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Ionic liquid-based cloud-point extraction of quercetin for its sensitive HPLC–UV determination in juice samples

Rasoolzadeh F., Hashemi P., Nazari S. F

Acta Chromatographica

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2017

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Vol. 29, no. 4

493--496

EN

An ionic liquid-based cloud-point extraction (IL-CPE) method was developed for the extraction of quercetin in juice samples before its determination by high-performance liquid chromatography (HPLC). 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) was used as the ionic liquid. The cloud-point extraction parameters such as sample pH, extraction temperature, extraction time, amount of ionic liquid, extraction volume, and salt concentration were carefully studied and optimized for the achievement of maximum extraction recovery. Under the optimized conditions, i.e., 20 min heating at 40 °C, 100 μL IL volume, pH 2.0, and no salt addition, a mean recovery of 92.5% and an enrichment factor of 20 were obtained for quercetin. Relative standard deviation of the method was 3.76% for 6 replicates, and the calculated detection limit (3σ) of quercetin was 0.002 mg L−1. The method, coupled to HPLC was successfully applied to the sensitive determination of quercetin in apple and gapes juice samples with quantitative recoveries.

2

Comparison of headspace solvent microextraction, hydrodistillation solvent microextraction, and solid-phase microextraction for the study of volatile components of Kelussia odoratissima Mozaff. by GC-MS

Hashemi P., Yarahmadi A, Shamizadeh M, Khademi K

Acta Chromatographica

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2012

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Vol. 24, no. 1

97--109

EN

Kelussia odoratissima Mozaff. is a wild and endangered endemic plant found only in limited areas of central Zagros mountains, Iran. Three microextraction methods, that is, headspace solvent microextraction (HS-SME), hydrodistillation solvent microextraction (HD-SME), and solid-phase microextraction (SPME), and a conventional hydrodistillation method were used and compared for the extraction and gas chromatography- mass spectrometric (GC-MS) analysis of volatile components of the plant. In the HS-SME and HD-SME methods, a suspended n-heptadecane microdroplet was used for the extraction from the sample headspace, while in the SPME method, a PDMS fiber was applied. The highest extraction efficiency was obtained for the SPME method, with the highest number of identified components and best precision. As a consequence, the SPME method was used for the comparison of the volatile components of seeds, leaves, and pedicles of K. odoratissima collected from three different regions. One of the major components of the plant was butyl phthalide. The levels of this compound in the extractions from leaves, pedicles, and seeds were 34.1, 23.8, and 12.9%, respectively. The results also showed considerable variation between the volatile components of the samples collected from different areas.

3

A study of the effects of cultivation variety, collection time, and climate on the amount of oleuropein in olive leaves

Hashemi P., Delfan B, Ghiasvand A. R., Alborzi M, Raeisi F

Acta Chromatographica

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2010

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Vol. 22, no. 1

133--140

EN

Effects of cultivation variety, collection time, and climate on amounts of oleuropein (OE), a strong antioxidant, in olive leaves were studied. A modified ultrasound-assisted method was used for efficient and quantitative extraction of OE from olive leaf samples before their analysis by a rapid HPLC method. Under the optimized conditions, the extraction was performed in two successive steps with an RSD better than 2.95% ( n = 5) and a detection limit of 0.02 μg OE. The amount of OE was determined in twelve samples of olive leaves from Mary Zeitoon, Koroneiki , and Sevillana varieties cultivated in three different regions of Iran after collection in two different seasons. The results confirmed that the amounts of OE varied in different olive varieties with mean values of 127, 115, and 144 μg g -1, respectively, although statistical tests indicated a significant interaction of collection time and climate with olive variety. In general, the OE concentration was significantly higher in the cold season and in the tropical regions than in the hot season and the temperate region.

4

Headspace-solvent microextraction for identification of volatile components of Myrtus communis L.

Hashemi P., Abolghasemi M. M., Ahmadi S., Ghiasvant A. R.

Acta Chromatographica

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2009

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Vol. 21, no. 1

139-149

EN

Headspace-solvent microextraction (HS-SME) and hydrodistillation coupled with GC-MS have been used for isolation and identification of the volatile components that characterize Myrtus communis L. aroma. In the HS-SME method a suspended micro-drop of n -butanol was used as solvent. The effect of six different parameters on extraction efficiency, including sample weight, drop volume, extraction temperature, conditioning time, extraction time, and ionic strength were optimized using a simplex optimization method. The volatile components were studied both by HS-SME and an ordinary hydrodistillation method and the major components identified were 1,8-cineol, #945-pinene, limonene, and linalool.

5

Kinetic spectrophotometric determination of ascorbic acid in pharmaceutical formulations

Fathi M. R., Elahi R., Hashemi P.

Chemia Analityczna

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2005

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Vol. 50, No. 6

1069-1076

EN

Sensitive, simple and fast kinetic spectrophotometrii; method for determination of ascorbic acid has been described. The procedure is based on reduction of iron(IIi) to iron(II) by ascorbic acid and formation of a complex between iron(II) and 2.2'-bipyridine. Reaction rate was monitored spectrophotometrically by measuring the increase in absorbance of the formed complex al 522 nm. Ascorbic acid was determined using a fixed-time (3 min} method in two concentration ranges: 0.1-15 mg mL-1 and 20-45 mg ml.-1: the corresponding correlation coefficients were 0.998 and 0.999, respectively. Relative standard deviation for 10 replicate determinations of ascorbic acid in 2 mg mL-1 solution was 0.47% and detection limit equalled 0.032 μg mL-1. The proposed method was successfully applied to the determination of ascorbic acid in pharmaceutical formulations. Reliability of determination was confirmed applying standard iodimetric method.

PL

Opisano czułą, prosta i szybką metodę oznaczania kwasu askorbowego. Procedura polega na redukcji żelaza(ITI) do żelaza(II) za pomocą kwasu askorbowego i tworzeniu kompleksu żelaza(II) z 2.2'-dipirydyną. Szybkość reakcji mierzono na podstawie wzrostu absorbancji przy 522 nm. Kwas askorbowy oznaczano metodą stałego czasu (3 min) w zakresie stężeń 0,1-15 mgL-1 i 20-45 mgmL-1.Względne odchylenie standardowe, obliczone na postawie 10 pomiarów kwasu askorbowego o stężeniu 2 mg mL-1, wynosiło 047%. a granica wykrywalności - 0,032 μg mL-1. Wiarygodność oznaczeń potwierdzono metodą jodometryczną.