HPLC characterization

Folonari, C. V. and Garlasco, R., Ion-paired HPLC characterization of cathodic electrodeposition paint polymers, /. Chromatogr. Sci., 19, 639, 1981. 

Tea is known to be a good sonrce of phenolic substances and its earliest HPLC characterization was pnblished in 1976 [359] The introdnction of DAD as a detection technique for HPLC greatly improved the possibility of fully characterizing it. In 2004, Yao et al. [360] published a study on tea cnltivated in Anstralia six phenolic acids were identified, including p-coumarylquinic, p-coumaric, and 3-(p-hydroxyphenyl) propionic acid. Previously, Bonoli et al. [361] carried out a comparison of HPLC with capillary electrophoresys and concluded that the latter shows advantages in terms of the time of analysis with respect to HPLC, even if in 2004, Pelillo et al. [362] were able to develop a fast analysis by means of HPLC. 

Caron, F., Elchuk, S. Walker, Z. H. 1996. HPLC characterization of dissolved organic matter from low-level radioactive waste leachates. Journal of Chromatography, 739, 281-294. 

Unfortunately, the condensation products exceed the volatility range amenable to gas chromatography (GC). Moreover, (I) does not possess a strong chromophore for easy high pressure liquid chromatography (HPLC) characterization. SFC with flame ionization detection obviates these difficulties. 

Acrylic Crosslinkers. Butanediol diacrylate (IV) (BDDA) is a popular crosslinker used in the preparation of many polymers used for inks, paints, and plastics. Low-levels of impurities can adversely affect product properties. As previously discussed, K+IDS provides a powerful qualitative technique, but yields poor quantitative data when analyzing volatile chemicals. BDDA is amenable to analysis by GC, unfortunately any higher-molecular-weight adducts exceed the volatility range amenable to GC. Moreover, BDDA is not chromophoric thereby HPLC characterization is also difficult. 

Case Study A.7 Scaled-Up Acid Degradation and Isolation Using Preparative HPLC Characterization by LC/MS, NMR, and IR Spectroscopy... 

The HPLC characterization of the major 3,4-dihydro-2i/-l,2,4-benzothiadiazine 1,1-dioxide diuretics has been discussed in detail <85JC395>, and their racemic mixtures have been resolved into the pure enantiomers by liquid chromatography on a variety of stationary phases including chiral polyacrylamides (1 1 toluene-dioxan as eluant) <85JPS438>, (R)(-l-)-camphanic acid and V-(IS)-... 

RP-HPLC CHARACTERIZATION OF ENZYMATIC HYDROLYSIS OF WHEY PROTEINS... 

Figure 2 HPLC characterization of (A) Hb-bound NO and (B) heme of SNO-PEG-Hb. (A) Samples were separated on a gel-filtration cohimn (8 x 300 mm, GFC-200, Eicom, Kyoto, Japan) eluted with 10 mM acetate buffer, 0.1 mM EDTA, 100 mM sod him chloride, pH 5.5, at the flow rate of 0,55 mlAnin. The eluate was mixed with 1.75 mM mercury chloride at the flow rate of 0.20 mlVmin to decompose S-nitiosylated protein, and further mixed with Griess reagent at the flow rale of 0.22 mlAnin. The red azo-dye formed was determined by the absorption at 540 nm. (B) For the characterization of molecular weight distribution, proteins were sqiarated on a gel-filtration column (7.6 x 300 mm, TSK G3000SW, Toyo Soda Co. IM Tokyo, Japan) in 10 mM sodium phosphate buffer, 100 mM sodium chloride, pH 6.9, at the flow rate of 0.9 mL/min. Proteins were monitored at 420 nm for heme and at 280 nm for molecular weight markers.

Hamper BC, Synderman DM, Owen TJ, Scales AM, Owsley DC, Kesselring AS, Chott RC. High-throughput H-1 NMR and HPLC characterization of a 96-member substituted methylene malonamic acid library. J Comb Chem 1999 1 140-150. 

Takano, A., Kushida, Y., Aoki, K. et al. (2007) HPLC characterization of cycUzation reaction product obtained by end-to-end ring closure reaction of a telecheUc polystyrene. Macromolecules, 40,679-681. 

In more recent publications the analytical standards have been raised considerably (HPLC, H-NMR, CD R.F. Nutt, 1980), and one may predict that in the near future it will be possible to characterize fully synthetic oligopeptides of moderate size. 

These methodologies have been reviewed (22). In both methods, synthesis involves assembly of protected peptide chains, deprotection, purification, and characterization. However, the soHd-phase method, pioneered by Merrifield, dominates the field of peptide chemistry (23). In SPPS, the C-terminal amino acid of the desired peptide is attached to a polymeric soHd support. The addition of amino acids (qv) requires a number of relatively simple steps that are easily automated. Therefore, SPPS contains a number of advantages compared to the solution approach, including fewer solubiUty problems, use of less specialized chemistry, potential for automation, and requirement of relatively less skilled operators (22). Additionally, intermediates are not isolated and purified, and therefore the steps can be carried out more rapidly. Moreover, the SPPS method has been shown to proceed without racemization, whereas in fragment synthesis there is always a potential for racemization. Solution synthesis provides peptides of relatively higher purity however, the addition of hplc methodologies allows for pure peptide products from SPPS as well. 

In this work the state-of-the-art and perspectives of column characterization and compai ison have been presented and discussed. All information about physico-chemical properties of RP HPLC Cl8 and C8 columns as porosity, average surface area, free silanol concentration, binding ligand density and others, were summarized. The points of views about column classifications, its advantages and disadvantages were discussed. It was shown that Cl8 and C8 HPLC column classification processes do not allow selecting the column with the same or preai range selectivity. 

Acidimetric, spectrophotometric and HPLC assays were developed for determination of 2,3,5,6,7,8-hexahydro-l//-pyrido[l,2-c]pyrimidine-l,3-diones 135 (98M133). Its solubility properties were also characterized. Resolution of the enantiomers of 4-phenyl-2- 4-[4-(2-pyrimidinyl)piperazi-nyl]butyl perhydropyrido[l,2-c]pyrimidine-l,3-dione was achieved on hep-takis(2-N, V-dimethylcarbamoyl)- 6-cyclodextrines (01 JC(A)249). 

A number of analytical techniques such as FTIR spectroscopy,65-66 13C NMR,67,68 solid-state 13 C NMR,69 GPC or size exclusion chromatography (SEC),67-72 HPLC,73 mass spectrometric analysis,74 differential scanning calorimetry (DSC),67 75 76 and dynamic mechanical analysis (DMA)77 78 have been utilized to characterize resole syntheses and crosslinking reactions. Packed-column supercritical fluid chromatography with a negative-ion atmospheric pressure chemical ionization mass spectrometric detector has also been used to separate and characterize resoles resins.79 This section provides some examples of how these techniques are used in practical applications. 

Thin-layer chromatography (TLC) is used both for characterization of alcohol sulfates and alcohol ether sulfates and for their analysis in mixtures. This technique, combined with the use of scanning densitometers, is a quantitative analytical method. TLC is preferred to HPLC in this case as anionic surfactants do not contain strong chromophores and the refractive index detector is of low sensitivity and not suitable for gradient elution. A recent development in HPLC detector technology, the evaporative light-scattering detector, will probably overcome these sensitivity problems. 

Alcohol sulfates can be characterized by HPLC. Their molecular structure does not permit a direct UV detection but an indirect UV detection of the alcohol sulfate is possible [285]. The detection can be made by the change in UV absorbance of the mobile phase, either by using an ion exchange column contain-... 

In 1979, it was stated that poiybrominated aromatic ethers have received little attention (ref. 1). That statement is still applicable. Analyses to characterize this class of commercial flame retardants have been performed using UV (refs. 1-2), GC (refs. 1-6), and GC-MS (refs. 1-4). The bromine content of observed peaks was measured by GC-MS, but no identification could be made. The composition of poiybrominated (PB) diphenyl ether (DPE) was predicted from the expected relationship with polyhalogenated biphenyl, a class which has received extensive attention. NMR (refs. 3-6) was successfully used to identify relatively pure material which had six, or fewer, bromine atoms per molecule. A high performance liquid chromatography (HPLC) method described (ref. 1) was not as successful as GC. A reversed phase (RP) HPLC method was mentioned, but no further work was published. 

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