CE‐UV for the characterization of passion fruit juices provenance by amino acids profile with the aid of chemometric tools

Abstract

A separation method was developed in order to quantify free amino acids in passion fruit juices using CE-UV. A selective derivatization reaction with FMOC followed by MEKC analysis was chosen due to the highly interconnected mobilities of the analytes, enabling the separation of 22 amino acids by lipophilicity differences, as will be further discussed. To achieve such results, the method was optimized concerning BGE composition (concentrations, pH, and addition of organic modifier) and running conditions (temperature and applied voltage). The optimized running conditions were: a BGE composed by 60 mmol/L borate buffer at pH 10.1, 30 mmol/L SDS and 5 % methanol; running for 40 min at 23°C and 25 kV. The method was validated and applied on eight brands plus one fresh natural juice, detecting 12 amino acids. Quantification of six analytes combined with principal component analysis was capable to characterize different types of juices and showed potential to detect adulteration on industrial juices. Glutamic acid was found to be the most concentrated amino acid in all juices, exceeding 1 g/L in all samples and was also crucial for the correct classification of a natural juice, which presented a concentration of 22 g/L.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

“…The low cost, and the generation of low number of by‐products are the main advantages of this derivatization reagent. Another CE‐UV method based on micellar electrokinetic chromatography (MEKC) was developed to quantify 22 free AAs in passion fruit juices . This time, a selective derivatization reaction with 9‐fluorenylmethoxycarbonylchloride (FMOC) was used.…”

Recent advances in amino acid analysis by capillary electromigration methods: June 2015–May 2017

“…Twelve AAs from passion fruits were also studied in MEKC‐UV after labelling with FMOC, and detect at 265 nm. A principal component analysis revealed that MEKC‐UV allows characterizing different types of juices by measuring the concentrations of 6 AAs .…”

Advances in the Determination of Nonprotein Amino Acids in Foods and Biological Samples by Capillary Electrophoresis

“…Fluorescence detection has also been widely employed for the analysis of NPAAs due to its high sensitivity; however, a derivatization procedure is also needed due to the lack of fluorescence of most amino acids. Many derivatization reagents such as 2,3-naphthalenedicarboxaldehyde (NDA) [9,10,11,12,13,14], 4fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) [15,16,17,18], fluorescein isothiocyanate (FITC) [19], 9-fluorenylmethyl chloroformate (FMOC-Cl) [20], benzoyl chloride, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC), dansyl chloride (DNS-Cl) [21] and o-phthaldialdehyde (OPA) [16] have been employed. An interesting alternative to these detection approaches is mass spectrometry (MS) that presents higher sensitivity and selectivity than other systems [5] and provides structural information being not necessary a derivatization step although sometimes it is also employed.…”