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Chromatography Division, South San Francisco, Calif., for technical assistance on fluorescence detector wavelength scans; and Linda Rouse, associate chemist, McCormick and Co., Hunt Valley, Md., for high-performance liquid chromatography–mass spectrometry

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objective of our study was to identify and characterize the anthocyanins in herbaceous peony species from different regions of the world using reverse-phase high-performance liquid chromatography (HPLC) with diode array detection in tandem with electrospray

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Direct spectrophotometric determination of quercetin content in onions (Allium cepa L.) was investigated as a possible alternative to high-performance liquid chromatography (HPLC) analysis. Quercetin content in five onion varieties was monitored at 362 nm and quantified using simple spectrophotometric and HPLC methods. HPLC revealed that 3,4'-Qdg and 4'-Qmg comprised up to 93% of total flavonol content detected in the studied varieties. These major quercetin conjugates combined (3,4'-Qdg + 4'-Qmg) and total flavonol conjugates quantified by HPLC correlated closely with spectrophotometer values. Correlation coefficients were 0.96 (P < 0.0001) for 3,4'-Qdg + 4'-Qmg and 0.97 (P < 0.0001) for total flavonol conjugates in onion. Simple spectrophotometric procedure proved to be a valid, efficient, and cost-effective method for the quantification of total quercetin in onion. Chemical names used: quercetin-3,4'-O-diglucoside (3,4'-Qdg); quercetin-4'-O-glucoside (4'-Qmg).

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A rapid and sensitive high performance liquid chromatography method for quantifying simultaneously sucrose, fructose and glucose in fruits and vegetables is reported. Samples were extracted in 95% ethanol, homogenized and treated at 95C for 20 min. The supernatant was stored at -20C overnight and filtered through a G-25 Sephadex column. Aliquots were evaporated, redissolved in water, filtered, and injected. A Sorbex NH2 column operated at room temperature was used for separations. The sugars were detected at 192 nm. The retention times were 4.8, 5.9 and 10.3 min for fructose, glucose and sucrose, respectively. The method was applied to twenty-one fruit and vegetable species with different maturity stages. In addition, quality characteristics such as firmness, pH, acidity, soluble solids and color were evaluated. Main sugars for the different samples varied among species. In temperate fruits, fructose and glucose were the predominant sugars, while in tropical and subtropical fruits, the main sugar was sucrose. On the sampled vegetables, fructose was the primary sugar, although at very low levels. Quality characteristics coincided with sugar levels found among the different species.

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Abstract

Methods of chloroplast pigment extraction and sample preparation previously established for leaves do not apply for fruits and other organs of several horticultural crops. Methods presented in this report overcome these difficulties, and results presented show this procedure can be used for several diverse horticultural crops. A high performance liquid chromatography (HPLC) run time of 25 minutes in the isocratic mode gave baseline separation of chlorophyll a (chl a), chlorophyll b (chl b), and β-carotene while neoxanthin, violaxanthin, and lutein eluted as partially resolved peaks. A run time of 48 minutes in the linear gradient mode gives baseline separation of all 6 major chloroplast pigments.

Open Access

Abstract

A high performance liquid chromatography (HPLC) method was developed for analyzing vitamin B1, and the method was used with other HPLC methods to monitor vitamins C, B1, and B2 of fresh fruits and vegetables stored at different temperatures. Ascorbic acid content of most commodities either dropped after being placed in storage or decreased during storage. Thiamine increased during storage of ‘Tendergreen’ beans and decreased in ‘BelRus’ potatoes; whereas riboflavin decreased in ‘Tendergreen’ beans and increased in ‘Superior’ potatoes. The changes in other cultivars or commodities were not significant.

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Abstract

Ascorbic acid of fresh fruits and vegetables was extracted with 6% metaphosphoric acid and determined effectively by using a C18 cartridge in a radial compression module and 1.5% NH4H2PO4 mobile phase in a high performance liquid chromatograph.

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, a close relative of S. reginae ( Pirone et al., 2009 ). Bilirubin was previously known in the animal kingdom where it is produced as a breakdown product of heme. Preliminary high-performance liquid chromatography (HPLC) and ultraviolet

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cultivars. Fig. 1. Phenolic content (mg/100 g fresh weight, measured by high-performance liquid chromatography–photodiode array) of S. l. var. cerasiforme accessions. Values are the mean of three biological replicates; error bars = 1 se . Means sharing

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twice. Fractioning of the crude ethanolic SML extract by semipreparative high-performance liquid chromatography. Freeze-dried powder of ethanolic SML extract was dissolved in ultrapure water (50 mg mL −1 ) and divided in 15 fractions using a

Open Access