Development and validation of a HILIC-UPLC-ELSD method based on optimized chromatographic and detection parameters for the quantification of polyols from bioconversion processes

Abstract

Crude glycerol is a by-product of biodiesel production and nowadays has low commercial value for chemical industries. Biotechnological processes may be used to transform this by-product into diverse value-added chemical compounds. In this context, a representative analytical protocol to monitor the production of chemicals from bioprocesses is mandatory. This study presents a novel, simple and fast method developed, validated and based on ultra-high performance liquid chromatography (UPLC) with evaporative light scattering detection (ELSD) using a hydrophilic interaction chromatography column (HILIC) to identify and quantify glycerol, arabitol and mannitol during bioconversion of crude glycerol. Under optimized conditions, these three target analytes were baseline separated with 6 min. Limits of detection (LOD) and quantification (LOQ) ranged from 5.0 to 8.0 and 13.0 to 18.0 ng, respectively. The method showed good precision, stability, repeatability and recovery. Polyols exhibited a regression relationship to the log–log function (R > 0.999) within the concentration ranges from 5.0 to 2000.0 μg mL⁻¹. Average recoveries covering four points were within the range of 94.6–101.7% with the coefficient of variation being ≤3.1% for the three analytes. The intra- and inter-assay precisions were less than 3.9%. This method was successfully applied to real samples obtained after bioconversion of crude glycerol. The developed method was simpler, faster and more sensitive than the conventional HPLC-RID protocol. Thereby, this new method based on HILIC-UPLC-ELSD represents an important analytical protocol for monitoring glycerol conversion in biotechnological processes and helps to select promising microorganisms during bioprospection studies.