RP-HPLC analysis

APPLICATION METHANOL ELUENT RP-HPLC ANALYSIS FOR ESTERS OF 4-AMINOBENZENTHIOSULFINIC ACID AT PROCESS OF THEIR SYNTHESIS... 

Fmoc-substitution (note 5) 0.94 mmol g-1, 92% efficiency (typically 0.8-0.9mmol g 1 note 6) RP-HPLC analysis (Gl) of product obtained following acidolytic treatment (5% TFA in CH2C12, 5 min) showed the exclusive presence of Fmoc-NHOH. 

The derivatized resin product (100 mg, 0.08 mmol) was suspended in DCM (6 mL) for 30 min, after which 0.06 mL TFA was added and the resultant suspension was gently stirred for 15 min at ambient temperature. The suspension was filtered, the spent resin was washed with DCM (5 mL) and DCM MeOH (1 1, 5 mL), and the filtrate was evaporated to dryness in vacuo to give the title compound (29 mg, 90%) as white crystalline solid. RP-HPLC analysis (Gl) showed the exclusive presence (> 98%) of Fmoc-Phe-NHOH (Rt = 6.8 min). 

A comparative study was made of the RP-HPLC analysis of free amino acids in physiological concentrations in biological fluids, with pre-column derivatization by one of the four major reagents o-phthalaldehyde (73) in the presence of 2-mercaptoethanol, 9-fluorenylmethyl chloroformate (90), dansyl chloride (92) and phenyl isothiocyanate (97, R = Ph) (these reagents are discussed separately below). Duration of the analysis was 13-40 min. Sensitivity with the latter reagent was inferior to the other three however, its use is convenient in clinical analysis, where sample availability is rarely a problem. The derivatives of 73 were unstable and required automatized derivatization lines. Only 92 allowed reliable quantation of cystine. All four HPLC methods compared favorably with the conventional ion-exchange amino acid analysis188. 

The method was proposed for the approximate prediction of the retention of analytes in gradient elution and for the facilitation of the development of optimal gradient elution strategy [86], This prediction and optimization procedure is similar to those discussed above, consequently, its application in the field of RP-HPLC analysis of natural pigment may be similar. 

RP-HPLC found application in the monitoring of the alkali hydrolysis kinetics of alkali-clearable azo disperse dyes containing a fluorosulphonyl group. The chemical structures of dyes included in the experiments are shown in Fig. 3.85. Samples for RP-HPLC analysis were neutralized to pH 4.0 - 4.5 with diluted HC1 mixed with five volumes of ACN and injected without any other sample preparation step. Separation was carried out in an ODS column at ambient temperature. The isocratic mobile phase consisted of ACN-water (80 20, v/v) and dyes were detected at their absorption maxima. HPLC measurements indicated that dyes are easily hydrolysed under relatively mild alkaline conditions, and the hydrolysis follows a pseudo first-order kinetics [148],... 

A limit in data quality obtained by usual reversed phase (RP)-HPLC analysis of TAGs depends on their different degree of unsaturation this fact determines different spectroscopy characteristics. 

Figure 17 Elution Profiles for the Analytical RP-HPLC Analysis for the Purified (Insert Panel) and the Preparative RPC of the Crude Synthetic 22-mer Polypeptide Derived from the N-Terminal Secretory Leader Sequence of the Sperm Tail Protein, tpx-1, a Member of the Cystine-Rich Secretory Protein Superfamily 161 ab...

The protected bradykinin carboxylic acid was purified by precipitation from CHC13 with MeOH, and the purity was established by RP-HPLC and TLC Rf 0.6 (CHCl3/MeOH/AcOH 8 1 1) Rt 0.6 (EtOAc/ pyridine/AcOH/H20 60 20 6 11) on air-dried Merck Kieselgel 60 F254 glass plates. The purity of the protected bradykinin carboxylic acid was >90% based on RP-HPLC analysis. The amino acid composition was confirmed by a FAB-MS spectrum. 

Gonzalez de Llano et al. (47) separated amino acids from low-molecular-weight peptides by means of size-exclusion chromatography on Sephadex G-10, with water as the solvent, as a preparatory step before RP-HPLC analysis of peptides from blue cheeses soluble in 5% PTA (Fig. 1). This technique has also been used (51a) to eliminate the amino acids from the ethanol-... 

During the last two decades, RP-HPLC analysis has been successfully used to study anthocyanins in numerous foodstuffs. Because of the great number of publications, only a short excerpt from those many applications and corresponding HPLC-methods can be given in Table 6. To demonstrate the potential of this technique, an RP-HPLC separation of black currant juice is shown in Fig. 16. Despite the high costs of acquisition and maintenance, RP-HPLC will likely remain the best-qualified method for anthocyanin analysis in the coming years, because it offers,... 

Moret et al. (67,68) studied all the parameters that influence amine recovery under conditions where a liquid-liquid purification step with an organic solvent follows the acid extraction, prior to derivatization with DBS and RP-HPLC analysis. The optimized methods of sample preparation for different foods, including cheese, meat, and fish, are given. The same research group (69) optimized the extraction conditions for Phe, Put, Cad, His, Tyr, Spe, and Spd. Food samples were first mixed with TCA and centrifuged and then basified and extracted with BuOH/CHCl3 (1 1). The BAs were then derivatized with DNS and separated on a Spherisorb 3S TG column with an ACN-H20 gradient. The method was applied to samples of tuna, salmon, and salami. 

Figure 5 RP-HPLC Analysis of the Oxidation Reaction Mixtures for the Formation of Disulfide-Bridged Homo- (a) and Heterostranded (b) Coiled Coils and Gdn-HCl Titration Profiles of the Coiled Coils (c)P8] J>.c,d...

Figure 9 RP-HPLC Analysis of the Dimerization Behavior of c-Myc and Max Leucine Zippers Containing a N-Terminal Cys-Gly-Gly Linker (a) Equal Amounts of Reduced c-Myc and Max before Air Oxidation, (b) after 48 h of Air Oxidation, (c) before Equilibrium Redox Experiment, and (d) after Equilibrium Redox Experiment (after 24h)l61laJ ...

Resin-Bound 2-Methanesulfinyl-6-piperidinopyrimidine (9b) (R2NR2 = Piperidine) (lib). Resin 16 (500 mg, 0.50 mmol/ g loading, 0.25 mmol) is swollen in DMF (20 ml) for 30 min. The mixture is cooled to 0° and a solution of magnesium monoperoxyphthalate (MMPP, 212 mg, 0.34 mmol) in DMF (5 ml) is added dropwise and shaking continues for 2 h at 0°. After the resin is washed and dried in the usual manner, an aliquot of the resin (5 mg) is taken and cleaved off. RP-HPLC analysis indicates that approximately 6% starting material remained unreacted and a new oxidation cycle is performed with MMPP (0.14 mmol) for 1 h at 0°. Analysis confirmed the total conversion of resin 16 into a mixture of resin-bound sulfoxide (lib) ( 79%) and sulfone (11c) ( 15%). A theoretical loading of 0.50 mmol/g is assumed for subsequent work. 

Verdini, R. A., Zorrilla, S. E., and Rubiolo, A. C. (2004). Characterization of soft cheese proteolysis by RP-HPLC analysis of its nitrogenous fractions Effect of ripening time and sampling zone. Int. Dairy ]. 14, 445454. 

The introduction of "fast HPLC" has proven to be particularly valuable in protein analysis. As stated earlier, assay time in RP-HPLC analysis of proteins is typically long compared to that for smaller organic molecules. We have evaluated the use of 0.6-cm ID x 4-cm columns packed with 3-um particles in the analysis of insulin by RP-HPLC for potency determination, related substances, and in peptide mapping (7). The use of the "fast column" allows considerable savings (40-60%) in analysis time, compared to the regular (0.46-cm ID x 25-cm) columns, without loss in resolving power. 

A large number of organic sulfur compounds have been detected in extracts or distillates prepared from garlic, onions, or other Allium species. This chemistry has been reviewed by Block. Polysulfanes have been detected in many of these preparations but most recent results show that fresh extracts of garlic, prepared under mild conditions (20 °C), did not show any polysulfanes R-S -R n > 2) when analyzed by RP-HPLC analysis. ... 

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