Chromatography identification using

Sz. Nyiredy, Zs. Fater and B. Szabady, Identification in planar chromatography by use of retention data measured using characterized mobile phases , ]. Planar Chromatogr. 7 406-409 (1994). 

Identification Using High Performance Liquid Chromatography... 

Kuronen, P., Identification using retention indices on gradient HPLC, in Retention and Selectivity in Liquid Chromatography, Smith, R. M., Ed., Elsevier Science, Amsterdam, 1995, chap. 6. 

Bay, Massachusetts. Gas liquid chromatography was used to detect hydrocarbons present at different depths in the sediment, while low resolution mass spectrometry was employed to measure concentrations of paraffins, cycloparaffins, aromatics and polynuclear aromatics. Their data show that the concentrations of total and saturated hydrocarbons decreased with increased depth, and it was noted that identification and quantification of hydrocarbons in oil-contaminated sediments is required if the fate of these compounds in dredge spills is to be determined. 

Analytical methods exist for measuring heptachlor, heptachlor epoxide, and/or their metabolites in various tissues (including adipose tissue), blood, human milk, urine, and feces. The common method used is gas chromatography (GC) coupled with electron capture detection (ECD) followed by identification using GC/mass spectrometry (MS). Since evidence indicates that heptachlor is metabolized to heptachlor epoxide in mammals, exposure to heptachlor is usually measured by determining levels of heptachlor epoxide in biological media. A summary of the detection methods used for various biological media is presented in Table 6-1. 

Capillary gas chromatography (GC) using modified cyclodextrins as chiral stationary phases is the preferred method for the separation of volatile enantiomers. Fused-silica capillary columns coated with several alkyl or aryl a-cyclo-dextrin, -cyclodextrin and y-cyclodextrin derivatives are suitable to separate most of the volatile chiral compounds. Multidimensional GC (MDGC)-mass spectrometry (MS) allows the separation of essential oil components on an achiral normal phase column and through heart-cutting techniques, the separated components are led to a chiral column for enantiomeric separation. The mass detector ensures the correct identification of the separated components [73]. Preparative chiral GC is suitable for the isolation of enantiomers [5, 73]. 

Mass chromatography is a new form of gas chromatography that uses two gas density detectors operated in parallel and provides (a) mass of components within 1-2% relative without determination of response factors, (b) molecular weight of components within 0.25-1% in the mass range 2—400, and (c) a powerful identification tool by the combined use of retention time and molecular weight data. The theoretical basis of the technique and its scope as a molecular weight analyzer, a qualitative identification tool, and a quantitative analyzer in the polymer field are discussed. 

RE Buehler, MB McDonald Jr, TT Van Toai, SK St Martin. Soybean cultivar identification using high performance liquid chromatography of seed proteins. Crop Sci 29 32-37, 1989. 

Gas chromatography was used to determine n-paraffin distribution in the oil and wax samples. An F and M Instrument Company Model 500 chromatograph was used with an uncompensated single column, a helium carrier gas flow rate of 25 ml/min., and a thermal conductivity detector. The column was 4.8 mm in diameter and 3.3 m in length, and was packed with 3% Dexil 300 on Chromo-sorb P. The block and injection port temperatures were maintained at 673 K. The column was temperature-programmed from 348 K to 673 K at a rate of 5.7 K per minute. Peak identification was aided by the use of internal standards of decane, dodecane, and hexadecane. The baseline was determined by heating without sample injection. Response values were not available for the various areas on the traces, so the analyses were reported as % by area. 

Gu, M., Wang, Y., Zhao, X. G., and Gu, Z. M. (2006). Accurate mass filtering of ion chromatograms for metabolite identification using a unit mass resolution liquid chromatography/ mass spectrometry system. Rapid Commun. Mass Spectrom. 20 764-770. 

Hop, C. E., Tiller, P. R., and Romanyshyn, L. (2002). In vitro metabolite identification using fast gradient high performance liquid chromatography combined with tandem mass spectrometry. Rapid Commun. Mass Spectrom. 16 212-219. 

Li, A. C., Gohdes, M. A., and Shou, W. Z. (2007). N-in-one strategy for metabolite identification using a liquid chromatography/hybrid triple quadrupole linear ion trap instrument using multiple dependent product ion scans triggered with full mass scan. Rapid Commun. Mass Spectrom. 21 1421-1430. 

Wrona, M., Timo, M., Bateman, K. P., Mortishire-Smith, R. J., and O Connor, D. (2005). All-in-one analysis for metabolite identification using liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry with collision energy switching. Rapid... 

R. B. Gaines, G. S. Frysinger, M. S. Hendrick-Smith and J. D. Stuart, Oil spill source identification using comprehensive two-dimensional gas chromatography , Environ. Sci. Technol. 33 2106-12 (1999). 

Examples illustrating the use of PCA for identification and classification are given in Chapter 9, including classification of American Indian obsidian artifacts by trace element analysis, identification of fuel spills by gas chromatography, identification of recyclable plastics by Raman spectroscopy, and classification of bees by gas chromatography of wax samples. 

Dear GJ, Plumb RS, Sweatman BC et al. (2000) Mass directed peak selection, an efficient method of drug metabolite identification using directly coupled liquid chromatography-mass spectrometry-nuclear magnetic resonance spectroscopy. J Chromatogr B Biomed Sci Appl 748 281-293... 

Yates JR, Carmack E, Hays L, Link AJ, Eng JK (1999) Automated protein identification using microcolumn liquid chromatography-tandem mass spectrometry. Methods Mol Biol 112 553-569... 

Paper chromatography Has largely been superseded by more sophisticated chromatographic methods in bioanalytical laboratories however this method still remains an important teaching tool to illustrate basic chromatography principles and technique. It still retains value in sample identification using appropriate standards (controls), for example in amino acid analysis. 

Slow exchange may lead to extremely broad polydispersities and often to polymodal MWDs. It is recommended to study the evolution of molecular weights with conversion and especially the proportion and position of various peaks in the MWD by size-exclusion chromatography (SEC). Use of scavengers is helpful in the identification of the origin of peaks in SEC (MWD) traces. For example, salts with common ions suppress free ions and reduce the intensity of peaks formed by free ions. Hindered pyridines trap protons and reduce peaks resulting from protonic initiation, especially in systems with adventitious moisture. Apparently, stability of complex anions MtX +, and MtX OH can be different and slow exchange may lead to polymodal MWD. 

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