摘要:

AbstractIn order to develop efficient separation methods for nucleotides according to their size and heterocyclic composition, the application of ion‐exchange, reverse‐phase, and normal‐phase adsorption HPLC has been studied. The comparative investigation of retention power and selectivity of various packings (non‐polar bonded‐phase and amino silicas) in relation to nucleotide length and composition yields data which enable suitable packings to be selected and a method of preparing the new packing for a particular separation problem to be formulated. Thus a new anion exchanger with high selectivity and dynamic mass transfer has been prepared for fractionation of large oligonucleotides. The effect of the eluent pH and composition (organic modifier, salt) on retention, selectivity, and resolution in ion‐exchange and reverse‐phase HPLC has been studied. The optimum separation conditions comprise elution with oppositely directed gradients of the salt and the modifier, use of a precolumn packing that provides the best protection for the main column without loss of its efficiency, and the optimum gradient program for the desired retention of the component of interest. The relation between loading and sample concentration has been studied and the system for gradient elution improved. Our work shows that two‐dimensional separation is the most reliable and informative method for preparation of homogeneous oligonucleotides. The hydrophobic‐pair ion‐exchange mechanism is proposed for ion‐pair chromatography. Protected and partially deblocked oligonucleotides, chemically synthesized for genetic engineering studies, have been separated with high selectivity by adsorption (normal‐phase) HPLC which is efficient for gradient elution with isohydric eluents. The analysis of a monomeric composition of nano‐(pico‐) molar amounts of oligonucleotides has been developed; the procedure involves microcolumn digestion of the oligonucleotides with immobilized enzymes followed by microcolumn separation of the nucleoside‐mononucleotide mixture. Also, a new slurry method for packing stable HPLC columns with a tightly consolidated, nonshrinkable bed of

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070802

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractA simple formula is derived which allows estimation of the band broadening due to longitudinal diffusion in retention gaps for isothermal runs with the column held at the injection temperature. The broadening is strongly dependent on the linear gas velocity in the retention gap. If the internal diameters of the retention gap and the separation column are similar, the retention gap may have a length exceeding 100 m, even if the separation column is only 10 m long. A 0.5 mm I.D. retention gap attached to a 0.3 mm I.D. separation column (of interest for automatic on‐column injection) may be several meters long. Retention gaps of 0.3 mm I.D. may be used for on‐column injections into separation columns with I.D's. down to about 0.1

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070803

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractA method for the quantitation of retinol in serum by normal phase high performance liquid chromatography is described. The mobile phase consists of a hexane/diethylether/methanol mixture with spectrophotometric detection. The sample preparation is similar to that described by other authors and involves protein precipitation followed by extraction and direct injection onto the chromatograph. Adequate sensitivity is achieved using 200 μl samples. The internal standard chosen is α‐naphthol because of its spectral similarities to retinol and its greater stability than the commonly used retinyl esters. The method has been successfully applied to the clinical evaluation of a number of malabsorption syndromes for which it is preferred to the measurement of total caroteno

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070804

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

摘要:

AbstractA method is described for quantitative determination of phospholipids of mitochondria following one‐dimensional thin‐layer chromatography without previous elution. Using high performance thin‐layer chromatography (HPTLC) and anin situfluorescence technique, the time needed for quantitative determination is relatively short. As the method is rather sensitive, small amounts of the extracts can be applied (about 200 ng of total phospholipids per spot). The reproducibility for the phospholipid fractions determined was in the range of 8–17%. The procedure was tested with lipid extracts of rat liver mitochondria. The method allows the determination of cardiolipin, phosphatidyl ethanolamine, phosphatidyl inositol, phosphatidyl choline, and sphing

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070805

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070806

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070807

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070808

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070809

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070810

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240070811

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1984

数据来源: WILEY