Acetonitrile gradient

Histones (from S4A mouse lymphoma). Purification used a macroprocess column, heptafluorobutyric acid as solubilising and ion-pairing agent and an acetonitrile gradient. [McCroskey et al. Anal Biochem 163 427 1987.]... 

Similar results were shown for the analysis of alkylphenol ethoxylates, which could only be separated on Spherisorb silica using acetonitrile and water (Rissler 1994). Since water-acetonitrile gradients give better resolution over water-methanol gradients for the analysis of PEG S, it was proposed that methanol shields residual... 

OPA-derivatized amino acids are usually separated on an ODS-II solid phase using a mobile phase of sodium phosphate buffer and an acetonitrile gradient. 

Fig. 2.7.2. (—)-LC-ESI-MS chromatograms of a standard APG solution, (a) Total ion current trace fromm/2 200 to 600. (b)XIC of Cg-, C10-, and Ci2-monoglucoside, and (c) XIC of Cg-, C10-, and Ci2-diglucoside. Peak numbering as in Table 2.7.1 indices a and b denote different stereoisomeric forms. (Separation on a RP-Cg column with a water/acetonitrile gradient) (Reprinted from [1],...

Mobile-phase Water/Acetonitrile-Gradient Elution Detector UV 254 nm... 

High-performance liquid chromatography (HPLC) techniques are widely used for separation of phenolic compounds. Both reverse- and normal-phase HPLC methods have been used to separate and quantify PAs but have enjoyed only limited success. In reverse-phase HPLC, PAs smaller than trimers are well separated, while higher oligomers and polymers are co-eluted as a broad unresolved peak [8,13,37]. For our reverse-phase analyses, HPLC separation was achieved using a reverse phase. Cl8, 5 (Jtm 4.6 X 250 mm column (J. T. Baker, http //www.mallbaker.com/). Samples were eluted with a water/acetonitrile gradient, 95 5 to 30 70 in 65 min, at a flow rate of 0.8 mL/min. The water was adjusted with acetic acid to a final concentration of 0.1%. All mass spectra were acquired using a Bruker Esquire LC-MS equipped with an electrospray ionization source in the positive mode. 

In another study, Kalghatgi et al. [36] looked at the purification of mellittin, a 26-amino-acid peptide derived from bee venom, using micropellicular C18 stationary phases. Rapid HPLC analysis (1 min acetonitrile gradient at 80°C) of a commercially derived melittin sample revealed a complex mixture (Figure 11.14). 

The quaternary ammonium compounds paraquat and diquat are widely used non-selective contact herbicides, which are extremely toxic to humans. Fee et al. [112] established an HPLC-MS-MS procedure for the determination of these herbicides in whole blood and urine using ethyl paraquat as internal standard. After extraction with Sep-Pak C18 cartridges, analytes were separated using ion pair chromatography with heptafluorobutyric acid in 20 mM ammonium acetate and acetonitrile gradient elution. Detection was carried out in ESI MS-MS SRM mode. Using similar separation and detection conditions, paraquat, diquat, difenzoquat, and a number of structurally related quaternary nitrogen muscle relaxants (see Section 20.2.1.3) were determined in whole blood by Ariffin and Anderson [113]. 

Fig. 15. Memory effect. Gradient elution of 500 pg phosphorylase kinase on a RP 18 column (250 x 4.6 mm dP = 5 pm). Mobile phase A 0.1% TFA in water B 0.08% TFA in acetonitrile gradient program 0 % B (0-8 min), 46 % (9 min) 68 % (24 min), 75% (33 min) flow rate 1 ml/min. The lower chromatogram was obtained upon sample injection the five blank gradients were performed immediately after the initial separation. Molar mass of the subunits a — 132,000 daltons P — 113,000 y - 43,000 5 - 16,680. (From Ref. 66> with permission)...

Recovery of only 20 % was observed in the separation of influenca virus components on a RP column (250x4.6 mm dG = 30 nm) with a water/acetonitrile gradient. The virus consists of three protein components with molar mass alues ranging from 28 to 55 kg/mol. After several runs, the column back pressure increased from 60 to 90 bars. Overnight treatment with 0.1 % sodium dodecylsulfate and 0.05 % TFA helped to regain approximately the initial permeability 67 ... 

Phenyl-oligo(ethylene glycol) homologs were separated into individuals on a C 8 column (250x4.6 mm d0 = 6 nm dP = 7 pm) with a water/acetonitrile gradient (from 20 to approximately 33 % B in 30 min) at 2.0 ml/min flow rate87) (Fig. 24). 

For the investigation of a butadiene-styrene rubber, a set of three SEC columns in series was used 500 x 8 mm, d0 = 150 nm 500 x mm, d0 = 25 nm 800 x 8 mm, d0 = 4 nm, all three with dP = 10 pm. The flow rate was 1 ml/min. The injection amounted to 200 pi of a 2 % solution from which the carbon black had been removed. Although the additives of interest were separated from the polymer, they were still covered by an intense band from process oil. Hence, coupled-column chromatography with reversed-phase separation of SEC eluates became neccessary. 10 pi of the latter were injected into a C 8 column (250 x 2.2 mm dP = 10 pm) and analyzed at 0.5 ml/min flow rate through a water/acetonitrile gradient (rising from 20% B by 6%/ml). Here, UV detection was performed at 254 nm. The peaks of the additives could be clearly separated from the process oil band. The technique also proved useful for checking... 

Figure 10.9 HPLC trace of standard pigments using gradient elution system, (a) standard mixture (1) monitored at 415 nm (b) standard mixture (2) monitored at 490 nm and 590 nm. Conditions column 5 pm ( IS 150 X 4.6 mm, using diode array detection at 450 nm and gradient elution solvent A = 0.02 M ammonium acetate, Solvent B = acetonitrile gradient profile 0 min 95% A, 20 min 50% A, 25 min 95% A flow rate 1.0 ml/min.

Link et al. have used a two-dimensional chromatographic separation approach to characterize yeast ribosome complex proteins (Link, 1999). This technique employs a cation exchange column (SCX) for the first separation and, subsequently, two parallel reversed-phase HPLC columns (Figure 15.4), and thus works extremely rapidly and efficiently. While the first column loads, the second elutes using an acetonitrile gradient The flow from the column is directed to parallel online MS detectors as well as to offline fraction collection with UV detectors. 

AT Aqueous environment Genesis C column (2.1 mm x 50 mm, 3 fim) Acetonitrile (gradient from 60% to 100%) and water containing 2 mM methyl amine with 0.1% acetic acid Electrospray ionization (ESI) tandem mass spectrometry [15]... 

Methanesulfonic acid Methanesulfonic acid/ acetonitrile gradient... 

TMS bonded WLCU Si gel 0.1M HCIO4 in water-acetonitrile gradient 85 15 to 70 30... 

Figure 6. Reversed-phase HPLC of rt-PA. The chromatography was performed on a Vydac C4 column using TFA-containing mobile phases and eluted with an acetonitrile gradient from 32 to 40%.

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