Rapid‐resolution liquid chromatography/mass spectrometry for determination and quantitation of polyphenols in grape berries

Abstract

A rapid-resolution liquid chromatography/mass spectrometric (RRLC/MS) method for detection and quantitation of polyphenols in grape berry skins and seeds has been developed. Pulp-free berry skins were treated with liquid nitrogen and ground; seeds were also ground. Then, 3 g of samples were extracted with 30 mL of a mixture of methanol/water/formic acid 70:30:1 (v/v/v) under sonication and 1 microL of the final extract was injected into two 100 x 2.1 mm i.d., 1.8 microm Zorbax Eclipse plus C18 columns connected in series. Compounds were fractionated using a gradient elution of acidified acetonitrile/methanol 50:50 (v/v)/water. Columns were thermostatted at 70 degrees C. MS was carried out on an Agilent 6410 QqQ instrument equipped with an electrospray ionization source. Positive and negative MS/MS product ion scans were used for compound identification, whereas positive full scan MS in the m/z range 200-1400 was used for quantitation. By means of mass spectra comparison, various flavonols, flavan-3-ols, anthocyanins and stilbenes were identified. Quantitation was performed by external calibration, and concentration values were corrected for matrix effect that was evaluated in separate experiments. Semi-quantitative estimation was performed for compounds for which standards were not commercially available. Recoveries ranged from 90-102% with relative standard deviation (RSD) <5%, whereas the between samples RSD was in the range 4-12%. Two surrogate standards were used for quality control. The developed method was applied to analyze the polyphenol content of three Vitis vinifera table cultivars at physiological maturity and after proper preservation for 6 weeks. Results demonstrated that during preservation about half of the polyphenol content was lost.

Novel aspects of grape berry ripening and post-harvest withering revealed by untargeted LC-ESI-MS metabolomics analysis

“…We investigated the impact of the matrix effect on our analysis as described by Cavaliere et al (2008) and found that most of the curves (representing 80% of the identified metabolites) reached a plateau at higher dilutions, allowing us to calculate a correction factor. It was not possible to obtain a reliable correction factor for the other compounds, but most of this group comprised low-abundance metabolites.…”

“…The matrix effect for all putatively identified compounds was evaluated as described by Cavaliere et al (2008). Sample extracts were diluted with the extraction solvent (undiluted, 1:2, 1:5, 1:10, 1:25 and 1:50) and 10 ll of each dilution were analyzed in duplicate by HPLC-MS.…”

“…Most studies in the latter category have focused on one or a small group of related compounds, such as anthocyanins (Wang et al 2003), procyanidins (Wu et al 2005), or anthocyanins and flavonols (Mattivi et al 2006;Downey and Rochfort 2008). A small number of more comprehensive studies have been reported, including one encompassing anthocyanins, flavonols and hydroxycinnamic acids (Guerrero et al 2009) and another covering anthocyanins, procyanidins, flavonols and stilbenes (Cavaliere et al 2008). The latter is probably the broadest investigation carried out thus far, involving the simultaneous detection of 40 different compounds in the berry skins of three table cultivars.…”

Antiherpetic activity of a flavonoid fraction from Ocotea notata leaves

“…They were directly identified in the flavonoid fraction by HPLC co-injection with standards and through the negative ions observed in the direct infusion ESI-MS of the flavonoid fraction. Quasimolecular ions at m/z 289 (compounds 1 and 2) and m/z 477 (compound 6; MS/MS 477, 301) were observed in the negative ESI mass spectra of the flavonoid fraction (Charrouf et al, 2007;Cavaliere et al, 2008). (Foo et al, 2000;Zhang et al, 2003;He et al, 2007, Li & Deinzer, 2007.…”

Methods for the Evaluation of Polyphenolic Content in “Uva Di Troia Canosina” Grape and Seeds at the Different Maceration Stages

“…Their concentration and composition in grapes depends on the cultivar and so it is influenced by viticultural and environmental factors, such as climate conditions, maturity stage, and production area [3][4][5][6]. Polyphenols exhibit beneficial effects on human health thanks to the strong free radical scavenging and antioxidant activity, as well as cardioprotective, vasodilatatory, anticarcinogenic, anti-inflammatory, antiallergic, antibacterial, immune-stimulating, antiviral, and 2 ISRN Analytical Chemistry estrogenic properties [7][8][9].…”