Isopropanol-OD

Deuterium oxide (7.5 ml) is added dropwise to aluminum isopropoxide (25 g.) The mixture is shaken for about 5 min and then warmed to 70° for 10 min to complete the reaction. The resulting deuterioisopropanol is distilled at room temperature and 1 mm pressure into a liquid nitrogen-cooled trap. Redistillation at atmospheric pressure yields pure isopropanol-OD (9.5 g bp 82-83°). All operations must be protected from moisture. 

Tri-isopropyl borate (94 g) is placed into a 250 ml round bottom flask (oven dried) and deuterium oxide (30 ml) is added with stirring. Boric acid begins to precipitate immediately. There action mixture is stirred and heated under 

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Let us now discuss some of the characteristics of this quenching with mercaptans and disulfides. Interestingly, both sulfur derivatives are equally effective in inhibiting the photoreduction and are in fact interconverted during the reaction. The same equilibrium mixture of mercaptan and disulfide is obtained regardless of which was initially added to the reaction mixture. Furthermore, there appears to be no appreciable consumption of the sulfur compounds/64 When benzophenone is irradiated in the presence of isopropanol (OD) and mercaptan, isopropanol containing two deuterium atoms is isolated,... 

Isoallospirostane-3,l l,dione, 136 Isomerization of olefins, 360 Isopropanol-OD, 213 17a,21-Isopropylidenedioxypregn-4-ene-... 

Samples dissolved in methanol, diluted in water and injected in Spherisorb ODS-2 colunm, elution with water/acetonitrile (7 3) containing 5 mM octylamineZ-phosphoric acid at pH 6.4 Separation on STR ODS-II colunms and gradient elution with 20 mM anunonium phosphate buffer (pH 6.8)/isopropanol (25 1 v v) and acetonitrile) at 40°C... 

In another study, the authors reported a comparative study of the enantiomeric resolution of miconazole and the other two chiral drugs by high performance liquid chromatography on various cellulose chiral columns in the normal phase mode [79], The chiral resolution of the three drugs on the columns containing different cellulose derivatives namely Chiralcel OD, OJ, OB, OK, OC, and OE in normal phase mode was described. The mobile phase used was hexane-isopropanol-diethylamine (425 74 1). The flow rates of the mobile phase used were 0.5, 1, and 1.5 mL/min. The values of the separation factor (a) of the resolved enantiomers of econazole, miconazole, and sulconazole on chiral phases were ranged from 1.07 to 2.5 while the values of resolution factors (Rs) varied from 0.17 to 3.9. The chiral recognition mechanisms between the analytes and the chiral selectors are discussed. 

The effect of temperature on the RP-HPLC behaviour of /(-carotene isomers has been extensively investigated and the results were employed for the separation of carotenoids of tomato juice extract. Carotenoids were extracted from food samples of 2g by adding magnesium carbonate to the sample and then extracted with methanol-THF (1 1, v/v) in a homogenizer for 5min. The extraction step was repeated twice. The collected supernatants were evaporated to dryness (30°C) and redissolved in methanol-THF (1 1, v/v). Separations were performed on a polymeric ODS column (250 X 4.6 mm i.d. particle size 5/.an). The isocratic mobile phase consisted of methanol-ACN-isopropanol (54 44 2, m/m). The flow-rate was 0.8 or 2.0 ml/min. The effect of temperature on the retention times of lycopene and four /(-carotene isomers is shown in Table 2.11. The data indicated that the temperature exerts a considerable influence on the retention time and separation of /(-carotene isomers. Low temperature enhances the efficacy of separation. 

Product ester ee was determined by isocratic normal-phase high-performance liquid chromatography using a Chiralcel OD-H (250 mm x 4.6 mm) column and a 98 % hexanes/2 % isopropanol mobile phase at 1.75 mL min and 25 °C. The undesired (/ )-ester and desired (5)-ester were quantified using their characteristic retention times of 10.3 min and 21 min respectively during elution. 

HPLC methods can be ntilized for the pre-concentration of aromatic amines from polluted waters on silica gel or octadecyl silica (ODS) colnmns [55], The determination is then performed by RP HPLC using ODS packings as the stationary phases and a mixture of methanol, isopropanol, and water as the mobile phase [55], RP HPLC with diode array detector (DAD) methods coupled on-line with a continnons seqnential anaerobic/aerobic reactor system have been employed in wastewaters treatments [56], A continnons monitoring of the possible presence of aromatic amines in azo dyes wastes is based on indncing in the waste, the reaction of a reduction of the dye, followed by HPLC/ UV or HPLC/MS analysis [57-59], The redncing agent solutions are sodium dithionite or tin(II) chloride in an aqneons acidic medinm at 70°C, followed by SPE [58,59], LLE [60,61], or SEE [60-62],... 

The concentrations of benzaldehyde, the mixed product, and benzoin and the enantiomeric excesses (revalues) were determined by chiral-phase HPLC with a photodiode array detector. Chiral-phase HPLC was performed on a Chiracel OD-H (Daicel, Diisseldorf, Germany) using isohexane/isopropanol (90 10) as eluent, a flow rate of 0.5 mL min and a column oven at 40 °C. The retention time for benzaldehyde was 10.2 min, for the mixed product DMA-HPP 15.1 and 16.4 min, for the (S)-benzoin 20.3 min, and for the (R)-benzoin 28.5 min. 

The crude mixture was monitored by chiral stationary phase (CSP) HPLC (eluent hexane/isopropanol 95/5, 0.5mLmin, Chiralcel OD-H). After 2 h, (i/f,25)-l-phenyl-3,4-dihydronaphthalene oxide (80% ee) was obtained as the major enantiomer (fR=13.9 min) with 100% conversion (calculated using the internal standard) the minor 1S,2R) enantiomer eluting first (rR=10.1 min). 

After the screening of different chiral stationary phases and modifiers (for a review of screening methods please refer to the work of Wewers [29]), the best separation conditions were obtained using the chiral stationary phase (CSP) Chi-ralcel OD 20pm. An organic modifier, isopropanol (IPA), was used to increase the polarity of the eluent in order to get an acceptable retention of the two enantiomers. 

The advances in column and instrument technology have significantly enhanced HPLC performance in recent years. Results comparing the effects of various column packings on TG separation by RP-HPLC were presented by El-Hamdy and Perkins (87). Six commercially packed columns produced by different manufacturers were used PARTISIL ODS-1 and ODS-2 octadecyl-bonded silica of 10-/rm partical size, ZORBAK-ODS octadecyl-silica of 6-7-/rm diameter (250 X 4.6-mm ID), 5-/rm octyl-bonded spherical silica LC-8, 5-//m methyl-bonded spherical silica LC-1, and a 5-/rm octadecyl-bonded spherical silica LC-18 (150 X 4.6-mm ID). The mobile phase employed consisted of mixtures of methanol/acetone/isopropanol/acetonitrile ranging from l 0 3 4to 1 6 3 4. Triglycerides were solubilized in either THF or acetone at 100 mg/ml for each compound. 

Determine the enantiomeric excess by chiral HPLC analysis Chiracel OD, heptane isopropanol, 90 10 flow 0.6 ml/min retention time 12.6 (major) and 15.3 (minor enantiomer) min. 

Mixtures of benzodiazepines and thiazide diuretic drugs were separated by gradient elution CEC and identified using ESI-MS by Taylor and Teale [38], They used 330-500 x 50-75 pm i.d. colums packed with Hypersil ODS and Apex ODS and gradients of 50-80% acetonitrile in 5 mmol/1 aqueous ammonium acetate to elute the sample components. Benzodiazepines were detected in the positive ion mode using 1% acetic acid as the sheath liquid, whereas the thiazide diuretics were detected in the negative ion mode with 80% isopropanol in water as sheath liquid. 

Separation of triglycerides is amenable to capillary electrochromatography using a 3 pm Hypersil ODS-packed column with acetonitrile-isopropanol-w-hexane (57 38 5 v/v/v) as mobile phase. With a 20- or 40 cm x 100 pm i.d. column the result seen in Fig. 10.13 can be obtained at 30 kV and 20°C [52]. The retention parameters were quite acceptable, as demonstrated by RSD of the individual analytes present. The same approach is recommendable for analysing a formulation consisting of some... 

Triglycerides in pharmaceutical formulation including testosterone phenyl propionate, testosterone propionate, testosterone isocaproate, testosterone decanoate Hypersil ODS, 3 pm Acetonitrile-isopropanol-n-hexane (57 38 5) 50 mM ammonium acetate 250 mm x 100 pm i.d. 52... 

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