A- acetonitrile

A, acetonitrile and a perchlorate salt such as LiC104 or a tetraalkyl ammonium salt... 

Figure 14 Separation of 1,2/1,4 ketal with and without protection from oxidative degradation. Chromatographic conditions were column 25 cm x 4.6 mm Zorbax C8 (5-pm) column mobile phase 100 mM KH2P04 (pH 6.5) acetonitrile (50 50) flow rate 1.0 ml/min column temperature 35°C detector wavelength 220 nm. (A) Acetonitrile degassed. (B) Acetonitrile not degassed.

Fig. 12.1 Typical chromatogram containing A, acetonitrile B, 2-chloroethanol C, 4ng of 2 bromoethanol D, ethane-1,2-diol E, 2-iodoethanol F, acetamide Q unknown and H, 2,2 -dihydroxydiethyl ether.

FIGURE 12. Reaction rates, kA(f), of DNF (2,4-dinitrofluorobenzene) with aniline in A acetonitrile (xlO4) ethyl acetate (xlO4) A chloroform (xlO7) and toluene (xlO7) as a function of [aniline] O in toluene (5 x 104) as a function of [pyridine]190... 

Figure 3.9 Elution volumes (ml) of alternative void volume markers. Column, 5 im octadecyl-bonded silica gel, 15 cm x 4.5 mm i.d. eluents A and B, 10-90% aqueous acetonitrile, eluents C and D, 10-90% aqueous acetonitrile containing 50 mMphosphoric acid flow rate, 1 ml min temperature, 30 °C detection, UV 210 nm and refractometer. Sample a, acetonitrile b, methanol c, fructose d, 2,4-dinitronaphthol e, sodium nitrate, f, tetrahydrofuran g, deuterium oxide, and h, uric acid.

FIGURE 1.30 Micro-HPLC separation of all 4 stereoisomers of the dipeptide alanyl-alanine as FMOC derivatives (a) and DNP-derivatives (b), respectively, on a 0-9-(tert-butylcarbamoyl)quinine-based CSP. Experimental conditions Column dimension, 150 X 0.5 mm ID mobile phase (a) acetonitrile-methanol (80 20 v/v) containing 400 mM acetic acid and 4 mM triethylamine, and (b) methanol-0.5 M ammonium acetate buffer (80 20 v/v) (pHa 6.0) flow rate, 10 ixLmin temperature, 25 C injection volume, 250 nL detection, UV at 250 nm. (Reproduced fromC. Czerwenka et al., J. Pharm. Biomed. Anal., 30 1789 (2003). With permission.)... 

Analysis of the Copolymerizabilities of Monomers The composition of the copolymers formed was determined by measuring the relative amounts of each monomer, NIPAAM and AAM, that remained in solution after a copolymerization. Copolymerizations were terminated by addition of 1 ml of reaction mix to 9 ml of 0.1% phosphoric acid at 50 C, followed by centrifugation of a 0.4 ml aliquot at 6,500 x g for 5 minutes in an Eppendorf microfuge. After 100 fold dilution of an aliquot of the supernate, 200 pi of this was injected onto an IBM reversed phase Cig HPLC column pre-equilibrated with 2% acetonitrile in 0.1% aqueous phosphoric acid and the eluent monitored at 214 nm. The monomers were eluted using a 0.1% aqueous phosphoric acid (solvent A) acetonitrile (solvent B) gradient as follows for 5 minutes the solvent was 98% solvent A and 2% solvent B, followed by a linear gradient to 80% A and 20% B over 10 minutes. After 5 more minutes at 80% A and 20% B, the solvent was returned to 98% A and 2% B. 

Measurement of Dorzolaniide in Plasma IV Beckman RP-8 (250 X 4.6 mm, 5pm) Solvent A Acetonitrile Solvent B Sodium salt of octanesulfonic acid in 0.085% phosphoric acid in water 25% solvent A 75% solvent B 252 nm 13. 

Yamamoto et al. (141,142) succeeded in carrying out catalytic versions of the above reaction by using of a slow in situ generation of the nitrile oxide by the slow addition of triethylamine to a acetonitrile solution of the hydroximoyl chloride precursors. Both MgBr2 and Yb(OTf)3 are effective as promoters in these cases. The use of Lewis acid-alcohol mixtures such as Mg(C104/EtOH (1 1) and La(OTf)3/j-PrOH (1 1) is even more effective (Scheme 11.37). 

Mobile phase 1 % acetic acid (A) acetonitril (B) Flow rate 2 ml/min... 

Abbreviations THF, tetrahydrofuran D, dioxane A, acetonitrile py, pyridine bipy, 2,2 -bipyridyl phen, o-phenanthroline B, o-phenylenebis(dimethylarsine). For cir (C ) complexes four v(MCl) are allowed in the IR spectra (2A, + Bt + B2) whereas for trans (Dih) complexes only one v(MCl) mode is allowed ( ) these complexes are considered to have the cis (C ) structure. 

The reverse-phase analysis was carried out on a SUPELCOSIL LC-18, 3-/zm particle size, 150 X 4.6-mm ID column (solvent system A, acetonitrile B, acetonitrile-tetrahydrofuran-chloroform (50 27.5 22.5) linear gradient from 30% to 100% of B in 70 min, flow rate 0.5 ml/min) (Fig. 22). The upper part of Fig. 22 shows that various chain lengths (C12 to C24 with one-carbon increment) of PNB-TBDMS-OHFA separated well enough in 30 min for effective recovery of the components by an absorbance slope-detecting fraction collector-detector combination. The separation of the positional isomers present in the used mixture was only minor, and it did not interfere with the fractionation according to chain length. 

Fig. 35 Separation of a standard TGs mixture (G No. 1, Nu-ChekPrep.). Linear gradient from 100% A to 100% B in 120 min. Column 250 X 4.6-mm ID. LICHROSPHERE 100 RP18 solvent A acetonitrile solvent B acetonitrile/ethanol/hexane (40 40 20 w/w/w) flow rate l.Oml/min.

Riboflavin, Liver beef Addition of 7-ethyl- Precolumn A acetonitrile. Fluorescence Internal standardization using 83... 

CNCbl, HOCbl, Milk dairy Extraction and protein Analytical A acetonitrile. Detection of vitamers in External standardization. 177... 

Mobile phase Eluent (A) acetonitrile eluent (B) 1% acetic acid in water... 

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