Capillary columns, high resolution capability

While it is clearly apparent that packed columns are mainly used for the various compendial tests, the use of capillary columns for the determination of therapeutic agents in biological fluids has become increasingly popular. The high resolution capability of capillary columns often overcomes the problems of interference from the biological sample matrix and, coupled with specificity and increased sensitivity has made possible the quantitative analysis of many, formerly undeterminable drugs in biological fluids. In particular. 

The increasingly rapid adoption of capillary column GC techniques promises an advance for inorganic separations as much by virtue of the absence of decomposition sites on supports or columns as by high resolution capabilities. This is particularly true for fused-silica capillary columns, which are characterized by extremely low residual trace metal concentrations in the silica matrix. 

We have recently explored the application of glass capillary gc to trimethylsilyl (tms) ether derivatives of pyrrolizidine alkaloids. The high resolution capabilities of capillary columns offered promise in separating the complex and closely related alkaloid mixtures often encountered in plant extracts. The gc trace shown in Figure 5 illustrates the application of a capillary system to a mixture of tms-ethers of the 12 pure macrocyclic di-ester alkaloids shown in Figures 2 and 3. 

A significant step in the evolution of analytical pyrolysis was the combination of pyrolysis with a sophisticated physiochemical technique for the efficient separation and/or identification of the fragments. In 1959, a combined Py/GC system of polymers was introduced. Improvements in the analysis conditions were obtained by using the high-resolution capabilities of capillary columns. In 1970, a continued interest in the analysis of extraterrestrial samples such as lunar rocks and the Allende me-terorite (found in Mexico) was reported, using the modified Py/GC/MS technique. Applying a pyrolysis/mass... 

GC-MS using high-resolution capillary columns and low-resolution mass spectrometers has been a popular analytical technique in environmental organic geochemistry [507,572,573]. However, additional analytical techniques have been used very recently to extend the capabilities available for the determination of molecular markers. Such advances are discussed in the next few paragraphs, which show the alternative approaches to increase GC-MS sensitivity and specificity ... 

There is considerable current interest in development of state-of-the-art methodology for characterization of PAHs in various matrices (.l). Gas chromatography and gas chromatography-mass spectrometry are two techniques widely used for PAH analysis because the necessary equipment is available in most laboratories. The development of high resolution glass capillary columns has significantly advanced the compound-characterizing capability of these techniques. 

High resolution capillary columns are used to resolve as many PCDD/PCDF isomers as possible. No single column is known to resolve all 210 of the isomers. The columns employed by the laboratory in these analyses must be capable of resolving the 17 2,3,7,8-substituted PCDDs/PCDFs sufficiently to meet die method specifications (see Section 7.1). 

Applications of cze include the detection of trace amounts of DNA and the separation of peptide fragments. Furthermore, this technique is beneficial to forensic scientists because restriction mapping can be performed, allowing assays for DNA to be carried out at the scene of a crime (see Forensic testing). It is also possible to interface capillary electrophoresis on-line with a mass spectrometer as a sample introduction technique in the analysis of amino acids and proteins (70). Further improvements in capillary electrophoresis include the need to increase column capacity. Most reported separations involve the resolution of only 20—30 components, whereas high resolution hplc is capable of resolving several hundred components in a mixture (see Chromatography). 

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