Determination using high pressure liquid chromatography

2 Determination Using High Pressure Liquid Chromatography 

For carrying out routine high pressure liquid chromatography separation, it is the reversed-phase method which is most suitable, and in particular using RP 8 or RP 18 columns. These materials are based on silica gel with a chemically bonded, non-polar stationary phase of differing polarity. 

The various commercially available ready-made columns do not always give the same separation results and so no general statement can be made about the success of separation. For elution, an approx, 83 13 (v/v) methanol/ water mixture is used. Under these conditions it often proves impossible to separate benzo(b)fluoranthene and benzo(k)fluoranthene. Preliminary treatment of the water samples is the same as described above. 

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Francesconi, K.A., P. Micks, R.A. Stockton, and K.J. Irgolic. 1985. Quantitative determination of arsenobe-taine, the major water-soluble arsenical in three species of crab, using high pressure liquid chromatography and an inductively coupled argon plasma emission spectrometer as the arsenic-specific detector. Chemosphere 14 1443-1453. 

H. G. Barth and A. Z. Conner, Determination of doxorubicin hydrochloride in pharmaceutical preparations using high-pressure liquid chromatography, J. Chromatogr., 131 375 (1977). 

H. A. Adams, B. Weber, M. B. Bachmann, M. Guerin, and G. Hempelmann, The simultaneous determination of ketamine and midazolam using high pressure liquid chromatography and UV detection (HPLC/UV), Anaesthesist, 47 619 (1992). 

Samples containing 150 g of 500 ppm acids were also prepared using 3% added sodium chloride in the 90/10 oil/water blend, water, and vegetable oil as the microwave medium. These samples were heated 0, 1, 2, and 3 minutes in the microwave. Changes in the acid concentration were determined by high pressure liquid chromatography with an organic acid column and an aqueous mobile phase. 

M. J. Powell, D. W. Boomer, and D. R. Wiedcrin. Determination of chromium species in environmental. samples using high-pressure liquid chromatography direct injection nebulization and inductively coupled plasma mass spectrometry. Anal. Chern., 67, 2474,1995. 

Cole, R. A., Soeldner, J. S., Dunn, P. J., and Bunn, H. F., A rapid method for the determination of glycosylated hemoglobins using high pressure liquid chromatography. Metabolism 27, 289-301 (1978). 

Canon, A.B. and M.S. Erank The determination of certain C1-C4 aldehydes in cigarette smoke using high pressure liquid chromatography 32" Tobacco Chemists ... 

Francesconi, K.A., Micks, P., Stockton, R.A. and Irgolic, K.J. (1985). Quantitative Determination of Arsenobetaine, the Major Walter-Soluble Arsenical in Three Species of Crab. Using High Pressure Liquid Chromatography and an Inductively Coupled Argon... 

Reusability of the Electrode. Reusability of the microbial electrode was examined with the sample solution containing 125 r /mi of phenyl acetyl-7ADCA. The results obtained are shown in Figure 6. The cephalosporin determination was performed several times a day. However, no decrease of the potential difference was observed for a week. This system was applied to the determination of cephalosporins in a fermentation broth. Cephalosporin C in the cephalospolium acremonium broth was determined by the conventional method using high pressure liquid chromatography (HPLC) (13) and the electrochemical method. The results obtained are shown in Table 1. The relative error of the determination by the microbial electrode was within 10 %. Therefore, this system can be used for the continuous determination of cephalosporin in a fermentation broth. 

Each model was applied to sugar attenuation data taken from multiple brewing fermentations (assessed using high-pressure liquid chromatography). Three techniques Akaike s (corrected) Information Criterion, comparison of the coefficients of determination (r ) and absolute residual sum of squares (RSS) were used to compare the fit of each model. Ideally, the data would adhere to a simplistic, theoretically derived formula such as a low parameter symmetric model. Unfortunately, the variability in both shape and lag time for each individual sugar necessitated a more flexible... 

While the use of one terpyridine monomer results in only one dimeric complex, the use of more than one monomer leads to a mixture of complexes. Two monomers (X and Y) will lead to 25% dimeric X X, 25% dimeric Y Y, and 50% mixed complex X Y determined by high-pressure liquid chromatography (HPLC) of reaction products. Complexes (X Y) and (Y X) are degenerate and only one need be considered. Each bis(terpyridine) metal complex exists as a pair of stereoisomers due to the two possible arrangements around the metal center, and no attempt was made to distinguish or separate these stereogenic pairs. The total number of components of these combinatorial libraries must include both symmetric and asymmetric complexes. If n terpyridine monomers are combined, the same number of symmetric complexes (X X) are formed. The number of asymmetric complexes (X Y) formed is /[( -2) 2 ] or better represented as n(n-l)/2. Thus the total number of dimeric complexes is the sum of n and ( -l)/2, which is n(n+l)/2. For example, a library with 5 monomers will form 15 dimers, 10 monomers will produce 55 dimers, and 20 monomers will produce 210 dimers. 

Heinze, T. Kynast, G. Dudenhausen, J.W. Baling, E. Effect of blood and meconium on the determination of phospholipids in amniotic fluid using high pressure liquid chromatography, J.Perinat.Med., 1988,... 

Biochemical analyses of 6-OHDA-injected animals revealed a 93 percent depletion of dopamine. The tissue was assayed using electrochemical detection following separation by high-pressure liquid chromatography (Felice et al. 1978). recorded as ng/mg protein in the nucleus accumbens and compared to control rats with sham lesions (sham=65.5 4.4, lesion=4.9 1.5 t(39)=23.4). A lesion was defined as complete if 75 percent or more of the dopamine was determined to be depleted from the nucleus accumbens compared to mean sham group values. 

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... 

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