title: Environmentally evaluated HPLC-ELSD method to monitor enzymatic synthesis of a non-ionic surfactant.
abstract: BACKGROUND
  N-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.
  
  
  RESULTS
  Use 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.
  
  
  CONCLUSIONS
  Use 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.
authors.affiliation: Department of Microbiology, Faculty of Pharmacy, Beni-Suef University, Salah Salem street, 62511 Beni-Suef, Egypt.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Gaber
authors.affiliation: Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
authors.forename: Cecilia Orellana
authors.initials: CO
authors.lastname: Akerman
authors.affiliation: Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
authors.forename: Rajni
authors.initials: R
authors.lastname: Hatti-Kaul
keywords: Chromatographic separation; Evaporative light scattering detector; Green analytical chemistry; HPLC-EAT; Mass spectrometry; Non-ionic surfactant