Analysis of anthocyanins in commercial fruit juices by using nano‐liquid chromatography‐electrospray‐mass spectrometry and high‐performance liquid chromatography with UV‐vis detector

Abstract

Nano-LC and conventional HPLC techniques were applied for the analysis of anthocyanins present in commercial fruit juices using a capillary column of 100 μm id and a 2.1 mm id narrow-bore C(18) column. Analytes were detected by UV-Vis at 518 nm and ESI-ion trap MS with HPLC and nano-LC, respectively. Commercial blueberry juice (14 anthocyanins detected) was used to optimize chromatographic separation of analytes and other analysis parameters. Qualitative identification of anthocyanins was performed by comparing the recorded mass spectral data with those of published papers. The use of the same mobile phase composition in both techniques revealed that the miniaturized method exhibited shorter analysis time and higher sensitivity than narrow-bore chromatography. Good intra-day and day-to-day precision of retention time was obtained in both methods with values of RSD less than 3.4 and 0.8% for nano-LC and HPLC, respectively. Quantitative analysis was performed by external standard curve calibration of cyanidin-3-O-glucoside standard. Calibration curves were linear in the concentration ranges studied, 0.1-50 and 6-50 μg/mL for HPLC-UV/Vis and nano-LC-MS, respectively. LOD and LOQ values were good for both methods. In addition to commercial blueberry juice, qualitative and quantitative analysis of other juices (e.g. raspberry, sweet cherry and pomegranate) was performed. The optimized nano-LC-MS method allowed an easy and selective identification and quantification of anthocyanins in commercial fruit juices; it offered good results, shorter analysis time and reduced mobile phase volume with respect to narrow-bore HPLC.

LC–MS/MS and UPLC–UV Evaluation of Anthocyanins and Anthocyanidins during Rabbiteye Blueberry Juice Processing

“…The lesser anthocyanins may consist of acetoly, malonoyl and coumaroyl compounds [10]. In this study, 5 coumaroly-glucosides and 5 acetyl-pyranoside anthocyanins were searched for and three minor coumaroyl anthocyanin compounds were identified using MS/MS ions, as confirmed in literature (Table 1) [30,41,43]. The compounds were delphinidin-3-(p-coumaroyl-glucoside), cyanidin-3-(p-coumaroyl-glucoside), and petunidin-3-(p-coumaroyl-glucoside) which, to the best of our knowledge, have not been reported in RAB blueberries (Figure 2).…”

“…A contributing factor is the difference in calculating total anthocyanidins by summation of individual anthocyanidin amounts compared to using the pH differential method which calculates total anthocyanidins as one group of compounds based on UV spectra [59,60]. In general, blueberry results reported from a spectrophotometric method are higher in the same sample than results from methods quantifying the individual anthocyanidins [19,30,61]. Yet, the reverse situation has also been reported [62].…”

Theory and Practice of UHPLC and UHPLC–MS

“…Recent research trends have identified some food polyphenols as potential agents of health promotion for their ability to act as antioxidants and free-radical scavengers. A great percentage of articles deals with the analysis of this class of molecules in different food matrices such as fruit juices (Fanali et al, 2011b; …”

“…The analysis of anthocyanins in commercial red fruit juices was assessed by nano-LC by Fanali et al (2011b). Although strong acid conditions (5%, v/v HFo) were used, the 100 mm I.D.…”

Juice Analysis in Citrus: Latest Developments

“…In fact, the use of chromatographic columns with smaller I.D., e.g., from 4.6 mm (classical column) to 100 m m (capillary column) may result in up to 2,000-fold increase in both sensitivity and resolution. This feature, together with the low costs owing to the use of considerably smaller amounts of chiral stationary phase, along with the limited eluent volumes, makes nano-LC a viable alternative to classical ones such as HPLC for the analysis of citrus juice (Fanali et al 2011 ;D'Orazio et al 2007 ) . However, to date, very few papers have been published on the enantioselective separation, identi fi cation, and quanti fi cation carried out by nano-liquid chromatography.…”