Capillary electrophoresis coupled to evaporative light scattering detection for direct determination of underivatized amino acids: Application to tea samples using carboxyled single‐walled carbon nanotubes for sample preparation

Abstract

An improved and efficient method for the determination of underivatized amino acids based on the use of CE coupled to evaporative light scattering detector (ELSD), involving carbon nanotubes, was successfully developed. Carboxyled single-walled carbon nanotubes were used for the first time to perform the clean-up of the analyzed samples, which were afterwards analyzed by CE-ELSD. White tea samples were used to demonstrate the usefulness of the CE-ELSD coupled methodology. A suitable interface, based on a triple tube design sprayer, was developed and successfully used for coupling both instruments. Parameters affecting the separation and determination, including the elimination of interferences, were studied and properly optimized. Under the optimized conditions good resolution was achieved for the separation of seven amino acids. The precision of the method, expressed as RSD, was found within the 3.5-5.3% range. The LOD obtained for the proposed method were in the 1.2-2.1 pg range and the LOQ, were in the 2.0-11.5 pg range, with injection pressure of 5 KPa for 20 s (15.3 nL). This method is simple, rapid, and selective compared with other conventional techniques.

A novel approach to size separation of gold nanoparticles by capillary electrophoresis–evaporative light scattering detection

“…13,14 Very high temperatures decrease the signal of the analytes because smaller particles could enter to the detector. 13,14 Very high temperatures decrease the signal of the analytes because smaller particles could enter to the detector.…”

Interfacing commercially available capillary electrophoresis to sample preparation and/or detection systems to solve analytical problems

“…It is enough to connect a ground cable between the CE chassis and the head of the stainless steel nebulizer chamber ( Figure 6A). Our research group recently developed a method based on CE-ELSD for direct determination of underivatized aminoacids in tea samples (Bouri et al 2013a). The obtained results were positively compared with those obtained with a sophistical detector, such as MS (Soga and Heiger 2000).…”

Analytical Challenges and Metrological Approaches to Ensuring Dietary Supplement Quality: International Perspectives

“… Duong et al (2020) proposed using CE coupled with contactless conductivity detection for the determination of 10-hydroxy-2-decenoic acid and free amino acids in royal jelly supplements. CE coupled with evaporative light scattering detection has been used by Bouri et al (2013) to directly quantitate underivatized amino acids in tea samples.…”