Zorbax SIL

A flame-dried flask under argon containing a 0.08 M THF solution of 317 mg (1.0 mmol) of the 2-(l- or 2-naphthyl)-substituted 4,5-dihydrooxazole is cooled to a temperature of between — 80 and 0 CC (see ref 7) and is treated with 1.5-2.0 equiv of the alkyllithium. The solution becomes deep red over 2-4 h and is quenched by the dropwise addition of 1.5 equiv of the electrophile (either neat or as a THF solution). The temperature is maintained for 1 h and then the solution is warmed gradually to 0 JC. The solution is diluted with 100 mL of diethyl ether and washed with 5 mL of sat. NH4C1, followed by 3 mL of sat. aq NaCI. The combined aqueous layers are back-extracted with 10 mL of CII2C12, and the combined extracts are dried over Na2S04. Concentration of the filtrate in vacuo provides a yellow oil, which is flash chromatographed over silica gel (1 -10% ethyl acetate in hexane) to yield the desired adducts. The diastereomeric ratios are determined by HPLC (Zorbax Sil column, Du Pont). 

System (4) has been described for the analysis of corticosteroids in human adrenal tissues [152]. Prior to the HPLC analysis, the corticosteroids were extracted from adrenal tissues by acetone. The permissible columns were 20 cm X 2.4 mm, consisting of Zorbax-SIL (for more polar compounds) or Zorbax-CN (for less polar compounds). The mobile phase was 9 4 1 cyclohexane-dichloromethane-ethanol or aqueous methanol, and eluted at a flow rate of 0.4 mL/min. Using a UV detection wavelength of 254 nm, sample recoveries were 78.5-99.5%, and the relative standard deviation was 2-5%. 

Supercritical fluid chromatography (SFC) has also been used in phospholipid analysis. According to Lafosse et al., phospholipid classes can be separated by SFC using a simple isocratic solvent consisting of 78.4/21.6 (w/w) mixture of carbon dioxide and a mixture of methanol, water, and triethylamine (95/4.95/0.05) in combination with a Zorbax Sil stationary phase detection was performed by evaporative light-scattering (20). 

Detection, is by UV at 228 nm and a Zorbax Sil Column, 4.6 mm x 25 can (DuPont Instruments, Wilmington, DE) equipped with a Whatman HC Pellosil precolumn (Whatman Inc., Clifton, NJ) is used. An apparent pH of 10.5 has been used, and according to the authors column performance was satisfactory for more than a five months period in spite of the high alkalinity. 

Normal-phase columns, either Water s jx Porasil or DuPont s Zorbax-sil , were used for the data of Sheridan s... 

The product was separated from the substrate on a normal phase silica gel column (Zorbax Sil) and eluted with methanol at 35°C as shown in Figure 9.621,II. The concentration of the reactants was determined by the fluorescence intensity at 535 nm, with an excitation wavelength at 340 nm. 

Separation was carried out by normal phase HPLC on a Zorbax Sil column with a solvent of 10% 2-propanol in hexane. The column was eluted isocrati-cally and monitored at 254 nm. 

High Pressure Liquid Chromatography High pressure liquid chromatography can be used as a screening procedure instead of radioimmunoassay, although it is less sensitive. Extract 10 ml of urine with 25 ml of methylene chloride, separate the solvent layer, and dry it over anhydrous sodium sulphate. Examine 10 al of the extract using a silica column (Zorbax SIL, 5 am) (System HT, p. 219). 

PMBOCH2CO2H (54), EDC, DMAP, CH2CI2, 45 °C, overnight then preparative HPLC (Zorbax Sil), 76 %. 

At this stage of the synthesis, the two diastereomers resulting from the preceding Grignard addition were separated by HPLC (Zorbax Sil) to afford ester 24 as a single diastereomer in 76 % yield. 

Ni coti ne,norni coti ne, cotinine Analysis in biological fluids Zorbax-Sil 250x4.6 Di oxane-i soprOH-NH OH(80 3 0.4) 10... 

LSD Comparison of photometric detectors for HPLC Zorbax Sil 250x2.1 CH2Cl2-Me0H-Ac0H(70 30 0.1) 4 ... 

Solanum and veratrum alkaloids Separation steroidal alka-loids(Fig.10.1 and 10.2) Zorbax Sil 6 Mm 250x4.6 n-Hexane-Me0H-Me,C0(18 1 1) n-Hexane-EtOH-Me CO(18 1 1) 4... 

Solasodine,various steroids Analysis in soianum species Zorbax Sil 6 wm 300x4.6 n-Hexane-Me0H-Me2C0(18 1 1) 6... 

Caf,Tb,Tp,8ClTp,dyp. prox Assay of Tp in plasma Zorbax Sil 6-8 imi 250x2.1 H,0 sat. CHCl,-heptane-EtOH-AcOH(600 400 0.8 64) 33... 

Caf,Tb,Tp,bamifylline, dyp.prox.lomifylline, pentifylline.pentoxi-fyl1ine Separation and analysis in plasma Spherisorb C6 5 (jn, Spherisorb CN 5 ym or Spherisorb ODS 5 ym 200x4.6 Zorbax Sil 7 ym 200x4.6 ACN-0.01M phosphate buffer (pH 2.7)(1 4),(28 72) Hexane-CHCl,-isoprOH-AcOH (50 43 5 2)J 152... 

Organic Nitrobenzene, methyl Zorbax SIL 6 p. Gradient 0.1% propan... 

Coliunn three 80 X 4 5 pm Zorbax SIL Reliance 5 columns in series... 

Column 250 X 4.6 5-6 pm Zorbax SIL Mobile phase n-Hexane THF 50 50 Flowrate 2 Ipjection volume 5 Detector UV 230... 

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