Pulsed electromembrane extraction for analysis of derivatized amino acids: A powerful technique for determination of animal source of gelatin samples

•An efficient method is introduced for determination of animal origin of gelatin samples.•Pulsed electric field was applied for extraction of derivatized amino acids in gelatin.•Existence of asparagine and glutamine in porcine gelatin was confirmed by HPLC-UV.•The proposed technique offered a high efficiency for trace analysis of amino acids.•Method could be carried out for differentiation of origin of gelatin in complicated media.

Differentiation of animal sources of gelatin is required for many reasons such as some anxieties about bovine spongiform encephalopathy or a ban on consuming porcine gelatin in some religions. In the present work, an efficient method is introduced for determination of animal origin of gelatin samples. The basis of this procedure is the application of pulsed electric field for extraction, preconcentration, and analysis of derivatized amino acids in gelatin. To this end, after derivatization of amino acids of interest by means of o-phthalaldehyde (OPA) for enhancing their ultraviolet (UV) absorbance as well as increasing their lipophilicities, a 137 V electric field was applied for 20 min with 10 min−1 frequency to make the analytes migrate through a 200 µm organic liquid membrane into an aqueous acceptor phase. Finally, the acceptor phase was analyzed by HPLC-UV. The proposed technique offered a high efficiency for analysis of amino acids, regarding 43% and 79% as extraction recoveries and 25 ng mL−1 and 50 ng mL−1 as limits of detection (LODs) for asparagine and glutamine, respectively. Therefore, due to sample cleanup ability of the proposed method and obtained preconcentration factors (29 and 53 for asparagine and glutamine, respectively), it could be carried out for differentiation of animal origins of gelatin samples, even if only small amounts of samples are available or in complicated media of foodstuffs and medicament.

Graphical abstractAn efficient method is introduced for the first time, for determination of animal origin of gelatin samples. The basis of this procedure is application of pulsed electric field for extraction and preconcentration of derivatized amino acids in gelatin followed by analysis of them with HPLC-UV.Figure optionsDownload full-size imageDownload as PowerPoint slide