ISSN:0935-6304    

DOI:10.1002/jhrc.1240021002

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

年代:1979

数据来源: WILEY

摘要:

AbstractBoth the invention of the capillary drawing machine and the preparation and successful use of the first glass capillary column were achieved by Desty and his group in 1959.This paper attempts to describe the glass capillary column in a general way, including the spreading of liquid phases of different polarity and solid surfaces with different chemical and geometrical structures, and surface activity (as a source of essential column characteristjcs such as film stability, adsorptive and catalytic activity, acidity, and thermostability). The model is entirely based on experimental evidence. It is shown that today's apolar columns may closely approach ideal performance, such as is conceivable at the present time, while a severe gap still exists between the actual and the ideal characteristics of polar columns. The problem lies in the necessity of using considerably active support surfaces for polar coatings, yielding columns with reduced upper temperature limits, and of restricted suitability concerning the nature of sample. It is hoped that progress in the field of surface roughening may produce an inert support which is wettable by polar phases.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021003

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe time constant, τ, is determined from the tail of an authentic HPLC peak through a plot of In U versus time, t, according to the relation\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm In\, U} = {\rm In }\mathop {\rm U}\nolimits_{\rm o} - \frac{1}{\tau }{\rm \,t} $$\end{document}expected at low recorder deflexions, U. The value obtained, τ = 2.43 s, is one order of magnitude larger than an ordinary recorder time constant, which is quite normal for LC detectors. It agrees with the value, τ = 2.44 s, needed theoretically to distort a Gaussian‐shaped peak so as to obtain the experiment‐ally found second moment, σ2= 11.13 s,2and the experimental difference between first momenttand peak retention time tmax,t– tmax= 0.78 s. The determination is therefore regarded as a demonstration of the variance addition rule\documentclass{article}\pagestyle{empty}\begin{document}$$ \sigma ^2 = \sigma \frac{{\rm 2}}{{\rm G}} + \tau ^2 $$\end{document}where σ G2is the second moment of the non‐distorted peak. The column contribution version\documentclass{article}\pagestyle{empty}\begin{document}$$ (\sigma ')^2 = \sigma \frac{2}{{\rm o}}_{{\rm (k)}} + \sigma \frac{{\rm 2}}{{\rm s}} $$\end{document}is also considered. This equation was appliied earlier to an estimation of extra‐column contributions to band broadening with the aid of the “abt” concept. An explicitly k‐(capacity ratio)‐dependent expression for the mass exchange contribution, σ G2is derived from Golay's equation for capillary columns, but the validity of the Golay e

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021004

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe chromatographic properties of potassium fluoride as an additive to the polyethylene glycol stationary phase were investigated. This unique base in organic chemistry was shown to succeed in yielding good results for the analysis of polar compounds, including the primary amines. Glass capillary columns of high selectivity for primary and secondary aliphatic amines were obtained by the “hexane plug” procedure by which a thin layer of KF is deposited on the inner surface of glass capillary columns. Some possible types of donor‐acceptor interactions occuring within the system PEG/KF/solute were consi

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021005

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

年代:1979

数据来源: WILEY

摘要:

AbstractA detailed method for the routine preparation of glass capillary columns is presented. The method consists of coating a glass tube with quartz powder prior to pulling the tube into a capillary. The inner surface of the capillary consists of an even distribution of quartz particles fused to the walls. This surface has been found readily deactivated by standard procedures and ideal for the preparation of thick‐film glass capillary columns. The method has been thoroughly tested in two independent laboratories to ensure that the procedures described are reproducibl

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021006

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

年代:1979

数据来源: WILEY

摘要:

AbstractCatecholamine standards have been separated by ion pairing reversed‐phase high‐performance liquid chromatography (HPLC). A trace substance was separable from four standards when low concentrations of methanol were used in the elution buffer. This method has allowed separation of an unknown uterine catecholamine, partially purified on a boronate affinity gel column, from the standards: norepinephrine, epinephrine, normetanephrine and metanephr

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021007

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

年代:1979

数据来源: WILEY

摘要:

AbstractA synthetic mixture of uroporphyrin isomers I, II, III and IV as free acids in the synthetic ratio of 1:1:4:2 was resolved by reverse‐phase HPLC using a C0:PEL (ODS) 37‐50 micron precolumn and a Micro Bondapak C18 analytical column eluted with acetonitrile (4%) in phosphate buffer (pH 6.95). Clinically important I and III isomers of uroporphyrin were readily resolved directly from acidified urine as porphyrin free ac

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021008

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

年代:1979

数据来源: WILEY

摘要:

AbstractCircular high‐performance thin‐layer chromatography (HPTLC) has been used to differentiate a series of twelve tricyclic neuroleptics, using both normal phase and reverse phase procedures. The use of normal phase systems also allows the resolution of geometric isomers of chlorprothixene, clopenthixol and flupenthixol. Thirteen sulphonamides and Trirnethoprim may also be distinguished using HP

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021009

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

年代:1979

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021010

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

年代:1979

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240021011

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

年代:1979

数据来源: WILEY