Chrom chromatography, chromatographic

Jones, K. Symposium on Advances in Chromatography (Chromatographic Society and Royal Society of Chemistry), Warrington, November 1986, reported in Chrom. Soc. Bull. 25 (1987) 23. Large-Scale HPLC. 

Ethylenethiourea (ETU) is a toxic decomposition product/metabolite of alky-lenebis(dithiocarbamates). This compound could be generated during processing of treated crops at elevated temperature. Different chromatographic methods to determine the residue levels of ETU have been published. After extraction with methanol, clean-up on a Gas-Chrom S/alumina column and derivatization (alkylation) with bro-mobutane, ETU residues can be determined by GC with a flame photometric detector in the sulfur mode. Alternatively, ETU residues can also be determined by an HPLC method with UV detection at 240 nm or by liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/tandem mass spectrometry (LC/MS/MS) (molecular ion m/z 103). ... 

Contents 1. Introduction 160 2. Methods to Achieve High-Resolution NMR Spectra in the Presence of Delaying Media 161 2.1. MAS for magnetic susceptibility averaging 161 2.2. Chrom-NMR without MAS 162 3. Mobility PFG 162 3.1. Diffusion NMR and its representation 162 3.2. Diffusion in multiphasic environments 164 3.3. Specificity of diffusion PFG measurements in porous media 165 4. Examples of Chrom-NMR 166 4.1. Comparison with Liquid Chromatography (LC) 166 4.2. Non-chromatographic mobile phases 169 5. Conclusions 171 Acknowledgements 172 References 172... 

Gas-liquid chromatography affords another technique by which the purity of the organotin hydrides may be ascertained. Tri-n-butyltin hydride, for example, may be chromatographed in a Pyrex column packed with Gas-Chrom Z solid support containing a 5% dispersion of silicone oil. 

Liquid Chromatography was performed on a Varian 8520 dual syringe pump liquid chromatograph. Two Vari-chrom variable wavelength detectors were used in series to provide a dual wavelength detection system. 

Lunn G, Schmuff NR (1997) HPLC Methods for Pharmaceutical Analysis. Wiley-Intersciences, New York Pan L, Ho Q, Tsutsui K et al. (2001) Comparison of chromatographic and spectroscopic methods used to rank compounds for aqueous solubility. I Pharm Sci 90(4) 521-529 PSOL (PION) http //www.pion-inc.com/pSOL.htm Silveston R, Kronberg B (1994) Accurate measurements of solubility and thermodynamic transfer quantities using reversed-phase liquid-liquid chromatography. I Chrom 659(l) 43-56... 

Procedure (See Chromatography, Appendix IIA.) Use a gas chromatograph equipped with a flame-ionization detector and a 4-m x 2-mm (id) stainless-steel column, or equivalent, packed with 15%, by weight, methyl trifluoropropyl silicone (DCFS 1265, or QF-1, or OV-210, or SP-2401) stationary phase on 80- to 100-mesh Gas Chrom R, or the equivalent. Condition a newly packed column at 120° and with a 30-mL/ min helium flow for at least 2 h (preferably overnight) before it is attached to the detector. For analysis, maintain the column isothermally at 105° the injection port and detector at 250° the carrier gas flow rate at 11 mL/min with fuel gas flows optimized for the gas chromatograph and detector in use. Change the experimental conditions as necessary for optimal resolution and sensitivity. The signal-to-noise ratio should be at least 10 1. 

Apparatus (See Chromatography, Appendix IIA.) Use a suitable gas chromatograph equipped with a 250-cm x 2-mm (id) glass column, or equivalent, packed with 3% OV-1 stationary phase on 100- to 120-mesh Gas Chrom Q, or equivalent, and with a flame ionization detector. Maintain the column at 175°, the injection port at 210°, and the detector at 230°. Relative retention times (min) D-anhydroglucoses (levoglucosan), pyranose form (3.7), furanose form (not present in standard) (4.3) n-octadecane (5.1) a-D-glucose (8.7) D-sorbitol (11.3) (3-D-glucose (13.3). 

Procedure (See Chromatography, Appendix IIA.) Use a suitable gas chromatograph equipped with a flame ionization detector (FID) and a 1.5-m x 4-mm (id) column packed with 3% OV-1 on 100- to 120-mesh diatomite CQ or 100- to 120-mesh Gas Chrom Q, or equivalent. Program the oven... 

Barker A. (1995) The chromatographic analysis of refined and synthetic waxes. In Chromatography in the Petroleum Industry J. Chrom. Lib. Ser. (ed. E. R. Adlard). Elsevier, Amsterdam, 56, 55-93. 

PCB materials in field-collected bald eagle specimens have been identified utilizing combined gas chromatography-mass spectrometry techniques in conjunction with thin-layer chromatographic separations of standard materials as well as tissue extracts (26). A total of 19 PCB compounds were detected in the field samples. Analyses were performed employing a spiral glass gas chromatographic column, 9 ft X 0.25 inch o.d., packed with 1% SE-30 on 100/120 mesh Gas Chrom Q. Mass spectra of the major components of Aroclor 1254 PCB standard were presented in this report as well as relative retention data for the individual components. 

Chrom. indicates the chromatographic method of choice GC, gas chromatography LC, liquid chromatography IC, ion chromatography. 

Figure 6-7 Separation of chromatographic peaks present in a 1 1 ratio as a function of resolution (iRJ. (From Snyder LR A rapid approach to selecting the best experimenta/ conditions for highspeed liquid column chromatography. Part I. Estimating initial sample resolution required by a given problem. J Chrom Sd 1972 10 202.)...

Martin used gas chromatonraphy to determine nicotine residues on mustard green samples. Samples of mustard green were analysed by the US official method, modified by the author for gas chromatography on a packed DC-200 column 10 % on Gas Chrom Q. The identity of the nicotine peak was confirmed by TLC after trapping the eluated compound from the gas chromatographic column. Recovery obtained on five samples spiked at the 1-3 ppm level ranoed from 95 to 97. ... 

Further, the use of selective ion monitoring in the gas chromatographic-mass spectrometric method greatly reduces the problem of biological interference as compared to electron-capture detection. The gas chromatography of the heptafluorobutyryl derivatives of scopoline was carried out either on a 6 feet by 2 mm I.D. glass column packed with 3 % OV-17 or 1 % OV-225 on Gas Chrom Q (200-120 mesh) at 95°C. 

Ebbighausen et al. developed a method for the assay of morphine and codeine in urine using deuterium labeled morphine and codeine. Codeine was derivatized with heptafluorobutyric acid and morphine with trifluoroacetic acid before gas chromatography on a packed column with 1 % 0V-17 on Gas Chrom Q. The LKB 9000 combination of gas chromatograph-mass spectrometer equipped with a multiple-ion detector/peak matcher was used. With a simple extraction procedure of 1 ml urine after hydrolysis a practical limit of detectability was found to be approximately 500 pg. 

Klein applied gas chromatography. 3-0-acetylmorphine results from an incomplete esterification of morphine with acetic anhydride and the amount may be of value for forensic purposes. Because of the very small amounts present in heroin, the compound was derivatized with hepta-fluorobutyric anhydride and gas chromatographed with a Ni electron capture detector on a 3 1 OV-17 on Gas Chrom Q packed column at 230°C using chlorpromazine as an internal standard. The heptafluorobutyric anhydride derivatives were extracted quantitatively from the reaction mixture with light petroleum and were stable for several hours in this solvent. However, it was recommended that upon formation, the analysis should be completed without delay. The analysis was carried out with 1-10 mg heroin samples and the amount of 3-0-acetylmorphine varied from 0.1 to 2 %, acetylcodeine from 3 to 15, morphine and codeine from 0.01 to 0.5. ... 

Elefant et al. were the first to use gas chromatography for the determination of theophylline in tablets that also contained other components (phenobarbital and ephedrine hydrochloride). One fine-ground tablet containing 130 mg theophylline was extracted with a chloroform-methanol (1 1) solution of the internal standard (4,4 -methylene-bis-(N,N-dimethylani-line) (0.6 mg/ml) and after centrifuging, the clear solution was injected into the gas chromatograph on a packed column with HI-EFF 8B 3 % on Gas Chrom Q at a column temperature of 250°C. Results of the assay are given in Table 20.7,... 

Gas chromatographic characteristics of several cyclopolymethylenetetrazoles and the conditions for their routine analyses by gas-liquid chromatography (GLC) have been determined <77MI 806-01 >. At a He flow rate of 60 ml min and oven temperature of 210°C on a 6 ft x in. stainless-steel tubing packed with 3% Hi-Eff 8-BP on 100/120 mesh Gas-Chrom Q, the retention time of pentamethylenetetrazole (PMT) is 210 s. With PMT as the standard, the retention time and sensitivity for (1) were found to be 0.99 and 0.16, respectively. The relatively low sensitivity for (1) was found to be due to decomposition at 210°C. By lowering the injection port temperature to 175°C, decomposition was reduced but not completely eliminated. ile the plot of average detector response time versus the concentration of tetrazoles was linear from 10 to 10 M, deviation from linearity was observed at concentrations greater than 10 M. 

Gas-Liquid Chromatographic Analysis Fluphenazine was not eluted after 90 minutes at 270°, using a 210 SE-30 silicone polymer on a 80-100 mesh Gas-chrom S diatomaceous earth column with a 3% SE-30 on 80-100 mesh Gas-chrom Q at 250°C, it eluted in 4.9 minutes. Fluphenazine was also well separated from other tranquilizers on a 120 mesh silanized Gas-chrom P column coated with 1% Hi-Eff-8B (cyclohexane-dimethanol succinate) at a temperature of 220°C and a retention time of 5 minutes. The identification of fluphenazine and other phenothiazine tranquilizers by gas chromatography of their pyrolysis products has also been reported. 

Fig. 8. Transformation of methyl litho-cholate by Raney nickel. Gas chromatography of products from the reaction as determined with a Hewlett-Packard Model 402 gas chromatograph fitted with a hydrogen flame detector and a silanized glass U-shaped column (6 ft x 1/4 in o.d.) filled with 3% OV-17 on 100-120 mesh Gas Chrom Q under these conditions flash heater, 280 C column, 260 C detector, 280°C helium, 40 psi at a flow rate of 80 cc/min (85).

Gorshkov. A. V. Much, H. Becker, H. Pasch, H. Evreinov, V. V. Entelis, S. G. Chromatographic investigations of macromolecules in the critical range of liquid chromatography. I. Functionality type and composition distribution in polyethylene oxide and polypropylene oxide copolymers. J. Chrom. 1990, 525, 91-102... 

Gas liquid chromatography. Analyses were carried out with a Hewlett Packard Model 5750 gas chromatograph equipped with a Flame Ionization Detector. For halogenated derivatives a Perkin Elmer Model F 30 gas chromatograph equipped with a %i electron capture detector was used. The column consisted of a glass tube (90 cm x 6 ram ID) packed with 100-120 mesh Gas-chrom Q (Applied Science Lab., State College, Pennsylvania, U.S.A.) coated with 3% U.C.W.98. 

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