Quantitative liquid chromatography

Almost all quantitative LC analyses are carried out using UV, BCD or F detection also MS, CLND, ELSD and SCD play a role. The UV detector is probably the detector of choice for quantitative analysis as it combines the essential features of wide linear dynamic range with fairly high sensitivity. Most antioxidant stabilisers, whether phosphites, hindered phenols, etc., exhibit UV absorptivity. Simultaneous multi-wavelength quantitation at unlimited different 

Also a variant of liquid chromatography, SEC, has been applied for quantitative analysis, although to a much lesser extent. Jickells [86] has exploited the use of SEC-FTIK for quantitative additive analysis. SEC separated mixtures can also be used as a direct sample input into a mass spectrometer for mass analysis. Cortes et al. [87] have introduced quantitative polymer/additive analysis by multidimensional chromatography using on-line coupled microcolumn SEC as a preliminary separation. A comparative quantitative study of dissolution and dissolution/precipitation of PC/(2,4-di-r-butylphenol, nonylphenol isomers, Tinuvin 329, Irgafos 168) and ABS/(nonylphenol isomers, Tinuvin P, benzylbutyl phthalate, Vanox 2246, Tinuvin 328/770, Topanol CA and Acrawax) by means of /rSEC-GC/LC has shown the quantitative reliability of the dissolution procedure [87]. It also appears that the precipitation technique can yield low results for additives which exhibit solubility dependence. Polymer additives may routinely be analysed 

Principles and Characteristics Chester et al. [89] have identified some eleven essential considerations for accurate and precise trace analysis by means of capillary SFC, matching HPLC precision. The key to trace analysis below 1 ppm with an FID is providing an injection volume of sufficient size (with complete avoidance of splitting). By injecting volumes up to 0.5 /u.L relative standard deviations of less than 0.3% for the injected volume are achieved with little or no sacrifice of chromatographic performance RSDs for solute areas of 2% are quoted. FID detection permits quantitation of well-shaped peaks as low as approximately 100 pg in mass, thus providing quantitation of sub-ppm solutes in the injection solvent. Packed column SFC, which uses standard size HPLC columns and hence standard HPLC injection systems, yields more reproducible quantitative results than cSFC. Cfr. also ref. [3a]. 

After Tikuisis and Cossar [95]. Reproduced by permission of the authors. 

On-line SFE-SFC-FID is also suited to quantitative analysis of dialkyltin additives in rigid PVC and is able to replace other tedious and time-consuming procedures. The results are highly reproducible. Table 7.14 of ref. [3a] shows other quantitative analyses of polymer additives by means of SFF-SFC. 

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Liang, H.R. Foltz, R.L. Meng, M. Bennett, P. Ionization enhancement in atmospheric pressure chemical ionization and suppression in electrospray ionization between target drugs and stable-isotope-labeled internal standards in quantitative liquid chromatography/tandem mass spectrometry. Rapid Commun. Mass Spectrom. 2003, 17, 2815—2821. 

Takino, M., Daishima, S., Yamaguchi, K., and Nakahara, T. (2003). Quantitative liquid chromatography-mass spectrometry determination of catechins in human plasma by automated on-line extraction using turbulent-flow chromatography. Analyst 128 46-50. 

After neutralization, the dinitramide is separated from the other anions, nitrate and sulfate, by quantitative liquid chromatography. 

GK Poon, G Kwei, R Wang K Lyons, Q Chen, V Didolkar, CECA Hop. Integrating qualitative and quantitative liquid chromatography/tandem mass spectrometric analysis to support drug discovery. Rapid Commun Mass Spectrom 13 1943-1950, 1999. 

Haginaka, J. Wakai, J. Liquid chromatographic determination of ampicillin and its metabolites in human urine by postcolumn alkaline degradation. J.Pharm.Pharmacol., 1987, 39, 5-8 Margosis, M. Quantitative liquid chromatography of ampicillin collaborative study. J.Assoc.Off. Anal.Chem., 1987, 70, 206-212... 

Zhang ZY, King BM, Wong YN. Quantitative liquid chromatography/mass spectro-metry/mass spectrometry warfarin assay for in vitro cytochrome P450 studies. Anal Biochem 2001 298 40-49. 

Lanckmans K, Sarre S, Smolders I, Michotte Y. Quantitative liquid chromatography/ mass spectrometry for the analysis of microdialysates. Talanta 2008 74 458—69. 

Ruibal-Mendieta, N.L., Rozenberg, R., Delacroix, D.L., Petitjean, G., Dekeyser, A., Baccelli, C., Marques, C., Delzenne, N.M., Meurens, M., Habib-Jiwan, J.L. and Quetin-Leclercq, J., Spelt Triticum spelta L.) and winter wheat (Triticum aestivum L.) wholemeals have similar sterol profiles, as determined by quantitative liquid chromatography and mass spectrometry analysis. J. Agric. Food Chem., 52,4802-4807 (2004). 

This publication provides several examples of the use of solid-phase extractions for separating analytes from their matrices. Some of the examples included are caffeine from coffee, polyaromatic hydrocarbons from water, parabens from cosmetics, chlorinated pesticides from water, and steroids from hydrocortisone creams. Extracted analytes maybe determined quantitatively by gas (GC) or liquid chromatography (LG). 

High Pressure Liquid Chromatography. This modem version of the classical column chromatography technique is also used successfully for separation and quantitative analysis of dyes. It is generally faster than thin-layer or paper chromatography however, it requires considerably more expensive equipment. Visible and uv photometers or spectrophotometers are used to quantify the amounts of substances present. 

Typically, quantitative protein determination is done on the one hand by colorimetric or nephelometric methods, on the other hand for more difficult analytical problems by more sophisticated techniques such as high performance liquid chromatography (HPLC), gel-electrophoresis and immunoassay. However, these methods are tedious, time-consuming and expensive. 

A liquid chromatography-mass spectrometry (LC-MS) method that can quantitatively analyze urinar y normal and modified nucleosides in less than 30 min with a good resolution and sufficient sensitivity has been developed. Nineteen kinds of normal and modified nucleosides were determined in urine samples from 10 healthy persons and 18 breast cancer patients. Compounds were separ ated on a reverse phase Kromasil C18 column (2.1 mm I.D.) by isocratic elution mode using 20 mg/1 ammonium acetate - acetonitrile (97 3 % v/v) at 200 p.l/min. A higher sensitivity was obtained in positive atmospheric pressure chemical ionization mode APCI(-i-). 

Liquid chromatography was performed on symmetry 5 p.m (100 X 4.6 mm i.d) column at 40°C. The mobile phase consisted of acetronitrile 0.043 M H PO (36 63, v/v) adjusted to pH 6.7 with 5 M NaOH and pumped at a flow rate of 1.2 ml/min. Detection of clarithromycin and azithromycin as an internal standard (I.S) was monitored on an electrochemical detector operated at a potential of 0.85 Volt. Each analysis required no longer than 14 min. Quantitation over the range of 0.05 - 5.0 p.g/ml was made by correlating peak area ratio of the dmg to that of the I.S versus concentration. A linear relationship was verified as indicated by a correlation coefficient, r, better than 0.999. 

Ealke, S. T. (1984). Quantitative Column Liquid Chromatography A Survey of Chemometric Methods. Elsevier, Amsterdam. 

In this context it is important to note that the detection of this land of alkali cation impurity in ionic liquids is not easy with traditional methods for reaction monitoring in ionic liquid synthesis (such as conventional NMR spectroscopy). More specialized procedures are required to quantify the amount of alkali ions in the ionic liquid or the quantitative ratio of organic cation to anion. Quantitative ion chromatography is probably the most powerful tool for this kind of quality analysis. 

The malonaldehyde thus formed can be estimated quantitatively by the thiobarbituric acid method (58, 59). As a control of the method s reliability, we used, as primary standard, 1, 3, 3-tri-ethoxypropene (46, 47) purified by gas-liquid chromatography (56) and hydrolyzed to malonaldehyde at room temperature with IN sulfuric acid. The molar... 

Chromatography is a separation process employed for the separation of mixtures of substances. It is widely used for the identification of the components of mixtures, but as explained in Chapters 8 and 9, it is often possible to use the procedure to make quantitative determinations, particularly when using Gas Chromatography (GC) and High Performance Liquid Chromatography (HPLC). 

The present chapter is largely concerned with HPLC, together with a summary of developments in quantitative thin-layer chromatography, but a brief account of the various types of liquid chromatography is given first together with a guide to the choice of appropriate separation mode. 

High performance liquid chromatography is used for the separation and quantitative analysis of a wide variety of mixtures, especially those in which the components are insufficiently volatile and/or thermally stable to be separated by gas chromatography. This is illustrated by the following method which may be used for the quantitative determination of aspirin and caffeine in the common analgesic tablets, using phenacetin as internal standard where APC tablets are available the phenacetin can also be determined by this procedure. 

It should be noted here that the difficulty of accurately injecting small quantities of liquids imposes a significant limitation on quantitative gas chromatography. For this reason, it is essential in quantitative GLC to use a procedure, such as the use of an internal standard, which allows for any variation in size of the sample and the effectiveness with which it is applied to the column (see Sections 9.4(5) and 9.7). 

Column chromatography see Chromatography Columns in gas chromatography, 238 in liquid chromatography, 223 Combustion flames 784 Common ion effect 26 quantitative effects of, 35 Comparators permanent colour standards,... 

To measure gas and water vapor permeability, a film sample is mounted between two chambers of a permeability cell. One chamber holds the gas or vapor to be used as the permeant. The permeant then diffuses through the film into a second chamber, where a detection method such as infrared spectroscopy, a manometric, gravimetric, or coulometric method isotopic counting or gas-liquid chromatography provides a quantitative measurement (2). Die measurement depends on the specific permeant and the sensitivity required. 

The Tools of Proteomics A variety of methods and techniques including two-dimensional gel electrophoresis (2DE), capillary liquid chromatography, stable isotope labeling, and mass spectrometry has been developed for qualitative and quantitative protein... 

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