摘要:

AbstractThe analysis of low‐volatile polar nucleosides by (GC)2/FID and (GC)2/CI‐MS, employing HMDS‐deactivated glass capillary columns and on‐column injection, is described. The four linkage isomers of a specific nucleoside, formed in the synthetic procedure, are in each case sufficiently well separated in the chromatogram; GC/CI‐MS allows for a differentiation of N‐7 and N‐9 li

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030402

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

年代:1980

数据来源: WILEY

摘要:

AbstractMethanol, 2‐Me‐propanol‐2, propanol‐2, benzene, toluene and xylenes in gasoline blends were determined using a valveless multi‐dimensional switching system (MDSS) with two packed columns and temperature programming.Compounds of interest, interfering with paraffins and naphthenes, were in a sequence of four heart cuts transferred onto the second column. The resulting baseline separation enabled precise quantitative measurement within a short analysis time. Instrument settings, times of switching and integration parameters were stored in an instrument memory file (user table) and thus high precision in the measurements was

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030403

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

年代:1980

数据来源: WILEY

摘要:

AbstractGlass capillary columns coated with OV‐225 and Silar 10C were used to analyze estrogens (as their trimethylsilyl derivatives) present in pregnant mares' urine. Such columns provide better resolution in a shorter time than the corresponding packed columns, as exemplified by the separation of estrone from equili

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030404

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe “Distribution Function Method”, which makes possible the measurement of systematic variations in the shape of signals, has been experimentally tested on the detection of two visually confounded gas chromatographic peaks, irrespective of the estimation of the resolution or the concentration ratio. Two detection procedures are suggested. The first compares directly, under the same experimental conditions, the shape of a pure peak and that of a peak suspected of contamination. The second makes use of variations of column temperature and gas flow rates to distinguish the behaviour of a pure substance from that of a contaminated substance. A marking procedure for the shape of a pure peak is then set up to dispense with the need of a reference standard. In practice, the two procedures make possible the detection of heptane as an impurity inn‐hexane at levels of one percent and under experimental conditions artificially chosen so as to make the resolution inferior to

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030405

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe separation number is affected by a variety of extra‐column factors (e.g. the injection process, the nature of the sample, and plumbing defects in the inlet and detector) as well as factors related to column efficiency. The magnitude of the separation number, as affected by the column, varies inversely with column temperature and directly with the partition ratios of the test compounds. The interrelationships of column temperature and partition ratios are explore

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030406

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

年代:1980

数据来源: WILEY

摘要:

AbstractTLC experimental data have been measured for polycyclic hydrocarbons in binary and ternary mobile phases on silica gel. These data have been interpretated using the equation discussed by us in Part 1 of this series [HRC&CC 2 (1979) 236]. The heterogeneity parameter appearing in this equation has been evaluated and compared for different ternary and binary mobile phases.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030407

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

年代:1980

数据来源: WILEY

摘要:

AbstractChanges of fluorescence intensity at the far side (transmission) and near side (remission) in cases where a spot of a fluorogen lies in different sublayers are calculated using a multilayer model. Examples shown are: the relative intensity of fluorescence in the layer as a function of the absorption coefficient of a sorbent at the excitation wavelength; the relative intensity of fluorescence at the far and near sides of a TLC plate; the influence of using too broad a monochromatic filter at the emission side on the results of fluorescence measurements. Advantages of near‐side scanning of fluorescence compared to far‐side scanning are discussed. The most important source of errors in fluorodensitometric measurements is the effect of secondary chromatogra

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030408

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

年代:1980

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030409

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

年代:1980

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030410

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

年代:1980

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240030411

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

年代:1980

数据来源: WILEY