LiChrosorb Diol

Liquid chromatography cleanup on a LiChrosorb Diol column has been further proposed for the offline purification of chloramphenicol residues from bovine muscle and eggs (32). An online approach based on reversed-phase principles has also been described for isolation of chloramphenicol residues from swine kidney by an automated column switching system (63). Use of a protein exclusion column (Hisep) has been also suggested in an online trace-enrichment method for the determination of chloramphenicol in animal tissues (52). By employing a column-switching system, all chloramphenicol that eluted from the protein exclusion column was trapped at the entry of a 5 m Supelcosil LC-18 preconcentration column, to be subsequently back-flashed into the analytical column. 

Margarine, infant for- Saponify (hot), extract LiChrosorb Diol 5 pm Hexane/MTBE, 14 + 6 a-, / -, y-, (5-T Fluorescence ... 

Figure 3. Plot of the log of the retention time vs. solvent strength measured with Nile Red for 5 phenols at 50° and 138 bar (outlet). The percent methanol in carbon dioxide is indicated at top of figure. Column 4.6 x 200 mm, 5 /im Lichrosorb Diol. Flow 2.5 ml/min.

Diol-substituted siliccf LiChrosorb DIOL Nucleosil 7 OH ... 

Hyoscyamine can be determined by fluorimetric technique as follows (100). A solution of hyoscyamine or an eluate of it from a LiChrosorb DIOL HPLC column is treated with 9,10-dimethoxy anthracene-2-sulfonate solution. The resulting derivative is determined fluorimetrically at 446 nm with excitation at 383 nm. 

Column Lichrosorb Diol 10 pm (150x3.2 mm ID) loaded with 0.1 M naphtalene-2-sulfonate in 0.1 M aqueous phosphate buffer (pH 2.1) by subsequently pumping 30 ml of phosphate buffer (pH 2.1) and 50 ml of the stationary phase through the column, followed by the mobile phase until no more droplets could be observed in the eluate (ca. 20 ml). Finally the column was recycled with 500 ml of mobile phase. Mobile phase chloroform - n-propanol (9 1) and chloroform - n-propanol (9 1) saturated with the stationary phase mixecf in a ratio (1 9), flow rate 0.1> ml/min, detection UV 254 nm. Peaks 1, tetrabutylammonium 2, tributylmethylammonium 3, tetrapropylanmonium 4, tripropylmethylanmonium. (reproduced with permission from ref. 21, by the courtesy of Acta Pharmaceutica Suecica). 

Lichrosorb DIOL 10 ym 150x3.2 CHCl,-prOH(9 l) sat. with the statio- ... 

For the separation of fullerenes by HPLC the stainless steel columns with Alusorb N 200, li Bondapak 10 CIS, LiChrosorb Diol, LiChrosorb SI 60 with bonded diphenylsilyl groups were used [16]. For the semi-preparative separation of Ceo and C70 glass column (70x12 mm) packed by LiChrosorb SI 60 with deposited carbon layer prepared by modified method [15] was used [16]. 

The most convenient column for the separation of fullerenes and their oxides is the column packed by LiChrosorb Diol with eluent containing n-hexane and n-pentane. This... 

Analytical and preparative separation of proteins soluble in an organic phase (n-propanol) has been carried out on a LiChrosorb-Diol column. This type of chromatography has been termed normal phase (R8). It has been applied to the analysis of proteins in dialyzed fetal calf serum (R8) and in the separation of protected hydrophobic oligopeptides (Nl), but as yet, it has not been used in a clinical chemical application. 

It is important to select column switching times carefully in order to produce an effective sample cleanup. The selection was made by characterizing the Lichrosorb-DIOL precolumn and conducting a switching time survey. As a general guide to the column switching time selection procedure, we describe next in some detail the methods we used for this assay. The details of course will vary from system to system. 

The precolumn was first characterized by evaluating the retention times of NADH and the known electrochemical interferences. Spectroscopic detection was used for this, since the electrode passivators (IgG, HSA), uric acid, and NADH absorb at 280 nm, and IgG and HSA are electroinactive at 750 mV versus Ag/AgCI. Figure 16 shows a chromatogram of a blank human serum—NADH mixture which was injected into the Lichrosorb-DIOL precolumn. The first peak (retention time of 113 sec) was primarily composed of IgG and HSA. The second peak (173 sec) was NADH the shoulder that appears at approximately 190 sec was uric acid. Therefore a heart-cut should be from 150 sec (to remove the macro-molecular fraction) to 185 sec (to remove the late-eluting uric acid among other possible interferences). 

Fig. 16. Chromatogram of blank human serum calibrator-NADH mixture. Lichrosorb-DIOL column, flow rate 1.1 ml/min, detection by absorbance at 280 nm (A) HSA and IgG, (B) NADH, and (C) uric acid.

Column 300 x 0.32 5 p-m LiChrosorb Diol Mobile phase Carbon dioxide MeOH 91.5 8.5 Column temperature 80 Iiljection volume 0.2 Detector UV 254... 

Fig. 11.2.3. HPLC of leucocyte interferon. Chromatographic conditions column, Lichrosorb Diol (250x4.6 mm I.D.) mobile phase, 80% n-propanol/0.1 N sodium acetate, pH 7.5, elution was achieved with a linear gradient of decreasing propanol concentration as shown flow rate, 0.25 ml/min temperature, ambient detection, post-column fluorescence using fluram. Reproduced from Rubinstein et al. (1980), with...

In this method the sample is applied to the column in a less polar solvent and eluted with a gradient of increasing polarity. Different species of human leukocyte interferon were separated on a Lichrosorb diol column with a gradient of decreasing n-propanol concentration (Rubinstein et a/., 1979). The Lichrosorb NH2 column has been used in the normal-phase mode for resolving amino acid mixtures (Schuster, 1980). 

Solute and ionic strength TSKgel G3000SW LiChrosorb Diol SynChropak GPC 100 TSKgel G2000SW Waters I-... 

Figure 6. Resolution of camphorsulfbnic add [24]. Stationary phase LiChrosorb DIOL S system peak. Mobile...

Hackzell and co-workers utilized dimethylprotripty-line, a tricyclic quaternary ammonium ion, in the stationary aqueous phase for detection of carboxylates and alkylsulfonates [16], The response was dependent on the retention, which indicated adsorption of the ion-pairs to the solid phase, in this case LiChrosorb DIOL. 

Figure 2.5 Supercritical fluid chromatogram, with use of a miniaturized evaporative lightscattering detector, of an extract obtained from oat bran. Column 100 nun x 0.9 mm, packed with LiChrosorb Diol, 5 pm. Conditions temperature 22°C pressure 300 atm. Mobile phase carbon dioxide modified with 19 mol% methanol. Restrictor 45 mm x 9 pm at 90°C. Peaks TG = triacylglycerols MGDG = monogalactosyldiacylglycerols PC = phosphatidylcholines DGDG = digalactosyldiacylglycerols.

Cyanopropyl bonded packing has been described as suitable for the separations of human type I-III collagens. Other stationary phases should also be mentioned LiChrosorb Diol, TSK-SW gels and Separon HEMA 1000 Glc (a copolymer of 2-hydroxyethyl methacrylate and ethylene dimethacrylate covalently bonded with glucose). The first two phases are widely used for the separation of a number of proteins, but the use of the last phase (HEMA) is mainly used for the separation of collagens. The elution is performed by isocratic conditions with 0.2 M NaCl-2 M urea-0.05 M Tris/HCl (pH 7.5) as the mobile phase. This enabled the separation of a-, 3-, and y-chains... 

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