High-pressure liquid chromatography fractions

Kamens, R., D. Bell, A. Dietrich, J. Perry, R. Goodman, L. Claxton, and S. Tejada, Mutagenic Transformation of Dilute Wood Smoke Systems in the Presence of Ozone and Nitrogen Dioxide. Analysis of Selected High-Pressure Liquid Chromatography Fractions from Wood Smoke Particle Extracts, Environ. Sci. Technol., 19, 63-69 (1985). 

XAD resins have been used to collect and concentrate organic materials from seawater. They can also be used as packings for fractionation by column chromatography. While they have been used in simple gravity flow column chromatography, high pressure liquid chromatography has also been used [74-78]. 

Isotope fractionation between the vapor phase and the dissolved aqueous phase has been studied only for toluene and trichloroethylene (carbon only [545, 690]). Fractionation associated with adsorption has been quantified only for toluene in regard to sample extraction using a poly(dimethylsilo-xane)-coated solid-phase microextraction fiber [373] and qualified for benzene, toluene, and ethylbenzene based on high-pressure liquid chromatography analyses of isotopically labeled and unlabeled compounds (carbon and hydrogen [692]). Isotope fractionation associated with the reductive dechlorination of chlorinated ethylenes by zero-valent iron and zinc has been... 

The application of atomic spectroscopic instruments as element-specific detectors in chromatography has been reviewed by van Loon More recently, Krull has extensively reviewed their use in high pressure liquid chromatography (HPLC). Atomic spectrometry has found wide acceptance in the field of liquid chromatography because, in most cases, the fractions can be directly analysed after elution from the column. However, it is possible to use the technique for the analysis of solid samples without first dissolving the matrix. This is particularly useful after electrophoresis, where the fractions are fixed either in a gel or on paper. Kamel et al. have shown that it is possible to cut the appropriate sections and insert them into the carbon furnace for analysis. The disadvantage of this approach is that the precision is usually poorer (about 10%) and it is difficult to calibrate the instrument. Nevertheless, this approach is very useful if it is used for qualitative speciation. 

Tar. Before the development of gas chromatography (gc) and high pressure liquid chromatography (hplc), the quantitative analyses of tar distillate oils involved tedious high efficiency fractionation and refractionation, followed by identification or estimation of individual components by ir or uv spectroscopy. In the 1990s, the main components of the distillate fractions of coal tars are determined by gc and hplc (54). The analytical procedures included in the specifications for tar bulk products are given in the relevant Standardization of Tar Products Tests Committee (STPTC) (33), ISO (55), and ASTM (35) standards. 

An example is the amount-of-substance fraction of glycated haemoglobin Ale in total haemoglobin measured by high-pressure liquid chromatography-mass spectrometry [8] and a related BCR certified reference material 405 [9],... 

A portion (30.5 g) of the residue collected above was subjected to fractional distillation under reduced pressure (0.1-0.15 mm/Hg). The temperature was slowly raised to 125°C and the materials collected were kept separate. The temperature was then raised between 140°-160°C where the major fraction was collected (14 g). GC analysis showed >96% THC. Further purification on a silica gel column gives THC with at least 98% purity. An improvement of this process includes the use of high pressure liquid chromatography (HPLC). The preparation of dronabinol and related compounds have employed acid-catalyzed electrophilic condensation of a 5-alkylresorcinol such as 5-n-pentylresorcinol (commonly known as olivetol) and a menthadienol, followed by cyclization yield of desired product is about 17-22% (Petrzilka et al., Helv. Chim. Acta, 52, 1102 (1969)). 

Reverse phase high pressure liquid chromatography (HPLC) was used to further fractionate the sample and add another dimension of specificity (8,21). The extract was evaported to dryness and taken up in CHCI3. The entire extract was injected onto a DuPont Zorbax ODS column at 40°C using 2 cc/min. CH3OH mobile phase. Typical chromatograms are shown in Figure 2. 

Although it is possible to estimate apoC concentrations in lipoprotein fractions by delipidation, electrophoresis or isoelectric focusing, staining, and densitometry [e.g., (C5, N3)], or by high-pressure liquid chromatography (H6), most reported measurements of plasma apoC concentration have been by immunological means. These include radioimmunoassay (K8, K9, S17), electroimmunoassay (A4, A5, C27), radial immunodiffusion (P21), and enzyme immunoassay (H29). 

Factors that inhibit the CA, called allatostatins (H), have been extracted from the brain as well as the CC and CA of adults (12) and from the brains of larvae (13. 14). Since one adult brain equivalent elicited about the same inhibition of JH synthesis in vitro as 10-20 pairs of CA (12. 15). brain tissue was used as a source of material for the identification of allatostatins (14). Following initial purification of active material on a reverse phase (RP) Cj cartridge, high pressure liquid chromatography (HPLC) was used to separate the active material into several fractions. Two of these fractions were further purified and four similar amidated peptides, allatostatins 1-4, have been isolated and sequenced (Fig. 1). Synthetic peptides have the same retention times as the native materials on HPLC. The order of activity of the allatostatins is l>2-4>3. The action of these peptides on the CA In vitro is reversible. Allatostatin 1 also inhibits CA of adult PerlDlaneta amerlcana Qi). 

Before the development of gas chromatography and high-pressure liquid chromatography, the presence of peanut oil (as an olive oil adulterant) could be detected because peanut oil contains about 5% arachidic acid. Arachidic acid is insoluble in cold alcohol unlike stearic and palmitic acids (110). Methods for the detection of arachidic acid include the Bellier, Evers, Evers-Bellier, and Renard tests (110, 121). Arachidic acid is predominant in the lecithin and cephalic fractions of peanut oil (122). Detection methods for toxic oils as an adulterant in edible oils such as peanut oil have been reviewed (123, 124). 

Although there are obvious differences in the concentrations of the organic vanadium complexes found in the shallow and deep drill cores, the nature of the vanadium complexes present appeared to be virtually identical, as shown by high pressure liquid chromatography (C18 column, methanol solvent at 3 cc/min) of the vanadium porphyrin fractions extracted from core samples taken at depths of 90-92 m and 29-31 m. It would clearly be desirable to extend such studies to samples taken from much greater depths in the Toolebuc formation. 

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