High-pressure liquid chromatography applications

CF Aten, JB Bourke, RA Marafioti. Determination of thiophanate methyl as carbendazin by high-pressure liquid chromatography application to onions and cabbage. J Agric Fd Chem 30 610-611, 1982. 

Brown, P.R. "High Pressure Liquid Chromatography, Biochemical and Biomedical Applications", Academic Press, New York, 1973. 

Timbie, D., Sechrist, L., Keeney, P., Application of high pressure liquid chromatography to the study of variables affecting theobromine and caffeine concentrations in cocoa beans, J. Food Sci., 43, 560, 1978. 

The values of ks/kp for partitioning of carbocations are most conveniently determined as the ratio of the yields of products from the competing nucleophile addition and proton transfer reactions (equation 1 derived for Scheme 2). The determination of these product yields has been simplified in recent years by the application of high-pressure liquid chromatography (HPLC). Typically, the product peaks from an HPLC analysis are detected and quantified by UV-vis spectroscopy. In cases where the absorbance of reactants and products is small, substrates may be prepared with a chromophore placed at a sufficient distance so that its effects on the intrinsic reactivity of the carbocationic center are negligible. For example, the aliphatic substrates [1]-Y have proved to be very useful in studies of the reactions of the model tertiary carbocation [1+].21,23... 

Relationships such as Eqs. (45) and (46) have been utilized extensively in correlating solubility properties (such as gas/liquid and liquid/liquid partition coefficients), retention volumes in gas/solid chromatography, capacity factors in high-pressure liquid chromatography, etc.199 200 For instance, gas/liquid partition coefficients for each of 35 different liquid stationary phases were represented with R > 0.985.205 Other applications have been in biochemical and pharmacological areas,199 200 e.g., enzyme inhibition and pollutant effects. 

J Rivier, R Wolbers, R Burgus. Application of high pressure liquid chromatography to peptides, in M Goodman, J Meienhofer, eds. Peptides. Proceedings of the 6th American Peptide Symposium. Halsted, New York, 1977, pp 52-56. 

Since its creation around 1973, modern high-pressure liquid chromatography (HPLC) has played a dominant role in the analysis of pharmaceuticals. It is used in many different applications for example, in content uniformity assays and stability-indicating methods, for the purity profiles of drug substances, or in the analysis of drug metabolism in animals and humans. The heart of all of these assays is the HPLC column. In this chapter, we will describe the fundamental properties of HPLC columns as well as how these properties influence column performance and separation characteristics in pharmaceutical assays. 

Marin JM, Gracia-Lor E, Sancho JV et al (2009) Application of ultra-high-pressure liquid chromatography-tandem mass spectrometry to the determination of multi-class pesticides in environmental and wastewater samples Study of matrix effects. J Chromatogr A 1216 1410-1420... 

The application of atomic spectroscopic instruments as element-specific detectors in chromatography has been reviewed by van Loon More recently, Krull has extensively reviewed their use in high pressure liquid chromatography (HPLC). Atomic spectrometry has found wide acceptance in the field of liquid chromatography because, in most cases, the fractions can be directly analysed after elution from the column. However, it is possible to use the technique for the analysis of solid samples without first dissolving the matrix. This is particularly useful after electrophoresis, where the fractions are fixed either in a gel or on paper. Kamel et al. have shown that it is possible to cut the appropriate sections and insert them into the carbon furnace for analysis. The disadvantage of this approach is that the precision is usually poorer (about 10%) and it is difficult to calibrate the instrument. Nevertheless, this approach is very useful if it is used for qualitative speciation. 

A further major application of solvents in organic chemistry is in high-pressure liquid chromatography (HPLC), for the chromatographic separation of solutes, be it for preparative or analytical purposes. 

The application of modem methods of analyses such as gc, low ionization voltage mass spectrometry, high pressure liquid chromatography (hplc), and nmr has greatly increased knowledge of coal-tar composition without materially altering the qualitative picture. 

Internal reflection spectroscopy is widely applied for on-line process control. In this type of application, the chemical reactor is equipped with an internal reflection probe or an IRE. The goal of this type of application is the quantification of reactant and/or product concentrations to provide real-time information about the conversion within the reactor. In comparison with other analytical methods such as gas chromatography, high-pressure liquid chromatography, mass spectrometry, and NMR spectroscopy, ATR spectroscopy is considerably faster and does not require withdrawal of sample, which can be detrimental for monitoring of labile compounds and for some other applications. 

Some particular processes can require very high pressures for special applications (i.e. in explosive welding and plating), but pressures between 100 and 1000 bar can be found easily in different industrial processes. Typical examples are the synthesis of ammonia, the synthesis of methanol and the production of low-density polyethylene, but also analytical techniques as high-pressure liquid chromatography. Other important implications are for the storage and transportation of fluids and enhanced oil recovery. 

I Stober, HR Schulten. Combined application of high-pressure liquid chromatography and field desorption mass spectrometry for the determination of biocides of the phenylurea and carbamate type in surface water. Sci Total Environ 16 249-262, 1980. 

Pharmacokinetic studies (e.g. plasma levels in dogs after peroral or intravenous application, tissue distribution in the rat after intravenous administration) with 44 in several animals have been carried out using l4C-labelled diphenylsilanediol and high pressure liquid chromatography. The elimination half-lives were found to be 1.7 h in mice, 7.2 h in rats, and 6.5 h in dogs after peroral application. 

B. P. Chattopadhyay, J. Chattopadhyay, and P. C. Bose, Application of high pressure liquid chromatography for simultaneous estimation of aminophylline, codeine, ephedrine, and diphenhydramine in cough syrup, Indian Drugs, 22 154 (1984). 

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