ISSN:0935-6304    

DOI:10.1002/jhrc.1240010102

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

年代:1978

数据来源: WILEY

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010103

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

年代:1978

数据来源: WILEY

摘要:

AbstractPractical details are given to produce low dead volume Pt/Ir to glass connections and a variety of components for effluent splitting and pneumatic solute switching. It is shown that the column effluents from a glass capillary column can be split in any desired ratio and maintained constant, regardless of column flow rate. Bandbroadening in the splitter remains negligible even for very low flow rates. A complex pneumatic system to be used for heartcutting with two glass capillary columns is shown.

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010104

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

年代:1978

数据来源: WILEY

摘要:

AbstractHPLC‐separation using a reversed‐phase system is described for phytosterols, pentacyclic triterpenoid acids, ‐diols and –

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010105

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

年代:1978

数据来源: WILEY

摘要:

AbstractMicro capillary columns were successfully applied to liquid chromatography by employing the principles used in micro high performance liquid chromatography. Fundamental investigations on the use of capillary columns in LC were performed for the various column parameters. Good separations of five aromatic hydrocarbons and four kinds of phthalic esters were obtained on a 62 μm I.D. capillary column, coated with SE‐

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010106

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

年代:1978

数据来源: WILEY

摘要:

AbstractGrowing whiskers on the inner wall of glass capillary columns is an easy roughening technique which allows efficient coating of the columns with any stationary phase. The advantages and disadvantages of whisker surfaces are discussed. Several examples are presented to illustrate the possibilities of whisker‐wall coated open tubular (WWCOT) column

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010107

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

年代:1978

数据来源: WILEY

摘要:

AbstractA rapid and sensitive method to determine volatile organohalides in different types of waters has been developed. The chromatographic system is based on the resolving power of the glass capillary column and the high sensitivity of the electron capture detector. The capillary columns were connected to the detector so that the eluate from the column is mixed with thermostatted purge gas to minimize band broadening due to dead volumes. The low column bleeding and decreased band spreading from capillary columns enhance the sensitivity to very low levels: 1 fg (10−15g) for carbon tetrachloride, despite dilution of the column eluate by the purge gas.The water samples of 100 ml were extracted with 1 to 10 ml n‐pentane which is the most practical alkane with respect to purity. When using high water to pentane ratios corrections had to be made, due to low extraction yield, to get accurate quantifications.A column with Carbowax 400 stationary phase permits direct tap water injection. The water peak concealed the substances eluated after CHCl3and CHBrCl2.The gas chromatographic separation of haloforms in tap water could be shortened to 30 seconds using a 10 m SE–52 column with an increased film thickness.Besides tap water and seawater, industrial waste water from a pulp mill was analyzed. Ten different halogenated organic compounds, ranging from 1 ng/I to 760 μg/I, were quantified in the different waters. Bromoform, which had not previously been found in seawater, was detected.Chromatogram of a standard mixture containing 11 organohalides. Stationary phase, SE‐52; 33 m × 0.3 mm i.d. inj. temp. 200°, column temp. 50°, interface 250°, detector temp. 250°. Helium carrier gas flow rate, 36 cm/s, scavenger'gas flow 30 ml/min.Split ratio 1:20, 1 = CH2CI2, 2 = CHC13, 3 = CH3CC13, 4 = CC14, 5 = CHCICCI2, 6 = CHBrCI2, 7 = CBrC13, 8 = CHBr2Cl, 9 = CCl2CC12, 10 = CHCl2

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010108

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe real plate number concept is interpreted in terms of the fundamental properties of a chromatograph. It is shown that the linear relationship between the total peak width at half height, (b0.5)T, t, and k is only an approximation of the more general linear relationship between (b0.5)2T, t and (1 + k)2. In the case where the relationship between (b0.5)T, t and k approaches linearity, it is concluded, firstly, that b0= a, i. e., b0is a column property and independent of extra‐column phenomena and, secondly, that nreal=ntheor. When the relationship becomes non‐linear, b0is determined partly by extra‐column phenomena, but not in terms of a useful relationship. It is concluded that it is unnecessary to introduce the parameters a, b0and nreal, since they all have counterparts in the established theory of chromatography. These counterparts prove to be equally useful in the practical analysis of chromatographic sy

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010109

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

年代:1978

数据来源: WILEY

摘要:

AbstractVolatile fatty acids in aqueous media were esterfied in situ with phenyldiazomethane (PDM). Complete esterification was achieved in 3 h at 40°C under continuous stirring of an ether/water system. The process involved immediate transfer of benzyl esters into the organic phase. The separation of benzyl esters mixtures was carried out in glass capillary GC columns. The retention data and FID molar responses were determined for C1 to C6 acid benzyl esters, including 2‐methylpropionic, 3‐methylbutyric, 2‐methylvaleric, and 2‐ethylbutyric acid. An unusual relationship was observed between benzyl ester relative molar responses and carbon ato

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010110

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

年代:1978

数据来源: WILEY

摘要:

AbstractAnalysis of trimethylsilylethers of methyl esters of bile acids exhibits high separation efficiency with a 20 m × 0.3 mm glass capillary column covered with a crystal layer of barium carbonate and coated with polyethyleneglycol 20000 as liquid phase [3]. The sensitivity and reproducibility of this method can be further improved by an on‐column injection technique according to Grob et al. [

ISSN:0935-6304    

DOI:10.1002/jhrc.1240010111

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

年代:1978

数据来源: WILEY