scholarly journals Gas Chromatographic Determination and Method Validation of Stigmasterol, Β-Sitosterol, Campesterol and Brassicasterol Contents of Turkish Cottonseed Oil Samples

2017 ◽  
Vol 5 (11) ◽  
pp. 1274 ◽  
Author(s):  
Cemile Özdemir Yücel ◽  
Hasan Ertaş ◽  
Fatma Nil Ertas
Keyword(s):  
Free Sterol ◽  
Solid Phase ◽  
Chromatographic Determination ◽  
Cottonseed Oil ◽  
Agricultural Products ◽  
Hydroxyl Groups ◽  
Flame Ionization ◽  
Extraction Step ◽  
Free Hydroxyl ◽  
Solid Phase Extraction Step

Plant sterols are important agricultural products for human health and consequently, for nutrition industries. In the present study, free sterol contents of crude Turkish cottonseed oil samples have been determined in a single analytical run by using a solid phase extraction step prior to the detection with a gas chromatography coupled with a flame ionization detector. Free hydroxyl groups of Stigmasterol, β-Sitosterol, Campesterol and Brassicasterol were derivatized by using N-methyl-N-trimethylsilyl trifluoroacetamide to enhance their volatility and, sterol content of the samples were, then, separated from their matrix by using a octadecylsilane cartridge. The eluates were injected into the gas chromatographic system and satisfactory recovery ratios were obtained. After having validated the method, it was applied into the analysis for cottonseed oil samples for their free sterol levels.

scholarly journals Simultaneous determination of 42 organic chemicals in bottled water by combining C18 extraction disk with GC-MS and LC/MS/MS technique

2009 ◽  
Vol 8 (1) ◽  
pp. 116-125 ◽  
Author(s):  
Bao-hui Jin ◽  
Feng Xiao ◽  
Bo Chen ◽  
Pei-jin Chen ◽  
Li-qi Xie
Keyword(s):  
Mass Spectrometry ◽  
Solid Phase ◽  
Bottled Water ◽  
Gas Chromatography Mass Spectrometry ◽  
Positive List ◽  
Extraction Step ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass ◽  
Solid Phase Extraction Step

A method for the determination of 42 hazard residues required by ‘Japan Positive List System’ in bottled water was described. Hazard compounds in bottled water were extracted with a solid phase extraction step using C18 disks. Determination was carried out by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography-tandem mass spectrometry (LC/MS/MS). The disk extraction has high throughput which is well adapted to isolate and enrich these compounds from large volumes of water. For the water sample spiked at three concentration levels (LOQ, 4 times LOQ and 8 times LOQ), the recoveries of all analytes ranged between 65% and 120% with a relative standard deviation < 24% (n=8).

On-chip electromembrane extraction followed by sensitive digital image-based colorimetry for determination of trace amounts of Cr(vi)

2020 ◽  
Vol 12 (4) ◽  
pp. 483-490 ◽  
Author(s):  
Fereshteh Zarghampour ◽  
Yadollah Yamini ◽  
Mahroo Baharfar ◽  
Ghazal Javadian ◽  
Mohammad Faraji
Keyword(s):  
Solid Phase Extraction ◽  
Water Samples ◽  
Solid Phase ◽  
Phase Extraction ◽  
Extraction Step ◽  
Electromembrane Extraction ◽  
On Chip ◽  
Extraction Preconcentration ◽  
Solid Phase Extraction Step

In this work, an on-chip electromembrane extraction coupled with the micro solid phase extraction step was developed for extraction, preconcentration, and determination of trace amounts of chromium(vi) in water samples.

Multiresidue Method for the Chromatographic Determination of Triazine Herbicides and Their Metabolites in Raw Agricultural Products

1995 ◽  
Vol 78 (3) ◽  
pp. 856-861 ◽  
Author(s):  
John R Pardue
Keyword(s):  
Solid Phase ◽  
Chromatographic Determination ◽  
Water Soluble ◽  
Agricultural Products ◽  
Triazine Herbicides ◽  
Average Recovery ◽  
Temperature Programmed ◽  
Nitrogen Phosphorus Detector ◽  
Nitrogen Phosphorus

Abstract A method is described for the determination of 19 triazine herbicides and 4 metabolites in 6 agricultural products that represent diverse matrixes. In addition, a modification of this method to determine the more water-soluble metabolite, de-sethyldesisopropylatrazine, is described. In both these procedures, residues are extracted with methanol, and the product coextractives are removed using solvent partition and cation-exchange solid-phase extraction chromatography. A nitrogen phosphorus detector and DB-17 megabore column are used for the temperature-programmed chromatographic determination of samples fortified at 0.02–1.0 ppm levels. Average recoveries ranged from 81.1 to 106.2% for the parent herbicides and from 59.6 to 87.5% for the metabolites on all crops. An average recovery of 101.1% was obtained for de-sethyldesisopropylatrazine.

scholarly journals Acid-mediated N-iodosuccinimide-based thioglycoside activation for the automated solution-phase synthesis of α-1,2-linked-rhamnopyranosides

2019 ◽  
Vol 91 (7) ◽  
pp. 1243-1255 ◽  
Author(s):  
Victoria R. Kohout ◽  
Alyssa L. Pirinelli ◽  
Nicola L. B. Pohl
Keyword(s):  
Solid Phase ◽  
Solution Phase ◽  
Phase Extraction ◽  
Phase Synthesis ◽  
Extraction Step ◽  
Solution Phase Synthesis ◽  
Single Coupling ◽  
Activation Conditions ◽  
Glycosylation Reaction ◽  
Solid Phase Extraction Step

Abstract Carbohydrate structures are often complex. Unfortunately, synthesis of the range of sugar combinations precludes the use of a single coupling protocol or set of reagents. Adapting known, reliable bench-chemistry reactions to work via automation will help forward the goal of synthesizing a broad range of glycans. Herein, the preparation of di- and tri-saccharides of alpha 1→2 rhamnan fragments is demonstrated using thioglycoside donors with the development for a solution-phase-based automation platform of commonly used activation conditions using N-iodosuccinimide (NIS) with trimethylsilyl triflate. Byproducts of the glycosylation reaction are shown to be compatible with hydrazine-based deprotection conditions, lending broader functionality to this method as only one fluorous-solid-phase extraction step per coupling/deprotection cycle is required.

The synthesis and structure of silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complexes

1986 ◽  
Vol 51 (7) ◽  
pp. 1430-1438 ◽  
Author(s):  
Alena Reissová ◽  
Zdeněk Bastl ◽  
Martin Čapka
Keyword(s):  
Free Surface ◽  
Hydroxyl Groups ◽  
Titanium Complex ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Cyclopentadienyl Anion

The title complexes have been obtained by functionalization of silica with cyclopentadienylsilanes of the type Rx(CH3)3 - xSi(CH2)nC5H5 (x = 1-3, n = 0, 1, 3), trimethylsilylation of free surface hydroxyl groups, transformation of the bonded cyclopentadienyl group to the cyclopentadienyl anion, followed by coordination of (h5-cyclopentadienyl)trichlorotitanium. The effects of single steps of the above immobilization on texture of the support, the number of free hydroxyl groups, the coverage of the surface by cyclopentadienyl groups and the degree of their utilization in anchoring the titanium complex have been investigated. ESCA study has shown that the above anchoring leads to formation of the silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complex.

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