Catecholamines chromatography

Felice, L. Felice, J. and Kissinger, P. Determination of catecholamines in rat brain parts by reverse-phase ion-pair liquid chromatography. 

Mitsui, A., Nohta, H., and Ohkura, Y., High-performance liquid chromatography of plasma catecholamines using 1,2-diphenylethylenediamine as precolumn fluorescence derivatization reagent, /. Chromatogr., 344, 61, 1985. 

Fenn, R. J., Siggia, S., and Curran, D. J., Liquid chromatography detector based on single and twin electrode thin-layer electrochemistry application to the determination of catecholamines in blood plasma, Anal. Client., 50, 1067,1978. 

Chi JD, Odontiadis J, Franklin M. 1999. Simultaneous determination of catecholamines in rat brain tissue by high-performance liquid chromatography. J Chromatogr B 731 361... 

Raggi MA, Sabbioni C, Casamenti G, Gerra G, Calonghi N, et al. 1999. Determination of catecholamines in human plasma by high-performance liquid chromatography with electrochemical detection. J Chrom B 730 201-211. 

Tornkvist A, Sjoberg PJ, Markides KE, Bergquist J. 2004. Analysis of catecholamines and related substances using porous graphite carbon as separation media in liquid chromatography tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 801 323. 

Fio. 51. Dependence of retention of catecholamines on volume percent acetonitrile in hetaeric chromatography. The ehient is water-acetonitrile at the volume percent indicated containing 0.2% (v/v) sulfuric acid and 0.1% (w/v) sodium dodecyl sulfote. The catecholamines separated are noradrenaline (NA), adrenaline (A). L-3,4-dihydroxyphenylalanine (LD), normetanephrine (NMA), dopamine (DA), metadrenaline (MA), and 3-methoxytyramine (MDA). Column 5- tm octadecyl silica treated with triroethylchlorosilane, 125 X 5 mm i.d. Reprinted with permission from Knox and Jurand (223). ... 

Starkey, J. A., Mechref, Y, Muzikar, J., McBride, W. J., and Novotny, M. V., Determination of salsolinol and related catecholamines through on-line preconcentration and liquid chromatography/atmospheric pressure photoionization mass spectrometry. Analytical Chemistry 78(10), 3342-3347, 2006. 

Hjemdahl P. Catecholamine measurements by high-performance liquid-chromatography. American Journal of Physiology 247, E13-E20, 1984. 

Assay of catecholamines in urine by ion exchange chromatography with electrochemical detection... 

More definite evidence for the transient existence of the un-cyclized l-(jS-aminoethyl)-3,4-benzoquinones has been obtained recently by Kodja and Bouchilloux,77 78 who noted that a transient yellow color (Amax ca. 385 mp) was occasionally observed during the enzymic oxidations of catecholamines (particularly in unbuffered systems at low temperatures). This phenomenon was probably due to the formation of the transient o-quinones. (The absorption maximum of o-benzoquinone, the effective chromophore of the open-chain quinones, is known to occur at ca. 390 mp.79) An absorption maximum at 390 mp is characteristic of the formation of the dopa-quinone chromophore during oxidation of small C -terminal tyrosine peptides in the presence of tyrosinase.37 48 Similar spectroscopic features were observed when the oxidations were carried out with lead dioxide in sulfuric acid solutions (pH> 1). If the initial oxidation was carried out for a short period of time, it was possible to regenerate the original catecholamines by reduction (e.g. with sodium bisulfite, potassium iodide, and zinc powder) and to show that the 385 mp peak disappeared.77,78 Kodja and Bouchilloux were also able to identify 2,4-dinitrophenylhydrazones of several of the intermediate non-cyclized quinones by paper chromatography and spectroscopy (Amax n weakly acid solution ca. 350 mp with a shoulder at ca. 410 mp).77,78... 

Anggard, E. and Goran, S., Gas chromatography of catecholamine metabolites using electron capture detection and mass spectrometry, Anal. Chem., 41, 1250, 1969. 

Kawai, S. and Tamura, Z., Gas chromatography of catecholamines as their trifluoroacetates, Chem. Pharm. Bull., 16, 699, 1968. 

Moffat, A.C. and Horning, E.C., A new derivative for the gas-liquid chromatography of picogram quantities of primary amines of the catecholamine series, Biochem. Biophys. Acta, 222, 248, 1970. 

Reversed-phase chromatography is the most popular mode for the separation of low molecular weight (<3000), neutral species that are soluble in water or other polar solvents. It is widely used in the pharmaceutical industry for separation of species such as steroids, vitamins, and /3-blockers. It is also used in other areas for example, in clinical laboratories for analysis of catecholamines, in the chemical industry for analysis of polymer additives, in the environmental arena for analysis of pesticides and herbicides, and in the food and beverage industry for analysis of carbohydrates, sweeteners, and food additives. 

The suprahypothalamic neurotransmitter level can be assessed by a determination of catecholamines in circumscribed brain areas, the technique requires preparation of frozen tissue and isolation of specific nuclei by the micropunch technique. The catecholamines and indolamines can be measured by a radio-enzymatic methods and by a high-pressure liquid chromatography (HPLC) with electrochemical detection. These mechanistic investigations are mostly initiated due to questions arising from the receptor interaction profile of the drug candidate, they may be required to prove that such receptor interactions truly change the functional state of neurotransmitters (functional expression). Mostly, however, the peripheral effects of such neurotransmitter mechanisms (for instance prolactin secretion) are sufficiently distinct. 

Zhang, W.Z., He, L.J., Gu, Y.L., Liu, X., and Jiang, S.X. 2003. Liquids as mobile phase additives on retention of catecholamines in reversed-phase high-performance liquid chromatography. Analytical Letters, 36 827-38. 

The assay, which measured only the amount of AD formed, used ion-paired, reversed-phase HPLC chromatography. The separation was carried out on a C18 (Nucleosil) column with a mobile phase of 0.1 M sodium phosphate buffer (pH 2.3-3.5) containing 5 mM sodium pentanesulfonate as the counterion to form ion pairs with the catecholamines, and 0.5% (v/v) acetonitrile. The separation of NA from AD is shown in Figure 9.14. 

Solid phase extraction. With the availability of pre-prepared cartridges of silica-based adsorbents, the use of solid phase extraction has increased in the last few years although the technique has been in use for many years for the isolation of many biochemicals, e.g. amino acids, catecholamines. In essence it is a version of chromatography conditions for the selective adsorption of the analytes (column, solvent, pH, etc.) are chosen, the sample is applied to a column, washed and the analytes selectively eluted with appropriate solvents. Since the columns are disposable there is no need to worry about protein contamination or infection. The adsorbents available cover an even wider range than HPLC materials since they are not required to withstand high back pressures. It is possible... 

Electrochemical detectors are based upon the volta-metric oxidation or reduction of separated analytes at a micro- or thin-film electrode. A number of pharmacologically active compounds that are aldehydes, ketones, or quinones (such as doxorubicin), or nitro compounds (such as nitrofurantoin) are amenable to reduction at a mercury or platinum electrode electron-rich indole derivatives and catecholamines can be oxidized at these electrodes. An important condition that must be fulfilled for electrochemical detection to be practicable is that the mobile phase must be capable of conducting an electrical current. This makes electrochemical detection particularly useful in reversed-phase liquid chromatography, where buffered water mixed with one or more organic cosolvents is usually the mobile phase. 

The DA neurons were initially identified by Sulston and coworkers, who used the catecholamine-specific technique of formaldehyde-induced fluorescence (FIF) (23). DA cell bodies and processes were visualized using fluorescence microscopy, confirmed as DA by aluminaabsorptionandthin-layerchromatography (TLC). The precursor L-DOPA was also identified but not the catecholamines norepinephrine and epinephrine. Based on FIF micrographs and worm DA content as well as the estimated volume of the cell bodies and processes, the concentration of DA in the nerve endings is predicted to be very similar to the concentration within mammalian varicosities (23). We and others [(6) R. Nass, unpublished data] have confirmed via high-perfomance liquid chromatography (HPLC) that DA and its metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) are present in the animal. 

Earlier fluorometric methods for analysis of urinary free catecholamines have been replaced by HPLC methods that allow selective quantitation of epinephrine, norepinephrine, and dopamine. Preliminary extraction of urine is stid required and numerous preanalytical cleanup techniques are available. An alumina extraction procedure is typically coupled with ion-exchange or adsorption chromatography. Alumina pretreatment usually involves a batch extraction technique in which catechols are first adsorbed at pH 8.6 and then eluted with boric acid, which forms a complex with cis-diol groups. Purification on boric acid affinity gels provides an alternative procedure for selective adsorption of catecholamines. 

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