Silver-ion liquid chromatography

While silver ion liquid chromatography has been utilized to separate fatty acid methyl esters (FAMEs) by number of double bonds and by the configuration (cis/trans) of the double bonds [1-3], the lack of commercial HPLC silver ion columns has limited the impact of this technology. 

Ratnayake, W.M.N. Overview of Methods for the Determination of Trans Fatty Acids by Gas Chromatography, Silver-Ion Thin-Layer Chromatography, Silver-Ion Liquid Chromatography, and Gas Chromatography/Mass Spectrometry. J. AOAC International 87-. 523-539 (2004). 

Mossoba, M.E.R. Dugan, and J.K.G. Kramer. Methods for Analysis of Conjugated Linoleic Acids and trans- %-. Isomers in Dairy Fats by Using a Combination of Gas Chromatography, Silver-Ion Thin-layer Chromatography/Gas Chromatography, and Silver-Ion Liquid Chromatography, ]. AOAClnt.. 87, 545—562 (2004). 

Sun, C., Black, B.A., Zhao, Y.Y., Ganzle, M.G. and Curtis, J.M. (2013) Identification of conjugated linoleic acid (CLA) isomers by silver ion-liquid chromatography/in-line ozonolysis/mass spectrometry (Ag LC/03-MS). Anal. Chem. 85, 7345-7352. 

Buchgraber, M. and Ulberth, F. 2001. Determination of trans octadecenoic acids by silver-ion chromatography-gas liquid chromatography An intercomparison of methods. AOAC International 84 1490-1498. 

Fig. 30 Silver ion high-performance liquid chromatography (Ag-HPLC-FID) with flame ionization detector (FID) analysis of the triacylglycerols of chromatographed Crepis alpina seed oil. Ag-HPLC-FID conditions 0.5-mg sample 5-micron Chromspher Lipids column (Chrompack International, Middelburg, The Netherlands) (4.6 X 250 mm) mobile phase 0.5% acetonitrile in hexane (v/v) flow rate 1.0 ml/min FID. Chromatogram peak triacylglycerol fatty acid abbreviations S, saturated (palmitic and stearic) O, oleic L, linoleic and Cr, crepenynoic fatty acids.

Christie, W.W. (1995) Silver ion high-performance liquid chromatography, in New Trends in Lipid and Lipoprotein Analysis (eds J.-L. Sebedio and E.G. Perkins), AOAC Press, Champaign, Illinois, USA, pp. 59-74. 

Rickert, R., Steinhart, H., Fritsche, J., Sehat, N., Yurawecz, M.P., Mossoba, M.M., Roach, J.A.G., Eulitz, K., Ku, Y., Kramer, J.K.G. 1999. Enhanced resolution of conjugated linoleic acid isomers by tandem-column silver-ion high performance liquid chromatography. J. High Resol. Chromatogr. 22, 144—148. 

O. R. Adlof, Normal-phase separation effects with lipids on a silver ion high-performance liquid chromatography column,/. Chromatogr. A 764 (1997),337-340. 

The stability constants of silver ion complexes have been evaluated by classical partition techniques (130,131) and more recently by the measurement of dissociation pressures (132,133) and the methods of gas-solid (134) and gas-liquid chromatography (135,136). The use of supported solutions of silver nitrate as a stationary phase for the separation of olefins is now quite general. Enthalpies of formation have been recorded for olefin complexes of silver borofluoride (132), for silver nitrate complexes with cyclic olefins (131) and for silver nitrate-butadiene complexes (133) the results are summarized, together with some values for the ethylene-silver ion complex, in Table XXXVIII. 

Laakso P, Voutilainen P. Analysis of triacylglycerols by silver-ion high-performance liquid chromatography-atmospheric pressure chemical ionization spectrometry. Lipids 1996 31 1311-22. 

Santinelli, F., Damiani, R and Christie, W.W. (1992) The triacylglycerol structure of olive oil determined by silver ion high performance liquid chromatography in combination with stereospecific analysis. J. Am. Oil Chem. Soc., 69, 552-557. 

Neff, W.E., Adlof, R.O., List, G.R. and El-Agaimy, M. (1994) Analysis of vegetable oil triacylglycerols by silver ion high performance liquid chromatography with flame ionization detection. J. Liq. 

Silver ion chromatography is used primarily in liquid [213,215-218], thin-layer [212,213,216,219], and supercritical fluid chromatography [220-222] for the separation of fatty acid derivatives and triacylglycerols, and to a lesser extent, terpenes, sterols, carotenoids, and pheromones. Silver ion chromatography is widely used on its own, or as a preliminary simplification step, to elucidate the stmctures of fats, oils and lipids [213]. It is possible to fractionate animal or fish oils into fractions with zero to six double bonds. Species with the same total number of double bonds can be separated based on the difference in the number of double bonds in individual acyl residues. 

Urinary iodide was measured using paired-ion reversed-phase high-performance liquid chromatography (HPLC) with electrochemical detection employing a silver working electrode (Rendl etal., 1994). A detection limit of 5 pg was achieved. 

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