Environmentally evaluated HPLC-ELSD method to monitor enzymatic synthesis of a non-ionic surfactant

Abstract

BackgroundN-Lauroyl-N-methylglucamide is a biodegradable surfactant derived from renewable resources. In an earlier study, we presented an enzymatic solvent-free method for synthesis of this compound. In the present report, the HPLC method developed to follow the reaction between lauric acid/methyl laurate and N-methyl glucamine (MEG) and its environmental assessment are described.ResultsUse of ultraviolet (UV) absorption or refractive index (RI) detectors did not allow the detection of N-methyl glucamine (MEG). With Evaporative light scattering detector ELSD, it was possible to apply a gradient elution, and detect MEG with a limit of detection, LOD = 0.12 μg. A good separation of the peaks: MEG, lauric acid, product (amide) and by-product (amide-ester) was achieved with the gradient program with a run time of 40 min. The setting of ELSD detector was optimized using methyl laurate as the analyte. LC-MS/MS was used to confirm the amide and amide-ester peaks. We evaluated the greenness of the developed method using the freely available software HPLC-Environmental Assessment Tool (HPLC-EAT) and the method got a scoring of 73 HPLC-EAT units, implying that the analytical procedure was more environmentally benign compared to some other methods reported in literature whose HPLC-EAT values scored up to 182.ConclusionUse of ELSD detector allowed the detection and quantification of the substrates and the reaction products of enzymatic synthesis of the surfactant, N-lauroyl-N-methylglucamide. The developed HPLC method has acceptable environmental profile based on HPLC-EAT evaluation.

Development of the HPLC–ELSD method for the determination of phytochelatins and glutathione inPerilla frutescensunder cadmium stress conditions

“…The MS method is the most effective, but this detector is quite expensive. The evaporative light-scattering detector (ELSD) is a universal mass detector that has been widely applied in many fields, such as food analysis, pharmaceutical analysis and environmental analysis [22][23][24]. ELSD can be applied to quantitatively detect solutes which should have a higher volatility than the mobile phase via the detection of light scattering changes.…”

Oyster mushroom’s lipase enzyme entrapment on calcium alginate as biocatalyst in the synthesis of lauryl diethanolamide

“…The product of the amidation reaction between lauric acid and diethanolamine was characterized using HPLC [8]. The peak of lauryl diethanolamide appears at a retention time of 9.22 min with a concentration 22.91%.…”

One‐Step Biocatalytic Synthesis of Sustainable Surfactants by Selective Amide Bond Formation**

“…[4,7] These lipase-catalyzed reactions using Nmethyl-D-glucamine (1) and either a fatty acid or a fatty acid methyl ester yield a mixture of amide (target product) and ester by-products, which can react with the acyl donor a second time to form an amide-ester, which is reported to be the major by-product. [5] As amide bonds are prevalent motifs in many natural products and pharmaceuticals, there has been growing interest in the development of aqueous amidation methods under benign conditions. [8] Biocatalysts, in particular ATPdependent enzymes, have gained increasing interest over recent years.…”