Liquid reverse phase

OXIDATIVE LUMINESCENCE OF UV ABSORBING CHEMICALS. APPLICATION TO THEIR DETERMINATION IN SUNSCREEN PRODUCTS BY REVERSED PHASE LIQUID CHROMATOGRAPHY WITH CHEMILUMINESCENCE... 

J. E. MacNair, K. C. Lewis and J. W. Jorgenson, Ultraliigh-pressure reversed-phase liquid chromatography in packed capillaiy column . Anal. Chem. 69 983 (1997). 

K. Grob and Z. Li, Coupled reversed-phase liquid clir omatography-capillary gas clir O-matography for the determination of atr azine in water , J. Chromatogr. 473 423-430 (1989). 

K. Grob, Concurrent eluent evapor ation with co-solvent Capping for on-line reversed-phase liquid cliromatography-gas clir omatogr aphy. Optimization of conditions , J. Chromatogr. 477 73-86 (1989). 

T. Hyotylainen, K. Jauho and M-L. Riekkola, Analysis of pesticides in red wines by online coupled reversed phase liquid clir omatogr aphy with a vaporizer/precolumn solvent split/gas dischar ge interface , 7. Chromatogr. 813 113-119(1997). 

H. G. J. Mol, J. Staniewski, H.-G. Janssen and C. A. Cramers, Use of an open-tubular Capping column as phase-switching interface in on-line coupled reversed-phase liquid clir omatography-capillar y gas clir omatography , 7. Chromatogr. 630 201-212 (1993). 

T. Hyotylainen and M-L. Riekkola, Direct coupling of reversed-phase liquid cluomatog-raphy to gas cliiomatography , J. Chromatogr. 819 13-24 (1998). 

E. A. Hogendoom and P. van Zoonen, Coupled-column reversed-phase liquid cliro-matogr-aphy in envuonmental analysis , J. Chromatogr. 703 149-166 (1995). 

K. Benedek, S. Dong and B. E. Kaiger, Kinetics of unfolding of proteins on hydrophobic surfaces in reversed-phase liquid chiomatography , /. Chromatogr. 317 227-243 (1984). 

D. E. Martire and R. E. Boehm, A unified theory of retention and selectivity in liquid chromatography. 2. Reversed-phase liquid clrromatography with chemically bonded phases , J. Phys. Chem. 87 1045-1062 (1983). 

THREE-DIMENSIONAL SIZE EXCLUSION CHROMATOGRAPHY-REVERSE PHASE LIQUID CHROMATOGRAPHY-CAPILLARY ZONE ELECTROPHORESIS... 

Figure 9.10 Three-dimensional representation of the data volume of a tryptic digest of ovalbumin. Series of planar slices through the data volume produce stacks of disks in order to show peaks. Reprinted from Analytical Chemistry, 67, A. W. Moore Jr and J. W. Jorgenson, Comprehensive three-dimensional separation of peptides using size exclusion chromatogra-phy/reversed phase liquid chromatography/optically gated capillary zone electrophoresis, pp. 3456-3463, copyright 1995, with permission from the American Chemical Society.

F. J. Senorans, J. Tabera and M. Herraiz, Rapid separation of free sterols in edible oils by on-line coupled reversed phase liquid chr omatography-gas chromatography , 7. Agric. Food. Chem. 44 3189-3192 (1996). 

R J. Senorans, M. Heiraiz and J. Tabera, On-line reversed-phase liquid cliromatography using a programmed temperature vaporizer as interface , 7. High Resolut. Chromatogr. 18 433-437(1995). 

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). 

L. B. Nilsson, High sensitivity determination of the remoxipride hydroquinone metabolite NCQ-344 in plasma by coupled column reversed-phase liquid cliromatography and electi ochemical detection , Biomed. Chromatogr. 12 65-68 (1998). 

T. Okuda, Y. Nakagawa and M. Motohashi, Complete two-dimensional separation for analysis of acidic compounds in plasma using column-switching reversed-phase liquid clrromatography , 7. Chromatogr. B126 225-236 (1999). 

H. M. M. Arafa, E. M. A. Hamada, M. M. A. Elzamai and H. Nau, Eully automated detemination of selective retinoic acid receptor ligands in mouse plasma and tissue by reversed-phase liquid chi omatography coupled on-line with solid-phase extraction , 7. Chromatogr. A 729 125-136 (1996). 

E. C. Goosens, D. de Jong, G. J. de Jong and U. A. Th Brinkman, Reversed-phase liquid cliromatography coupled on-line with capillary gas chromatography. II. Use of a solvent vapor exit to ina ease introduction volumes and introduction rates into the gas cliromato-graplT, J. Microcolumn Sep 6 207-215 (1994). 

T. Hyotylainen, H. Keski-Hynnila and M. E. Riekkola, Determination of moipliine and its analogues in urine by on-line coupled reversed-phase liquid cliromatography-gas cliromatography with on-line derivatization , 7. Chromatogr. A 771 360-365 (1997). 

A. W. Moore-Jr and J. W. Jorgenson, Comprehensive tliree-dimensional separation of peptides using size exclusion chromatography/reversed phase liquid cliromatography/ optically gated capillary zone electrophoresis . Awn/. Chem. 67 3456-3463 (1995). 

When environmental samples are analysed by reverse-phase liquid ehromatogra-phy, the most widely used teehnique, polar interferenees usually appear (ions, plus humie and fulvie aeids). This makes it diffieult to determine more polar eompounds that elute in the first part of the ehromatogram. This is speeially important when deteetion is not seleetive, e.g. UV deteetion, whieh is one of the most eommon teeh-niques in routine analysis. In sueh eases, multidimensional ehromatography plays an important role. 

Figure 13.5 Schematic presentation of the procedure involved in coupled-column RPLC AS, autosampler C-1 and C-2, first and second separation columns, respectively M-1 and M-2, mobile phases S-1 and S2, interferences A, target analytes HV, high-pressure valve D, detector. Reprinted from Journal of Chromatography, A 703, E. A. Hogendoom and R van Zoonen, Coupled-column reversed-phase liquid cliromatography in environmental analysis , pp. 149-166, copyright 1995, with permission from Elsevier Science.

Figure 13.7 Selectivity effected by employing different step gradients in the coupled-column RPLC analysis of a surface water containing 0.40 p-g 1 bentazone, by using direct sample injection (2.00 ml). Clean-up volumes, (a), (c) and (d) 4.65 ml of M-1, and (b) 3.75 ml of M-1 transfer volumes, (a), (c) and (d), 0.50 ml of M-1, and (b), 0.40 ml of M-1. The displayed cliromatograms start after clean-up on the first column. Reprinted from Journal of Chromatography, A 644, E. A. Hogendoom et al, Coupled-column reversed-phase liquid chromatography-UV analyser for the determination of polar pesticides in water , pp. 307-314, copyright 1993, with permission from Elsevier Science.

Figure 13,12 Illusti ation of the clean-up method, showing the analysis of an air sample (a) with and (b) without column switching. Details of the analytical conditions are given in the text. Reprinted from Journal of Chromatography, A 697, R R. Kootsti a and H. A. Herbold, Automated solid-phase exti action and coupled-column reversed-phase liquid cltromatogra-phy for the trace-level determination of low-molecular-mass carbonyl compounds in ak , pp. 203-211, copyright 1995, with permission from Elsevier Science.

Figure 13.13 On-line trace eniicliment-RPLC-diode-aiTay detection (DAD) cliromatogram (at 230 nm) obtained from 200 ml of tap water spiked with various pesticides at levels of 1 p.g L. Reprinted from Chromatographia, 43, C. Aguilar et al., Deteimination of pesticides by on-line ti ace emicliment-reversed-phase liquid clrromatography-diode-aiTay detection and confirmation by paiticle-beam mass specti ometi y , pp. 592-598, 1996, with permission from Vieweg Publisliing.

However, for water analysis, reverse-phase liquid chromatography is more suitable but its coupling with GC has some drawbacks because of the partly aqueous effluent. Several systems have been developed (88, 89) and applied to determine pollutants in water. 

One of the first examples of the application of reverse-phase liquid chromatography-gas chromatography for this type of analysis was applied to atrazine (98). This method used a loop-type interface. The mobile phase was the most important parameter because retention in the LC column must be sufficient (there must be a high percentage of water), although a low percentage of water is only possible when the loop-type interface is used to transfer the LC fraction. The authors solved this problem by using methanol/water (60 40) with 5% 1-propanol and a precolumn. The experimental conditions employed are shown in Table 13.2. 

E. A. Hogendoorn, U. A. Brinkman, Th and R van Zoonen, Coupled-column reversed-phase liquid-chr omatography-UV analyser for the determination of polar pesticides in water , ]. Chromatogr. 644 307-314 (1993). 

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