High performance liquid extracts

Analytical Supercritical Fluid Extraction and Chromatography Supercritical fluids, especially CO9, are used widely to extrac t a wide variety of solid and hquid matrices to obtain samples for analysis. Benefits compared with conventional Soxhlet extraction include minimization of solvent waste, faster extraction, tunabihty of solvent strength, and simple solvent removal with minimal solvent contamination in the sample. Compared with high-performance liquid chromatography, the number of theoretical stages is higher in... 

C. L. Hsu and R. R. Walters, Assay of the enantiomers of ibutilide and artilide using solid-phase extraction, derivatization and achhal-cliiral column-switcliing high-performance liquid cliromatography , J. Chromatogr. B 667 115-128 (1995). 

Acetonitrile and hydrogen cyanide are hy-products that may he recovered for sale. Acetonitrile (CH3CN) is a high polarity aprotic solvent used in DNA synthesizers, high performance liquid chromatography (HPLC), and electrochemistry. It is an important solvent for extracting butadiene from C4 streams. Table 8-1 shows the specifications of acrylonitrile, HCN, and acetonitrile. ... 

Multi-element analyses involving solvent extraction and high performance liquid chromatography (HPLC) have also been described. The extracts, containing metal-chelate complexes with sulphur-containing reagents, such as dithizone and diethyldithiocarbamate, were used directly for determination of the metals by HPLC.14... 

ECD = electron capture detector GC = gas chromatography HPLC = high-performance liquid chromatography MC = microcoulometric detector MS = mass spectrometry NICI = negative ion chemical ionization RSD = relative standard deviation SPE = solid phase extraction... 

Demeter J, Heyndrickx A. 1979. Selection of a high-performance liquid chromatographic cleanup procedure for the determination of organochlorine pesticides in fatty biological extracts. Vet Hum Toxicol 21 151-155. 

KAYALI-SAYADI M N, RUBIO-BARROSO S, CUESTA-JIMENEZ M P and PALO-DIEZ L M (1998) Rapid determination of polycyclic aromatic hydrocarbons in tea infusion samples by high-performance liquid chromatography and fluorimetric detection based on solid-phase extraction , 123, 2145-8. 

CALDWELL c R (2001) Oxygen radical absorbance capacity of the phenolic compounds in plant extracts fractionated by high-performance liquid chromatography, ,4Biochem, 293, 232-8. 

High performance liquid chromatography (HPLC) has been by far the most important method for separating chlorophylls. Open column chromatography and thin layer chromatography are still used for clean-up procedures to isolate and separate carotenoids and other lipids from chlorophylls and for preparative applications, but both are losing importance for analytical purposes due to their low resolution and have been replaced by more effective techniques like solid phase, supercritical fluid extraction and counter current chromatography. The whole analysis should be as brief as possible, since each additional step is a potential source of epimers and allomers. 

Although saponification was found to be unnecessary for the separation and quantification of carotenoids from leafy vegetables by high performance liquid chromatography (HPLC) or open column chromatography (OCC), saponification is usually employed to clean the extract when subsequent purification steps are required such as for nuclear magnetic resonance (NMR) spectroscopy and production of standards from natural sources. 

Kamikura, M. and Nakazato, K., Natural yellow colours from gardenia fruit and colours found in commercial gardenia extract analysis of natural yellow colours by high performance liquid chromatography, J. Food Hygiene Soc. Japan, 26, 150,1984. 

Saito, K., A new enzymatic method for extraction of precarthamin from dyer s saffron (Carthamus tinctorius) florets, Z. Lebensmitt. Untersuch. Forsch., 197, 34, 1993. Cserhati, T. et ah. Separation and quantitation of colour pigments of chili powder (Capsicum frutescens) by high-performance liquid chromatography-diode array detection, J. Chromatogr. A, 896, 69, 2000. 

Wouters, J., High performance liquid chromatography of anthraquinones analysis of plant and insect extracts and dyed textiles. Stud. Conserv., 30, 119, 1985. 

Lin C-H, RH Lerch, EM Thurmkan, HE Garrett, ME George (2002) Determination of isoxaflutole (Balance) and its metabolites in water using solid-phase extraction followed by high-performance liquid chromatography with ultraviolet or mass spectrometry. J Agric Eood Chem 50 5816-5824. 

Cherchi, A., Spanedda, L., Tuberoso, C., and Cabras, P. (1994). Solid phase extraction and high-performance liquid chromatographic determination of organic acids in honey. 

High-performance liquid chromatography (HPLC) with a micellar mobile phase or with a selective pre-column or reaction detection system has also been used to determine alkylenebis(dithiocarbamaes). ° Zineb and mancozeb residues in feed were determined by ion-pair HPLC with ultraviolet (UV) detection at 272 nm. These compounds were converted to water-soluble sodium salts with ethylenediaminetetra-acetic acid (EDTA) and sodium hydroxide. The extracts were ion-pair methylated with tetrabuthylammonium hydrogensulfate (ion-pair reagent) in a chloroform-hexane solvent mixture at pH 6.5-8.S. The use of an electrochemical detector has also been reported. ... 

Residue analytical methods for neonicotinoids in crops, soil and water samples have been developed. The basic principle of these methods consists of the following steps extraction of the crop and/or soil samples with acetone or the other organic solvent, cleanup by liquid-liquid partition or column chromatography, and quantitative analysis by high-performance liquid chromatography with ultraviolet detection (HPLC/UV). Simple column cleanup procedures are used to improve the accuracy and sensitivity of these methods. 

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