Column In Conjunction Research Articles

Use of Small Charcoal/Alumina Cleanup Columns in Determination of Trichothecene Mycotoxins in Foods and Feeds

Small charcoal/alumina cleanup columns have been effectively used to remove interfering materials from grain, feed, and food extracts prior to chromatographic determination of trichothecene mycotoxins. A thin layer chromatographic method has been developed that can simultaneously detect part per billion concentrations of deoxynivalenol, fusarenon X, nivalenol, T-2 toxin, HT-2 toxin, neosolaniol, and diacetoxyscirpenol in food and feed samples. Recoveries of 90-99% can be obtained. The use of charcoal/alumina cleanup columns in conjunction with liquid chromatography and gas chromatography of trichothecenes is also discussed.

Comparison of Institutional and Commercial Anion-Exchange Materials in Trial of Anticoagulant Monitoring

The use of small institutionally prepared heparin removal (HR) columns in conjunction with the prothrombin time (PT) and activated partial thromboplastin time (aPTT) has been suggested as an alternative to dilutional prothrombin times (DPT) of the Owren type for monitoring coumarin influence in the presence of heparin. The commercially available product Heparsorb® (TEAE cellulose) was studied in a parallel trial with me proven ECTEOLA microcolumns used in the initial descriptions of the PT/HR and aPTT/HR. The Heparsorb procedure was modified to eliminate the second centrifugation step by placing the tablet on a column support. This was the only departure from manufacturer's specifications. The TEAE cellulose tablet was found to be as effective as the ECTEOLA microcolumn in removing 10 units/mL of heparin from normal and coumarin-treated patient plasmas. The commercial product had the advantage of not requiring refrigeration. The accuracy of the Heparsorb procedure for routine anticoagulant monitoring is now being evaluated.

The use of microparticulate guard columns in reverse-phase high-performance liquid chromatography

The use of mciroparticulate guard columns in conjunction with high efficiency reverse-phase columns has been evaluated in terms of system efficiency and peak symmetry using three standard test mixtures. The effects of linking tube dimensions, particle size of guard column packing and the use of low or zero dead volume couplings have been investigated. Both valve and stopped-flow injection techniques have been used. Recommendations are given for the most efficient use of guard columns.

Determination of Free Fatty Acids in Natural Oils and Alkyd Resins by High Performance Liquid Chromatography

Abstract Mixtures of free fatty acids in natural oil and alkyd resin samples have been analyzed using a μBondapak Free Fatty Acid column in conjunction with a ternary mobile phase. Variation of the mobile phase composition allows ‘‘fingerprinting'’ as well as quantitation of the fatty acid components. Samples can be analyzed in ten minutes by this method. The results of the application of this technique to the identification of oil sources of fatty acids as well as the production of fatty acids during alkyd resin synthesis are given. Good agreement is observed for fatty acid compositions determined via HPLC with those obtained by gas chromatographic methyl ester analysis.

Reverse Phase High Performance Liquid Chromotography of the 2′- and 3′-Nucleotide Monophosphates

Abstract A radial compression reverse phase column In conjunction with a high performance liquid chromotographic system has been developed for the separation of nucleotides, with special emphasis on the separation of the 2′- and 3′-nucleotide monophosphates which are produced by the base hydrolysis of RNA. The complete separation of the eight 2′- and 3′-isomers (as well as cyclic AMP) can be accomplished in twenty-five minutes using radial compression chemical bonded alkyl (C-18) reverse phase column by eluting with a reverse ionic strength gradient. Previous separation of these 2′- and 3′- isoraers required considerably longer time using the ion-exchange high performance liquid chro-matography methods.

Isolation of P700-chlorophyll-protein complex from a blue-green alga by a nondetergent method

A procedure has been developed for the isolation of a P700-chlorophyll-protein complex from a blue-green alga by a nondetergent method. The use of a Sepharose 4B column in conjunction with sucrose density-gradient centrifugation allows the separation of this complex from three other chlorophyll a-containing fractions which have higher ratios of carotenoids to chlorophyll a. Isoelectric focusing results in a single band with an isoelectric point at 4.5. Analysis of the major (green) fraction reveals the presence of P700. The absorption and emission spectra of this complex are reported.

Separative determination of ascorbic acid and erythorbic acid in animal tissues by high-performance liquid chromatography.

A method for the separation and determination of ascorbic acid (AsA) and erythorbic acid (ErA) in animal tissues is described. It employs high-performance liquid chromatography on a LiChrosorb-NH2 column in conjunction with a mixture of acetonitrile, acetic acid and water as an eluant. Application of the method, which is sensitive, rapid and simple, to the analyses of AsA and ErA in animal tissues such as liver, adrenals, spleen, kidneys and heart gave satisfactory results. Dehydro-AsA and dehydro-ErA in rat liver could be determined after reduction with H2S. The method was shown to be useful for the routine analyses.

Steroid analysis by gas chromatography with SCOT and wide‐bore WCOT columns

AbstractGlass capillary columns are ideal for analysis of urinary steroid profiles (i.e. the total steroid neutral fraction without prior separation into sub‐groups).In this paper performance of both SCOT and wide‐bore WCOT columns has been compared, resulting in no significant quantitative difference on urine extracts run as trimethylsilyl ether derivatives. However, because of increased efficiency the WB‐WCOT column exhibited more sensitivity in measurement of small amounts of 11‐ox‐aetiocholanolone. Sensitivity of other steroids was greatly enhanced by use of either SCOT or WB‐WCOT, leading to an almost tenfold increase over conventional packed columns (e.g. androsterone and aetiocholanolone < 40 μg per 24 h urine sample). A simple splitless injection system (based on a design of Dr. W. Greenaway, Oxford University) is presented.Experiments were also carried out using a SCOT column in conjunction with an FM‐electron capture detector. Whilst efficiency was impaired due to the design of the detector, use of He (carrier) and N2 (make up gas) showed that several steroid derivatives could be easily measured at well below the 10−10 g level with much more rapid retention times than with a 1½m packed column. Highly successful separation of 19 amino acids (as fluoro‐acyl derivatives) was achieved in 35 minutes using a SCOT (30 m) SP2100 column.

Estimation of citral in lemon oil by gas–liquid chromatography using a capillary column

AbstractA rapid quantitative method for the estimation of citral in lemon oil is described. It uses temperture‐programmed gas‐liquid chromatography on an OV 101 capillary column in conjunction with methyl n‐decanoate as the internal standard. A calibrtion graph is employed to convert the sum of the α‐citral and β‐citral peak areas, relative to that of the internal standard, into citral content. Analysis of six commercial lemon oil samples is recorded, the results being expressed as perecentage citral content (g 100 ml−1) together with an indication of the relative abundance of the two isomers. The method is shown to be both accurate and reproducible.

Purification of catechol-O-methyltransferase by affinity chromatography

Summary An affinity chromatographic system has been developed to purify catechol-O-methyltransferase. This system consists of a 3,4-dimethoxy-5-hydroxyphenylthylamine-agarose conjugate in which the ligand is coupled through a 30-A hydrocarbon side chain. Partial purification of the enzyme (approx. 40 fold) can be achieved by passing the 100,000 × G supernatant obtained from homogenized rat liver through a column containing this conjugate and eluting with buffers of increasing ionic strength. Further purification of the enzyme (approx. 900 fold) has been achieved by using this affinity column in conjunction with several of the more classical enzyme purification techniques.

The purification of porcine heart lactate dehydrogenase by affinity chromatography

The large scale purification of the heart (H 4 isoenzyme of porcine lactate dehydrogenase (EC 1.1.1.27) is described, utilizing an oxamate inhibitor affinity column in conjunction with conventional ion-exchange chromatography. The isoenzyme is obtained in relatively good ( > 60%) yield, and shows one band on electrophoresis.

A Photometric Determination of Vitamin D in Presence of Vitamin A

A procedure suitable for the relatively rapid photometric determination of vitamin D in presence of vitamin A in simple mixtures, such as dry vitamin A and D powders and some multivitamin preparations, is presented as a “Basic Method,” using chro-matography on Florex XXS. Modifications of the method to provide applications of the procedure to numerous polyvitamin products also are described. The great diversity of formulations of such preparations may necessitate the use of various techniques for the removal of interfering substances. Several of these techniques, such as preliminary extraction with petroleum ether or the use of an alumina or poly-ethylene powder chromatographic column in conjunction with the “Basic Method,” are provided. The advantages and limitations of the different modifications are discussed. A comparison of results with those obtained by the U. S. P. bioassay procedure (Table I) shows the accuracy and precision obtainable.

Chromatography of deoxyribonucleic acids on calcium phosphate columns

Calf thymus DNA in 0.005 M phosphate buffer (pH 6.7) was subjected to Chromatographic analysis on calcium phosphate columns in conjunction with linear gradient elution with phosphate solution ranging from 0.005 to 0.4 M at constant pH. Eluant fractions (3–5 ml.) were collected hourly for 120 hr. The course of elution of DNA was followed by measuring the absorbance of each fraction at 260 mμ. It was found that DNA initially adsorbed on the column was not eluted until the phosphate concentration of the eluting solution approached 0.15 M. Up to 72% of total ultraviolet-absorbing material was eluted in the range between 0.15 and 0.25 M phosphate. No additional elution peaks appeared between 0.25 and 0.40 M phosphate. The column was evaluated with regard to its capacity to differentiate DNA from the products obtained by short-term (30-min.) digestion of DNA by DNAse. Chromatographic analyses of mixtures of untreated DNA with such DNA digests revealed at least three major fractions as indicated by distinct elution peaks. The first fraction was not adsorbed by the column and came through immediately in 0.005 M phosphate. A second peak appeared at 0.045 M phosphate; a third elution maximum occurred at 0.2 M phosphate. The latter peak corresponded to that obtained with untreated DNA when chromatographed alone. The present results imply that high-molecular-weight deoxypoly-nucleotides can be separated from undegraded DNA, under mild conditions of pH and ionic strength, by calcium phosphate column chromatography.