (LOQ) was 1.0 mg/kg for liquid samples and 4.0 mg/kg for soy sauce, semi-solid, and solid samples. The recoveries from spiked samples ranged from 82.1% to 103.3% with a relative standard deviation (RSD) ranging from 0.7% to 2.5%. This method was characterized by high sensitivity, simple operation, rapidity and accurate and reliable quantification, and suitable for the quantitative detection of PQQ disodium salt in various food matrices. This research effectively addresses the shortcomings of existing methods for detecting PQQ disodium salt in foods and provide strong technical support for the routine supervision of PQQ disodium salt in various food matrices.