Rapid analysis

Rapid analysis is a very important direction in gas chromatography [23-28]. ALOT columns can be used for fast gas analysis [23]. According to Tijssen and co-workers [23] the minimum analysis time can be determined with the following equation  

Examples of fast chromatographic separation are shown in Fig. 2-4 [23]. Columns were coated with submicrometer silica particles according to a slightly modified method originally developed by Schwartz and co-workers [24] and Cramers and co-workers [25]. 

Trace a (Fig. 2-4) was obtained with a virtually straight column, having a relatively wide inner diameter (0.54 mm). Trace b shows that the same columns but tightly colled into a helical shape, performs much better. Thus the favorable coiling effects in high-speed chromatographic separation 

Mobile phase — nitrogen, temperature — 23°C, split ratio 1 1000. 

Trace a methane, n-hexane, and n-pentane in a straight column (0.027 cm radius, 501 cm length) pressure drop 0.5 bar. Trace b same separation in the same column as under (a) but now tightly coiled 0.4 cm (coil radius) pressure drop 0.5 bar. Trace c methane, n-pentane, and n-hexane in a microcapillary column (0.0082 cm radius, 299 cm length) tightly coiled into a coil of 0.1 cm radius pressure drop 2 bar. 

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A second approach to coulometry is to use a constant current in place of a constant potential (Figure 11.23). Controlled-current coulometry, also known as amperostatic coulometry or coulometric titrimetry, has two advantages over controlled-potential coulometry. First, using a constant current makes for a more rapid analysis since the current does not decrease over time. Thus, a typical analysis time for controlled-current coulometry is less than 10 min, as opposed to approximately 30-60 min for controlled-potential coulometry. Second, with a constant current the total charge is simply the product of current and time (equation 11.24). A method for integrating the current-time curve, therefore, is not necessary. 

Selecting the Voltammetric Technique The choice of which voltammetric technique to use depends on the sample s characteristics, including the analyte s expected concentration and the location of the sample. Amperometry is best suited for use as a detector in flow systems or as a selective sensor for the rapid analysis of a single analyte. The portability of amperometric sensors, which are similar to po-tentiometric sensors, make them ideal for field studies. 

The analytical research and development (R D) unit is often responsible for the preparation and vahdation of test methods. The R D lab is not faced with the same pressures for rapid analysis as the QC unit, where pending results often hold up production. In addition, R D often assigns personnel to specific instmments or techniques, whereas QC generally requires technicians to perform varied analyses. This leads to an expertise on the part of analytical chemists and technicians which is difficult to duphcate in QC. Therefore the R D test method should be mgged enough to withstand the different environment of the QC lab and stiU provide vahd results. 

Applications. Immunoassays are used in many different disciplines, having clinical, industrial, agricultural, and environmental appHcations. This technique has made possible rapid analysis of such varied analytes as vimses, toxins, hormones, foreign proteins, dmgs, and insecticides. 

In the early-to-marginal stages of subsynehronous vibration the phenomenon is highly intermittent, and requires the rapid analysis and high-resolution eapability of the real-time analyzer for its identifieation. 

Pentafluorobenzyl bromide has been used in the derivatization of mercaptans [55] and phenols [36], m the analysis of prostaglandins [37], and in quantitative GC-MS [5S] 1,3 Dichlorotetrafluoroacetone is used for the derivatization of amino acids to the corresponding cyclic oxazolidinones and allows the rapid analysis of all 20 protein ammo acids [d] Pentafluorophenyldialkylchlorosilane derivatives have facilitated the gas chromatographic analysis of a wide range of functionally substituted organic compounds, including steroids, alcohols, phenols, amines, carboxylic acids, and chlorohydrms [4]... 

H. Tani and M. Furuno, Rapid analysis of hydrocarbons and inert gases hy a multidimensional gas cltromatograph , J. High Resolut. Chromatogr. Chromatogr. Commun. 9 712-716(1985). 

G. P. Blanch, J. Villen and M. Heiraiz, Rapid analysis of free eiytlnodiol and uvaol in olive oils by coupled reversed phase liquid clnomatogi aphy-gas clnomatography , 7. Agric. Food Chem. 46 1027-1030 (1998). 

European countries, including the UK, and covers about 5% of the total European diesel market. It contains less than 5 vol%. of mono-ring aromatics and less than 0.1 vol%. of di- and higher-ring aromatics. Eurthermore it is low in sulfur. Both EC and SEC methods have been developed for the rapid analysis of aromatics in diesel fuel. 

Schnell-analyse, /. rapid analysis, -arbelts-stahl, m. high-speed steel, -aufldser, m. 

To allow all culture productiou to be coutrolled, a method for rapid analysis is required. Prior to development of an LC-MS method, the analysis was both complex and time-consuming, involving the purification of a relatively large amount of the antibody using affinity chromatography, enzymatic release, and subsequent derivatizafion of the oligosaccharides and their analysis by using capillary electrophoresis. 

Effective use of incomplete data sets Rapid analysis of data... 

In the wine industry, FTIR has become a useful technique for rapid analysis of industrial-grade glycerol adulteration, polymeric mannose, organic acids, and varietal authenticity. Urbano Cuadrado et al. (2005) studied the applicability of spectroscopic techniques in the near- and mid-infrared frequencies to determine multiple wine parameters alcoholic degree, volumic mass, total acidity, total polyphenol index, glycerol, and total sulfur dioxide in a much more efficient approach than standard and reference methods in terms of time, reagent, and operation errors. 

Gregory, G.K. et ah. Quantitative analysis of lutein esters in marigold flowers (Tagetes erecta) by high performance liquid chromatography, J. Food ScL, 51, 1093, 1986. Livingston, A.L., Rapid analysis of xanthophyll and carotene in dried plant materials, J. AOAC, 69, 1017, 1986. 

Livingston, A.L., Rapid analysis of xanthophyll and carotene in dried plant materials, J. AOAC, 69, 1017, 1986. 

The remarkable selectivity that is inherent in the reaction of an antibody with the antigen or hapten against which it was raised is the basis for the extensive use of immunoassay for the rapid analysis of samples in clinical chemistry. Immunochemical reactions offer a means by which the applicability of potentiometric techniques can be broadened. A number of strategies for incorporating immunoassay into the methodology of potentiometry have been explored... 

The application of 13C NMR for the rapid analysis of the oil composition of oil seeds is well known [16], 13C NMR has recently been applied to the quantitative analysis of the most abundant fatty acids in olive oil [17]. The values obtained by this method differed by only up to 5% compared with GLC analysis. The quantitative analysis was applied to the olefmic region of the high resolution 13C NMR spectrum of virgin olive oil to detect adulteration by other oils which differed significantly in their fatty acid composition. The application of the methodology for the detection of adulteration of olive oil by hazelnut oil is more challenging as both oils have similar chemical profiles and further experiments are in progress. 

Camilleri, P., Harland, G. B., and Okafo, G., High resolution and rapid analysis of branched oligosaccharides by capillary electrophoresis, Anal. Biochem., 230, 115,1995. 

LC-IR using surface-enhanced IR absorption spectroscopy (SEIRAS) was recently designed in order to develop a highly sensitive and rapid analysis method for polymer additives [506]. The method, which consists of spraying the LC eluents on to a metal film of Ag on a BaF2 substrate, allows an enhancement factor of about 90. 

Although liquid chromatography (l.c.) under elevated pressure is now used essentially for determining the molecular weight of heparin,74,75 as an alternative to methods using soft gels,76 it can undoubtedly be used as well for rapid analysis of mixtures of glycosaminoglycans. 

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