Reverse-phase high-performance liquid following

Richfield-Fratz, N., Bailey, Jr., J. E., and Bailey, C. J., Determination of unsul-phonated aromatic amines in FD C Yellow No. 6 by the diazotization and coupling procedure followed by reversed-phase high-performance liquid chromatography, /. Chromatogr., 331, 109, 1985. 

We have followed the pathway of TNT degradation in the consortium using reverse phase high performance liquid chromatography (HPLC) and mass spectroscopy (MS). Analysis of the supernatant in the consortium showed sequential reduction of TNT to TAT however, TAT only occasionally accumulated, and even then only in very low concentrations. In addition, methylphloroglucinol (MPG) and />-cresol transiently appeared in the supernatant. All compounds were identified using HPLC by UV spectra and retention times as compared to authentic standards chromatographed under the same conditions. The mono- and diamino intermediates were also confirmed by the MS results. 

Fig. 2 Comparison of reversed-phase high-performance liquid chromatograms (obtained using 60-min gradients) of gliadins and glutenins extracted under reducing conditions from the wheat variety Neepawa using the following columns A, Zorbax Rx-300-C8 (first analysis) Zorbax Rx 300-C8 (450th analysis) C, Supelcosil LC-308 (first analysis) D, Zorbax Rx-300-CN (first analysis). 1,000 mv = 1 AU. (From Ref. 133.)...

N Richfield-Fratz, JE Bailey, CJ Bailey. Determination of unsulfonated aromatic amines in FD C yellow no. 6 by diazotization and coupling procedure followed by reverse-phase high performance liquid chromatography J Chromatogr 331 109-123, 1985. 

Alawi [319] has discussed an indirect method for the determination of nitrite and nitrate in surface, ground and rain water by reaction with excess phenol (nitrite ions first being oxidised to nitrate) and extraction of the o-nitrophenol produced, followed by separation on a reversed phase high performance liquid chromatography column with amperometric detection in the reduction mode. Recoveries were 82% for nitrate and 77% for nitrite in the concentration range 10-lOOOpg L 1. The method is claimed to be free of interferences from other ions. 

The exact mechanism(s) of solute retention in reversed-phase high-performance liquid chromatography (RPLC) is not presently well understood. The lack of a clear understanding of the mechanics of solute retention has led to a myriad of proposals, including the following partition (K21, L6, S16) adsorption (C9, CIO, H3, H15, H16, K13, L3, T2, U2) dispersive interaction (K2) solubility in the mobile phase (L7) solvophobic effects (H26, K6, M5) combined solvophobic and silanophilic interaction (B9, M12, Nl) and a mechanism based upon compulsary absorption (B5). 

The purity of crude peptide will be analayzed on a reverse-phase high-performance liquid chromatography (HPLC) column. The elution of the peptide is followed by absorbance recorded at 215 nm. The purification on a 10 to 20 mg scale is performed on a larger, preparative column monitored at the less sensitive wavelength of 238 nm. 

Thiols, as well as sulfide and sulfite, were determined in porewater samples by reversed phase high performance liquid chromatography (HPLC). The technique is based on precolumn derlvatization with an o phthalaldehyde/amine reagent (Figure 1) followed by HPLC and fluorometric detection. Derivatized porewater samples were Injected directly into the HPLC system the detection limit is 0.1 nM (for 100 ul injection). Details of the method are given in Mopper and Delmas (12). 

It is also possible to determine the level of metabolites in urine. Urinary 2-thiothiazolidine-4-carboxylic acid is the best available indicator to assess the degree of occupational exposure to carbon disulfide (ACGIH 1994 Theinpont et al. 1990). Theinpont et al. (1990) described the isolation of this compound from urine prior to reverse phase high-performance liquid chromatography. It is based on liquid-liquid extraction with methyl tertbutyl ether, followed by affinity chromatography on organomercurial agarose gel. The detection limit of the procedure was 50 g of carbon disulfide/L of urine (Theinpont et al. 1990). 

The amount of encapsulated model drug (retinyl acetate or progesterone) per mg of dried LS was determined through solubilization of LS in ethyl acetate at 60°C. Following filtration, the solution was analyzed by reverse-phase high-performance liquid chromatography (HPLC) to find the drug content. 

Fig. 3.5 Reverse-phase high-performance liquid chromatography (RP-HPLC) analysis of (A) rAHF and (B) rAHF-PFM following thrombin digestion. Samples of both products activated with thrombin show similar elution profiles and peak areas. The...

A single capillary scale reverse phase high-performance liquid chromatography system coupled online to automated electrospray ion trap tandem mass spectrometry (ID-LCMS) is usually performed to characterize the protein fractions. The following protocol is an example of the implementation of the method to identify the peptide components of tryptic digests of the yeast HPLC fractions analysis using the ion trap tandem mass spectrometer instrument described in Section 13.2.2.5, and typical results are shown in Figure 13.2-3. 

CE is a useful tool for monitoring the purity of metalloproteins isolated from either natural or recombinant sources. CZE was used to follow the purification progress of metallothioneins in samples subjected to gel filtration chromatography and reversed-phase high-performance liquid chromatography (HPLC). " Detection of a unique chromophore arising from the interaction of metal ions... 

Unfortunately, the labeled 9Z,11E) CLA isomer was contaminated with (9 ,11 ) isomer and oveneduced fatty adds. Purification by C18 reversed-phase high-performance liquid chromatography (RP-HPLC) followed by silver resin chromatography furnished pure methyl (9Z,llfi)-[9,ll-2H]-octadecadienoate (isomeric purity >99% isotopic purity 82-88%) in 60-70% overall yields. In this paper, the author also noticed that increasing the ratio of quinoline to substrate and the volume of solvent resulted in improved chemical and isotopic yields, but the formation of overreduced by-products could uot be prevented. 

Enzymatically released aromatic PET degradation products can be monitored by UV detection at 240-255 nm, following separation by reversed-phase high performance liquid chromatography (HPLC). Soluble hydrolysis products of PET films, fibers, and cyclic PET trimers (CTR) that have been identified include TPA, mono(2-hydroxyethyl) terephthalate (MHET), Z A(2-hydroxyethyl terephthalate) (BHET), 1,2-ethylene-mono-terephthalate-OTono(2-hydroxyethyl terephthalate) (EMT), and 1,2-ethylene-/ A-terephthalate (EBT) [8, 33, 38, 40, 90, 102] (Fig. 1). 

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