Diphenyl column

The TH peptide was purified initially by preparative RP-HPLC on a Rainin AutoPrep System with a Vydac 218TP152022 C18 column (15-20-pm particle size, 300-A pore size, 250 x 22 mm) at a flow rate of 5.0 mL -min The elution gradient was 0-100% B in lOOmin, where A was 0.1% TFA in H20 and B was 0.1% TFA in MeCN, with detection at 229 nm. 1-min fractions were collected, with 10 pL from each fraction used for analytical RP-HPLC. Selected fractions were further purified by semi-preparative RP-HPLC on the same system equipped with a Vydac 219TP510 diphenyl column (5-pm particle size, 300-A pore size, 250 x 10mm) at a flow rate of 2.0mL-min The elution gradient was 0-70% B in 70min, where A was 0.1% TFA in H20 and B was 0.1% TFA in MeCN, with detection at 229 nm. 30-s fractions were collected, with 10 pL from each fraction used for RP-HPLC peptide analyses.1851... 

Analyze the efficiency of protein insertion by RP HPLC on Vydac Diphenyl column with elution at 0.75 mL/min with 50 mM thriethylamine phosphate pH 2.8 and 20% tetrahydrofuran with a linear gradient of acetonitrile (0-70% v/v over 25 min). 

The following examples will be used to demonstrate that medium-polarity reversed phases have great potential for protein separations. In Fig. 7 the separation of the C apolipoproteins is shown on a phenyl and on a Ci8 column. The Cig column gave almost no separation of the protein mixture, despite the use of a variety of mobile-phase conditions, whereas the phenyl column gave an excellent separation. Lewis et al. (34) found that the columns of intermediate polarity were effective in the separation of tyrosinase, collagen i, cytochrome c, and bovine serum albumin. In this study the diphenyl column was more retentive than the octyl or nitrile... 

Yang and Khaledi [27] applied LSER to the evaluation of the retention behavior (k and K m) of uncharged substituted aromatic compounds of diverse hydrophobicity, using C8 and diphenyl columns, and pure and hybrid mobile phases of SDS and C14TAB with 2-propanol and 1-butanol as modifiers. Zou et al. [28] made a similar study with K m and P s, and found high correlations between the retention and solvatochromic parameters of solutes. 

Figure 9.11 Correlations between log 1/C and k (or log k ), for a series of 26 p-substituted phenols eluted with 0.04 M CTAB (top, r = 0.917), 0.04 M CTAB-10% 2-propanol (middle, r = 0.946), and methanol-water 40 60 (v/v), (bottom, r = 0.812). A diphenyl column was used. Reprinted from Ref 30 with permission of the American Chemical Society.

In addition to decreased carryover, another advantage that UHPLC offers for protein analysis is speed. In one study, three columns with different stationary phases were evaluated for antibody-free thiol variant separation Waters Acquity BEH Cg (1.7 p.m), Agilent diphenyl (3.5 p-m), and Agilent Eclipse Cig (1.8 pm) (26). The results demonstrated that free thiol variants could be separated in less than 3 min as shown in Figure 8.2, with the Cig column demonstrating better resolution compared to the Cg and diphenyl columns. 

A mixture of 56.8 g (0.21 mol) of diphenyl phosphorochloridate (Note 1), 16.3 g (0.25 mol) of sodium azide, and 300 mL of anhydrous acetone (Note 2) in a 500-mL round-bottomed flask fitted with a calcium chloride tube is stirred at 20-25°C for 21 hr. The lachrymatory mixture is filtered in a hood, and the filtrate is concentrated under reduced pressure. The residue is distilled through a short Vigreux column (Note 3). The yield of diphenyl phos-phorazidate, bp 134-136 C (0.2 ram), is 49-52 g (84-89 ) (Note 4). 

Biphenylyl diphenyl phosphate [132-29-6] M 302.4, n l.5925. Vacuum distd, then percolated through an alumina column. Passed through a packed column maintained at 150° to remove residual traces of volatile materials by a counter-current stream of nitrogen at reduced pressure. [Dobry and Keller J Phys Chem 61 1448 1957.]... 

Diphenyl tolyl phosphate [26444-49-5] M 340.3, n 1.5758. Vac distd, then percolated through a column of alumina. Finally, passed through a packed column maintained at 150 to remove traces of volatile... 

When TBTO is released into ambient water, a considerable proportion becomes adsorbed to sediments, as might be expected from its lipophilicity. Studies have shown that between 10 and 95% of TBTO added to surface waters becomes bound to sediment. In the water column it exists in several different forms, principally the hydroxide, the chloride, and the carbonate (Figure 8.5). Once TBT has been adsorbed, loss is almost entirely due to slow degradation, leading to desorption of diphenyl-tin (DPT). The distribution and state of speciation of TBT can vary considerably between aquatic systems, depending on pH, temperature, salinity, and other factors. 

Catechin-immobilizing polymer particles were prepared by laccase-catalyzed oxidation of catechin in the presence of amine-containing porous polymer particles. The resulting particles showed good scavenging activity toward stable free l,l-diphenyl-2-picryl-hydrazyl radical and 2,2 -azinobis(3-ethylbenzothiazoline-6-sulfonate) radical cation. These particles may be applied for packed column systems to remove radical species such as reactive oxygen closely related to various diseases. 

Typical operating conditions by GC and HPLC are listed in Tables 2 and 3, respectively. Anilides are separated using a weakly polar liquid-phase capillary column, such as SPB-1 or HP-5, which is prepared based on 5% diphenyl-95% dimethylpolysilox-ane for GC. For HPLC, ODS columns are used. 

Multiresidue analysis of 72 pesticides including three diphenyl ethers was carried out by GC/NPD under the following conditions column, 5% DB-5 (30 m x 0.53-mm i.d., 0.53- xm film thickness) temperature, column 100°C(1 min) increased at 5 °Cmin to 280°C (lOmin), inlet and detector 280°C gas flow rates. He 11.2mLmin H2 3.5mLmin air llOuiLmin" injection volume, 2 rL. The retention times... 

Diphenyl ether herbicides are generally extracted from 10 to 50 g of air-dried soil with an organic solvent such as acetone, methanol and benzene by sonication, mechanical shaking or Soxhlet extraction. If necessary, the extracts are then cleaned by column chromatography or SPE. The extract is evaporated completely to dryness and the residue is dissolved in an appropriate volume of the solvent for GC analysis. The reduced amine metabolites are extracted under alkaline conditions. 

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