High performance liquid chromatography HPLC analysis

Paganga, G. et al.. The polyphenolic content of fruit and vegetables and their antioxidant activities what does a serving constitute Free Radical Res., 30, 153, 1999. Maatta, K.R. et al.. High-performance liquid chromatography (HPLC) analysis of phenolic compounds in berries with diode array and electrospray ionization mass spectrometric (MS) detection Rihes species, J. Agric. Food Chem., 51, 6736, 2003. 

The concentrated eluate is subjected to high-performance liquid chromatography (HPLC) analysis. 

Plant materials are homogenized with methanol. Hexythiazox residue is extracted with hexane and then transferred to acetonitirile by liquid-liquid partitioning. The acetonitirile is removed by rotary evaporation and the sample is cleaned up using Florisil PR column chromatography. The concentrated eluate is subjected to high-performance liquid chromatography (HPLC) analysis. 

Adaptation of the modified factorial techniques to desktop computers has also been accomplished [24, 25]. Down et al. [25] presented this concept and applied the programs to a tablet problem. The statistics involved were presented in some detail. A similar design was also used to study a high-performance liquid chromatography (HPLC) analysis [26]. In an unusual application, optimization techniques were even used to study the formulation of a culture medium in the field of virology [27]. 

Nitrobenzene oxidation was carried out by adding 50 mg of dry soda lignin into a mixture of 7 mL of 2 M NaOH and 4 ttiL of nitrobenzene in a 15 ttiL steel autoclave. Then, the antoclave was heated to 165°C for 3 hours in a preheated thermostat oil bath. After the autoclave was cooled to room temperature, the mixture was then transferred to a liqnid-hquid extractor for continuous extraction with chloroform (5 x 20 mL) in order to remove any nitrobenzene reduction product and excess nitrobenzene. The oxidation mixtnre was then acidified by concentrated HCl to pH 3 and further extracted with chloroform (5x15 mL). The solvent from the second chloroform solution was then removed using a rotary evaporator at 40°C under reduced pressure in order to obtain the nitrobenzene oxidation mixture. The mixture was then dissolved into dicloromethane and made up to 10 luL. This mixture was then used as a stock solution for high performance liquid chromatography (HPLC) analysis [6]. 

For high-performance liquid chromatography (HPLC) analysis samples (0.5 mL) were clarified by centrifugation at 14000 Gav for 5 min and the supernatant was decanted, filtered through a 0.2 yim in-line syringe filter and analysed directly by chiral HPLC (see below). 

The purity of all lipids and anthracyclines exceeded 98% based on thin-layer chromatography (TLC) and/or high-performance liquid chromatography (HPLC) analysis, performed as described by Barenholz and coworkers (38,49,50). 

Evaporate a 5- ll aliquot to dryness under a vacuum. Redissolve the residue in a suitable buffer prior to analysis by an amino acid analyzer or into the appropriate eluant if high performance liquid chromatography (HPLC) analysis is used. 

Restricted rotation, as surface conjestion increases, was postulated as being responsible for the observed optical rotations as the generations increase,1251 the possibility of racemization during amino acid acylation was also investigated. Amino acid isolation and high-performance liquid chromatography (HPLC) analysis following acidic hydrolysis of the asymmetric dendrimers revealed an enantiomeric excess > 96 %. 

There are two main procedures for measuring PI 3-kinase activity which measure lipid kinase activity in intact cells or broken cell lysates respectively, and both rely on detecting the transfer of the y- phosphate of ATP to the D-3 position of the inositol head group of phosphoinositide lipids. The first method relies on metabolic labeling of intact cellular pools of ATP with [32P]Pi followed by lipid extraction (3,4) and separation of the phosphorylated lipids by high-performance liquid chromatography (HPLC) analysis (5). The advantages of this procedure are ... 

The analysis of tropane alkaloids by liquid chromatography has been performed for over 30 years. The first high-performance liquid chromatography (HPLC) analysis of tropane alkaloids was published in 1973 and concerned the separation of atropine and scopolamine as well as homatropine and apoatropine [102] the first analysis of these compounds in plant material appeared 12 years later [103]. 

Cautela, D. Laratta, B. Santelli, F. Trifiro, A. Servillo, L. Castaldo, D. 2008. Estimating Bergamot juice adulteration of lemon juice by high-performance liquid chromatography (HPLC) analysis of flavanone glycosides. J. Agric. Food Chem. 56 5407-5414. 

The determination of amino acids in various samples is a usual task in many research, industrial, quality control, and service laboratories. Hence, there is a substantial interest in the high-performance liquid chromatography (HPLC) analysis of amino acids from many diverse areas like biochemistry, biotechnology, food quality control, diagnostic services, neuro-chemis-... 

Fig. 3 Chromatograms obtained by pH zone-refining CCC. (A) Separation of CBZ(Z) dipeptides. Experimental conditions are as follows apparatus type-J multilayer CPC (PC Inc., Potomac, MD, USA) with a 10-cm revolution radius column multilayer coil, 1.6-mm ID, 325 mL capacity solvent system methyl tert-h xiy ether/acetonitrile/water (2 2 3), 16 mM TEA in organic phase (pH 1.83), and 5.5 mM NH3 in aqueous phase (pH 10.62) sample eight CBZ(carbobenzyloxy) dipeptides as indicated in the chromatogram, each 100 mg in 50 mL of solvent (25 mL in each phase) flow rate 3.3 mL/hr in head-to-tail elution mode detection 206 nm revolution 800 rpm retention of stationary phase 65.1%. (B) Separation of bacitracin complex. High-performance liquid chromatography (HPLC) analysis indicated that two major components, bacitracins A and B, were isolated in peaks 3 and 5, respectively. Experimental conditions are as follows apparatus and column same as above solvent system methyl r -butyl ether/ acetonitrile/water (4 1 5), 40 mM triethylamine, 10% DEHPA in the organic stationary phase, and 20 mM HCl in aqueous mobile phase flow rate 3 mL/min sample 5 g of bacitracin dissolved in 40 mL of solvent (20 mL in each phase) revolution 800 rpm detection 280 nm.

There are other examples of HIV protease substrates that utilize the fluorescence energy transfer technique. Perhaps the strongest characteristic of these assays is that they provide a continuous readout of enzyme activity. Another advantage is their sensitivity (they use small concentrations of enzyme). The disadvantage of these assays is that they are susceptible to interference by some compounds (inhibition artifacts) because of inner and outer filter effects (see Notes 8-10). Other assays, for example, those based on radioactivity or high-performance liquid chromatography (HPLC) analysis of products are tedious to run, but are less susceptible to interference or inhibition artifacts. 

The preferred blood sample is one collected with either K or Na salts of ethylenediaminetetraacetic acid (EDTA) as the anticoagulant. To minimize the formation of degradation products, which are especially noticeable as small bands eluting with similar retention time as Hb Ai and Hb F on high-performance liquid chromatography (HPLC) analysis, testing should be performed within 5 days of collection and samples should be stored at 4 "C. 

A solvent module (Varian model No. 5000) with a UV detector coupled to an on-line Nal(Tl) detector was used for high performance liquid chromatography (HPLC) analysis. For radioactive measurements, a dose calibrator (Capintec CRC-7, USA), a solid scintillation counter (ORTEC, USA) with a plane (7.62 cm x 7.62 cm) Nal(Tl) detector, an automatic well type gamma counter (Compac-120, Picker, USA) and a multichannel analyser coupled to a Nal(Tl) detector (7.62 cm x 7.62 cm) were used. 

Microanalytical methods for BRs have also been developed (i) gas chromatography/ mass spectrometry (GC/MS) analysis of BRs as bismethaneboronate (BMB) derivatives (72) or methaneboronate-trimethylsilyl (MB-TMS) derivatives (75), (ii) high performance liquid chromatography (HPLC) analysis of BRs as bisboronate derivatives having a fluorophore or an electrophore (14), (iii) Radioimmunoassay (RIA) for BRs (75). Among these microanalytical methods, the GC/MS analysis has greatly contributed to the study on identification and characterization of a number of natural BRs. 

Bahorun and colleagues describe the use of thin-layer chromatography (TLC) to determine total proanthocynidins, phenol, and flavonoid content of hawthorn extracts. High-performance liquid chromatography (HPLC) analysis using a UV detector at 280 nm for proanthocyanidins and phenolic acids, and 360 nm for flavonoids is also described (Bahorun et al., 1996). 

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