Chromatography ultra-violet

High Performance Liquid Chromatography Ultra Violet... 

In modern times, most analyses are performed on an analytical instrument for, e.g., gas chromatography (GC), high-performance liquid chromatography (HPLC), ultra-violet/visible (UV) or infrared (IR) spectrophotometry, atomic absorption spectrometry, inductively coupled plasma mass spectrometry (ICP-MS), mass spectrometry. Each of these instruments has a limitation on the amount of an analyte that they can detect. This limitation can be expressed as the IDL, which may be defined as the smallest amount of an analyte that can be reliably detected or differentiated from the background on an instrument. 

The conventional approach to solvent extraction is the batch method. Early work with this method was hampered by the low concentration of the compounds present and the relative insensitivity of the methods of characterization. Thus lipids and hydrocarbons have been separated from seawater by extraction with petroleum ether and ethyl acetate. The fractionation techniques include column and thin-layer chromatography with final characterisation by thin-layer chromatography, infrared, and ultra-violet spectroscopy and gas chromatography. Of these techniques, only gas chromatography is really useful at levels of organic matter present in seawater. With techniques available today such as glass capillary gas chromatography and mass spectrometry, much more information could be extracted from such samples [20]. 

There are numerous properties of materials which can be used as measures of composition, e.g. preferential adsorption of components (as in chromatography), absorption of electromagnetic waves (infra-red, ultra-violet, etc.), refractive index, pH, density, etc. In many cases, however, the property will not give a unique result if there are more than two components, e.g. there may be a number of different compositions of a particular ternary liquid mixture which will have the same refractive index or will exhibit the same infra-red radiation absorption characteristics. Other difficulties can make a particular physical property unsuitable as a measure of composition for a particular system, e.g. the dielectric constant cannot be used if water is present as the dielectric constant of water is very much greater than that of most other liquids. Instruments containing optical systems (e.g. refractometers) and/or electromechanical feedback systems (e.g. some infra-red analysers) can be sensitive to mechanical vibration. In cases where it is not practicable to measure composition directly, then indirect or inferential means of obtaining a measurement which itself is a function of composition may be employed (e.g. the use of boiling temperature in a distillation column as a measure of the liquid composition—see Section 7.3.1). 

DeCleyn and Verzele (3Q.3J-.32) isolated the four possible isomers from piperinic acid irradiated in an ultra-violet reactor, by counter-current distribution and also the piperidides obtained synthetically from the treated piperinic acid by high pressure liquid chromatography (figure 4). The structures of the isomers were derived mainly from NMR data. Their pungency was recorded, but possibly not by rigorous methods (31.32). The results confirmed the observation of Grewe t ail. (29) that piperine is the pungent principle of pepper, and that other isomers have little taste. ... 

Whereas carbonyl chloride itself is very moisture sensitive and requires the corresponding precautions such as efficiently dried glassware and solvents, the Box derivative is very stable and can be analysed by high performance liquid chromatography (HPLC) with ultra violet (UV) detection at 270 nm. Quantification is achieved by the standard addition procedure spiking carbonyl chloride into the test polymer solution. However, since Box is a commercially available chemical, it is advisable to work also with Box standards, especially when the method is used for the first time and when problems are experienced in the HPLC determination or the derivation procedure. The standards of the carbonyl chloride derivative are particularly useful to establish the analytical system and to check linearity of detector response as well as for the recovery check. 

Three types of monitor are important in chromatography of oligonucleotides ultra violet absorption or transmission monitors electrical conductivity monitors radio-activity monitors. 

Thin layer chromatography Thiocarbonylsulfanylpropionic acid Ultra violet spectroscopy 2-Methylpropionamidine dihydrochloride 2,2 -Azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride... 

The oil shale of the Julia Creek deposit has been shown to contain a very complex mixture of vanadium porphyrin compounds. Several groups of compounds were isolated by column chromatography and high pressure liquid chromatography and examined by ultra-violet-visible spectroscopy, insertion probe, fast atom bombardment and field desorption mass spectrometry. These groups of compounds were found to consist of several homologous series, and included some compounds tentatively identified as phylloerythrin and chlorin derivatives. 

Scott, C. D., Analysis of urine for its ultra violet absorbing constituents by high-pressure anion-exchange chromatography. Clin. Chem. 14, 521-528 (1968). 

Jones, D.C. et al., The analysis of beta-agonists by packed-column supercritical fluid chromatography with ultra-violet and atmospheric pressure chemical ionisation mass spectrometric detection, Analyst, 124(6), 827, 1999. 

The photochemical destruction of ortho, meta and para-nitrophenols induced by ultra-violet light illumination of aqueous slurries of titanium dioxide has been monitored by electronic absorption spectroscopy the products are said to have been identified as dihydroxynitrobenzene isomers by coupled gas chromatography-mass spectrometry although no details are supplied. Nitrophenols have also been identified in the fog shrouding the University of Bayreuth. They are presumed to be the products of photochemical nitration and the possible precursors (phenol, cresol and nitrate) were also detected. 

It was indicated that most detectors used in high-pressure liquid chromatography are optical detectors that use ultra violet, visible or laser light sources. It stands to reason that the solvents that can be used as the mobile phase for liquid chromatography must have special properties. The most important properties of the mobile phase for high performance liquid chromatography are ... 

Clement B., Thomas O. Application of ultra-violet spectrophotometry and gel permeation chromatography to the characterization of landfill leachates Source Environmental Technology 16 (4) 1995 367-377. 

France, J. F. and Voorhees, K. J., Capillary supercritical-fluid chromatography with ultra-violet multichannel detection of some pesticides and herbicides, J. High Resolut. Chromatogr. Commun., 11, 692-696, 1988. 

MEASUREMENT METHODS XAD tube methanol high pressure liquid chromatography with ultra violet detection. 

Ito Y, Oka H, Dcai Y, et al.. Application of ion-exchange cleanup in food analysis V. Simultaneous determination of sulphonamide antibacterials in animal liver and kidney using high performance liquid chromatography with ultra violet and mass spectrometric detection, J. Chromatogr. A 2000 898 95-102. 

Svoboda, M. and Vaeik J., Capillary electrophoresis with ultra violet detection some quantitative aspects. Journal of Chromatography A, 1976, 119 539-547. 

In the cases of both diesel and gasoline exhaust the extract was concentrated, chromatographically cleaned, filtered and separated by high pressure liquid chromatography (HPLC) using ultra-violet fluorescence detection. 

Since its introduction at the end of the 1950s, gas chromatography (GC) has developed into a versatile tool in the analysis of natural products. Clear advantages of GC are the high resolution and high sensitivity of the most common detection method, the flame ionization detector (FID), and the fact that the detector response of similar compounds will be about the same, i.e., peak areas may be directly compared for quantification. This is in contrast to high performance liquid chromatography (HPLC), in which the detector response in the most common detection mode, ultra violet (UV)"absorption, may vary widely for different compounds since the molar extinction coefficients can be very different. 

Almost all known physical methods of analysis have been used to study the constitution of phosphorus compounds. Among the most successful and widely used today are (1) XRD, (2) nuclear magnetic resonance spectroscopy (NMR), (3) infra-red spectroscopy (IR) and (4) chromatography. Emission spectra (visible, ultra-violet and x-ray), mass spectra, electron spin resonance (ESR), and radiochemical techniques are, however, becoming increasingly important. Many other techniques have also been employed, but their success in some instances has been limited to very narrow fields of application. Sensitivities and detection limits are often matrix dependent. Some terms which are currently used to represent a selection of available techniques, are listed in Table 14.4. 

Lacroix, C. Cerutti, F. Nouveau, L Menager, S. Lafont, O. Determination of ethambutol in plasma by liquid chromatography and ultra-violet spectrophoto-metric detection. J. Chrom. B Biomed. Appl. 1987, 59 (1), 85-94. 

Dowell, P.S. Simultaneous determination of fentiazac and p-hydroxyfentiazac in plasma by high-performance liquid chromatography with ultra-violet detection. Analyst (London) 1983,108 (1293), 1535-1537. 

U.R. Tjaden, J.P. Langenberg, K. Ensing, W.P. van Bennekom, E.A. de Bruijn and A.T. van Oosterom, Determination of mitomycin C in plasma, serum and urine by high-performance liquid chromatography with ultra-violet and electrochemical detection, J. Chromatogr., 1982, 232, 355-367. 

Shellard, E. j., and M. Z. Alam The quantitative determination of some mitra-gyna oxindole alkaloids after separation by thin layer chromatography. Part IV. Comparison of ultra-violet spectrometry, colorimetry and densitometry as methods for the quantitative determination of oxindole alkaloids in plant material. J. Chromatog. 36, 72 (1968). 

---