High-performance liquid chromatography equipment

D. Parroitt, Performance verification testing of high performance liquid chromatography equipment, LC-GC, 12(2), 135, 1994. 

A. BenAmotz, Simultaneous profiling and identification of carotenoids, retinols, and tocopherols by high performance liquid chromatography equipped with three-dimensional photodiode array detection, J. Liquid Chromatogr., 18 122 (1995). 

High-performance liquid chromatography equipped with diode array (HPEC-DAD) and electrospray ionization mass spectrometric detection (ESI-MS(n)) has been used to identify anthocyanins in muscadine grapes (Sandhu et ah, 2010). Six different anthocyanin 3,5-diglucosides were identified in muscadine grape skins (Sandhu et al., 2010). 

Hara K, Hijikata Y, Hiraoka E, et al. Measurement of urinary amino acids using high-performance liquid chromatography equipped with a strong cation exchange resin pre-column. Ann Clin Biochem 1999 36 202-6. 

Milbemectin consists of two active ingredients, M.A3 and M.A4. Milbemectin is extracted from plant materials and soils with methanol-water (7 3, v/v). After centrifugation, the extracts obtained are diluted to volume with the extraction solvent in a volumetric flask. Aliquots of the extracts are transferred on to a previously conditioned Cl8 solid-phase extraction (SPE) column. Milbemectin is eluted with methanol after washing the column with aqueous methanol. The eluate is evaporated to dryness and the residual milbemectin is converted to fluorescent anhydride derivatives after treatment with trifluoroacetic anhydride in 0.5 M triethylamine in benzene solution. The anhydride derivatives of M.A3 and M.A4 possess fluorescent sensitivity. The derivatized samples are dissolved in methanol and injected into a high-performance liquid chromatography (HPLC) system equipped with a fluorescence detector for quantitative determination. 

As we have seen so far, libraries of hydrogenation catalysts are never composed of more than a few dozen members, up to 100 to 200 at the most. Consequently, modern analytical equipment such as gas chromatography (GC) or high-performance liquid chromatography (HPLC) equipped with an auto-sampler or even flow-through NMR systems are sufficient to handle the analysis of the entire library. Nevertheless, a few groups have initiated research towards the development of fast, sometimes parallel, analytical procedures. A few reviews have appeared on this subject [59]. Here, we will concentrate on the methods developed to analyze hydrogenation reactions, or methods that could likely be applied. 

Only a few milligrams of sample is needed for a analytic work, and the determination is complete in a few minutes using modem high-pressure, high-speed equipment. The technique is known as high performance liquid chromatography (HPLC). 

For the pharmaceutical scientist, understanding the theory and application of the equipment is usually not sufficient there is the matter of compliance. The qualification of CE is similar to that of other instruments. Installation qualification (IQ), operational qualification (OQ), and performance qualification (PQ) apply in much the same way as high-performance liquid chromatography (HPEC). This chapter details the different parts of the modern CE instrument, equipment-related issues and troubleshooting, instrument qualification, and the future of the CE instrument. 

High-performance liquid chromatography (HPLC) techniques are widely used for separation of phenolic compounds. Both reverse- and normal-phase HPLC methods have been used to separate and quantify PAs but have enjoyed only limited success. In reverse-phase HPLC, PAs smaller than trimers are well separated, while higher oligomers and polymers are co-eluted as a broad unresolved peak [8,13,37]. For our reverse-phase analyses, HPLC separation was achieved using a reverse phase. Cl8, 5 (Jtm 4.6 X 250 mm column (J. T. Baker, http //www.mallbaker.com/). Samples were eluted with a water/acetonitrile gradient, 95 5 to 30 70 in 65 min, at a flow rate of 0.8 mL/min. The water was adjusted with acetic acid to a final concentration of 0.1%. All mass spectra were acquired using a Bruker Esquire LC-MS equipped with an electrospray ionization source in the positive mode. 

The method of complete electrolysis is also important in elucidating the mechanism of an electrode reaction. Usually, the substance under study is completely electrolyzed at a controlled potential and the products are identified and determined by appropriate methods, such as gas chromatography (GC), high-performance liquid chromatography (HPLC), and capillary electrophoresis. In the GC method, the products are often identified and determined by the standard addition method. If the standard addition method is not applicable, however, other identification/determination techniques such as GC-MS should be used. The HPLC method is convenient when the product is thermally unstable or difficult to vaporize. HPLC instruments equipped with a high-sensitivity UV detector are the most popular, but a more sophisticated system like LC-MS may also be employed. In some cases, the products are separated from the solvent-supporting electrolyte system by such processes as vaporization, extraction and precipitation. If the products need to be collected separately, a preparative chromatographic method is use-... 

VAM Instrumentation Working Group, Guidance on the Equipment Qualification of Analytical Instruments High Performance Liquid Chromatography (HPLC), 1998. 

Liquid chromatography is important because most compounds are not sufficiently volatile The first equipment for high-performance liquid for gas chromatography. High-performance liquid chromatography (HPLC) uses high... 

Standard high-performance liquid chromatography (HPLC) equipment with variable-wavelength UV detection... 

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