High performance liquid chromatography sample preparation

We isolated C7g, Cg2 and Cg4 by high-performance liquid chromatography (the preparation is described in detail elsewhere ). Laser-desorption time-of-flight mass spectra were obtained to confirm the purity of the isolated samples. We used an ArF (193 nm) laser as the desorption light source . Mass spectra for the samples of C78, Cg2 and Cg4 are shown as inserts to Fig. la-c. We measured C NMR spectra of the higher fuiierenes using CS2 as the solvent with Cr(C5H702)3 as a relaxant. 

As a method of research, has been used high-performance liquid chromatography in reversed - phase regime (RP HPLC). The advantage of the present method is the following the additional information about AIST and FAS composition (homologous distribution) simple preparation of samples (dilution of a CS sample of in a mobile phase). 

Herraiz, T., Sample preparation and reversed phase-high performance liquid chromatography analysis of food-derived peptides, Analytica Chimica Acta, 352, 119, 1997. 

Revilla E and Ryan JM. 2000. Analysis of several phenolic compounds with potential antioxidant properties in grape extracts and wines by high-performance liquid chromatography—photodiode array detection without sample preparation. J Chromatogr 881(1-2) 461 169. 

Spectrophotometric determination with 4-hexylresorcinol and a fluorometric method with m-aminophenol are the most commonly used procedures for the determination of acrolein. However, gas chromatography and high-performance liquid chromatography procedures are also used (USEPA 1980 Kissel etal. 1981 Nishikawa and Hayakawa 1986). Acrolein concentrations in rainwater between 4 and 200 pg/L can be measured rapidly (less than 80 min) without interference from related compounds the method involves acrolein bromination and analysis by gas chromatography with electron capture detection (Nishikawa and Hayakawa 1986). Kissel etal. (1981) emphasize that water samples from potential acrolein treatment systems require the use of water from that system in preparing blanks, controls, and standards and that acrolein measurements should be made at the anticipated use concentrations. 

Kato K. et al., 2005. Determination of 16 phthalate metabolites in urine using automated sample preparation and onhne preconcentration/high-performance liquid chromatography/tandem mass spectrometry. Anal Chem 77 2985. 

Lant M.S. and Oxford J., 1987. Automated sample preparation online with thermospray high-performance liquid chromatography-mass spectrometry for the determination of drugs in plasma. J Chromatogr A 394 223. 

Sample preparation for analysis by hyphenated methods requires some additional planning when compared to nonhyphenated methods. All steps, extraction, concentration, and final solvent selection must take into consideration and be compatible with all the components of the hyphenated instrumentation. For gas chromatographic methods, all the components in the mixture must be in the gaseous state. For liquid chromatography (LC) or high-performance liquid chromatography (HPLC), the samples of the analytes of interest can be solids or liquids, neutral or charged molecules, or ions, but they must be in solution. If the follow-on analysis is by MS, then each of the analytes may require a different method of introduction into the MS. Metals and metal ions may be introduced by HPLC if they are in solution but commonly are introduced via AAS or inductively coupled plasma (ICP). Other analytes may be directly introduced from HPLC to MS [2],... 

Raman often is evaluated as an alternative to an existing high performance liquid chromatography (HPLC) method because of its potential to be noninvasive, fast, simple to perform, and solvent-free. Raman was compared to HPLC for the determination of ticlopidine-hydrochloride (TCL) [43], risperidone [44] in film-coated tablets, and medroxyprogesterone acetate (MPA) in 150-mg/mL suspensions (DepoProvera, Pfizer) [45] it was found to have numerous advantages and performance suitable to replace HPLC. In an off-line laboratory study, the relative standard deviation of the measurement of the composition of powder mixtures of two sulfonamides, sulfathiazole and sulfanilamide, was reduced from 10-20% to less than 4% by employing a reusable, easily prepared rotating sample cell [46]. 

In the separation of biomolecules, sample preparation almost always involves the use of one or more pretreatment techniques. With high-performance liquid chromatography (HPLC), no one sample preparation technique can be appHed to all biological samples. Several techiques may be used to prepare the sample for injection. For example, complex samples require some form of preffactionation before analysis, samples that are too dilute for detection require concentration before analysis, samples in an inappropriate or incompatible solvent require buffer exchange before analysis, and samples that contain particulates require filtration before injection into the analytical instrument. 

High-performance liquid chromatography (HPLC), followed by GC/MS, has been used to fractionate and then quantitate the aliphatic and aromatic hydrocarbons present in liquid fuel precursors in order to determine the fuel potential of the compounds. Kerosene had the advantage of not requiring any sample preparation. Other light fuel oils may require the use of methylene chloride as a solvent prior to HPLC analysis (Lamey et al. 1991). The sensitivity, precision, and recovery of this method were not reported. 

In bioanalysis, High-Performance Liquid Chromatography (HPLC) is the analytical technique most frequently used. Often, extended sample preparation is required to make a biological sample (the matrix) suitable for HPLC-analysis. The compound of interest, the analyte, has to be isolated from the matrix as selective and quantitative as possible. The quality of the sample preparation largely determines the quality of the total analysis procedure. In a survey Majors [2] showed that approximately 30% of an error generated during sample analysis was due to sample preparation, which indicates the need for error reduction and quality improvement in sample preparation. 

Figure 3.2 A scientist prepares a high-performance liquid chromatography (HPLC) machine to analyze a blood sample. The results of the test are visualized on the monitor to her right.

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