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PDA analysis

Fig. 39.3 LC PDA analysis, UV (297 nm) trace (using 1 mL/min gradient elution from 90% H20/MeCN (0.01% TFA) to MeCN (0.01% TFA) over 30 minutes followed by a 5 minute flush with MeCN on a Phenomenex Onyx CiglOO x 4.6mm column) showing a) non-polar, b) intermediate, c) polar fractions and d) characteristic absorbance profile of parotoid secretion from B. marinus. Fig. 39.3 LC PDA analysis, UV (297 nm) trace (using 1 mL/min gradient elution from 90% H20/MeCN (0.01% TFA) to MeCN (0.01% TFA) over 30 minutes followed by a 5 minute flush with MeCN on a Phenomenex Onyx CiglOO x 4.6mm column) showing a) non-polar, b) intermediate, c) polar fractions and d) characteristic absorbance profile of parotoid secretion from B. marinus.
The data presented show a limitation of HPLC-PDA analysis for trace amonnts of CYL in enviromnental samples but also underline the potential of an inexpensive and fast analysis for various purposes. [Pg.266]

Fig. 32.11 Graph showing the results of a PDA analysis of an electrospray produced by Heptane (Reprinted with permission [11])... Fig. 32.11 Graph showing the results of a PDA analysis of an electrospray produced by Heptane (Reprinted with permission [11])...
PDA analysis was also applied to the study of ribonuclease A in reversed-phase chromatography [33]. Ribonuclease A conformation has been the focus of numerous studies, and its dcnaturation is an excellent example of a reversible unfolding process. Cohen et al. [31] first reported the influence of a hydrophobic stationary phase on ribonuclease dcnaturation. In this work, the change in the 254/280 nm absorbance ratio was followed using multiple injections of the same sample. The increase in the ratio correlated extremely well with a number of other physical measurements of structural changes such as circular dichroism and intrinsic viscosity. [Pg.757]

A more recent publication demonstrating the power of PDA analysis for conformational studies focused on the stability of closely related proteins [35]. Using lysozyme as a model protein for showing the influence of protein conformation on the experimentally determined r value (Fig. 6), the second-derivative spectroscopy then provided a straightforward means of comparing the... [Pg.757]

Solvent — The transition energy responsible for the main absorption band is dependent on the refractive index of the solvent, the transition energy being lower as the refractive index of the solvent increases. In other words, the values are similar in petroleum ether, hexane, and diethyl ether and much higher in benzene, toluene, and chlorinated solvents. Therefore, for comparison of the UV-Vis spectrum features, the same solvent should be used to obtain all carotenoid data. In addition, because of this solvent effect, special care should be taken when information about a chromophore is taken from a UV-Vis spectrum measured online by a PDA detector during HPLC analysis. [Pg.467]

US PDA, Guidehne for Approval of a Method of Analysis for Residues, US Department of Health and Human Services, Public Health Service, Food and Drug Adminstration, Center for Veterinary Medicine, Washington, DC (2001). Also available on the World Wide Web http //www.fda.gov/cvin/guidance/guideline3pt5.html. [Pg.324]

The final step of method development is validation of the HPLC method. Optimisation of chromatographic selectivity [110], performance verification testing of HPLC equipment [591], validation of computerised LC systems [592] and validation of analysis results using HPLC-PDA [34] were reported. The feasibility of automated validation of HPLC methods has been demonstrated [593]. Interlaboratory transfer of HPLC methods has been described [594]. [Pg.245]

Aromatic amines formed from the reduction of azo colorants in toy products were analysed by means of HPLC-PDA [703], Drews et al. [704] have applied HPLC/ELSD and UV/VIS detection for quantifying SFE and ASE extracts of butyl stearate finish on various commercial yarns. From the calibrated ELSD response the total extract (finish and polyester trimer) is obtained and from the UV/VIS response the trimer only. Representative SFE-ELSD/UV finish analysis data compare satisfactorily to their corresponding SFE gravimetric weight recovery results. GC, HPLC and SEC are also used for characterisation of low-MW compounds (e.g. curing agents, plasticisers, by-products of curing reactions) in epoxy resin adhesives. [Pg.251]

On-line SFE-pSFC-FTD, using formic or acetic acid modified CO2 as an extraction solvent, was used to analyse a dialkyltin mercaptide stabiliser in rigid PVC (Geon 87444) [114]. Hunt et al. [115] reported off-line SFE-pSFC-UV analysis of PVC/(DIOP, chlorinated PE wax, Topanol CA), using methanol as a modifier. Individual additives are unevenly extracted at lower pressures and temperatures, where extraction is incomplete. Topanol CA, the most polar of the three PVC additives studied, could not be fully extracted in the time-scale required (15-20min), even at the highest CO2 temperature and pressure obtainable. However, methanol-modified CO2 enhances extraction of Topanol CA. PVC film additives (DEHP, fatty acids, saturated and aromatic hydrocarbons) were also separated by off-line SFE-preparative SFC, and analysed by PDA and IR [116]. [Pg.443]

GC-AAS has found late acceptance because of the relatively low sensitivity of the flame graphite furnaces have also been proposed as detectors. The quartz tube atomiser (QTA) [186], in particular the version heated with a hydrogen-oxygen flame (QF), is particularly effective [187] and is used nowadays almost exclusively for GC-AAS. The major problem associated with coupling of GC with AAS is the limited volume of measurement solution that can be injected on to the column (about 100 xL). Virtually no GC-AAS applications have been reported. As for GC-plasma source techniques for element-selective detection, GC-ICP-MS and GC-MIP-AES dominate for organometallic analysis and are complementary to PDA, FTIR and MS analysis for structural elucidation of unknowns. Only a few industrial laboratories are active in this field for the purpose of polymer/additive analysis. GC-AES is generally the most helpful for the identification of additives on the basis of elemental detection, but applications are limited mainly to tin compounds as PVC stabilisers. [Pg.456]

Capillary HPLC-MS has been reported as a confirmatory tool for the analysis of synthetic dyes [585], but has not been considered as a general means for structural information (degradant identification, structural elucidation or unequivocal confirmation) positive identification of minor components (trace component MW, degradation products and by-products, structural information, thermolabile components) or identification of degradation components (MW even at 0.01 % level, simultaneous mass and retention time data, more specific and much higher resolution than PDA). Successful application of LC-MS for additive verification purposes relies heavily and depends greatly on the quality of a MS library. Meanwhile, MB, DLI, CF-FAB, and TSP interfaces belong to history [440]. [Pg.513]

HPLC-PDA-MS) are already being used. Although HPLC-NMR-MS provides a very powerful approach for compositional and structural analysis, it by no means represents the limit of what is possible in terms of hyphenation. On-line extraction and the attachment of multiple detectors (e.g. IR, F) make the technique even more powerful. Other analytical laboratories such as TG-DTA-DSC-FTIR, TD-CT/Py/GC-MS/FTIR and HPLC-UV/NMR/IR/MS have been put to work, but do not represent practical solutions for routine polymer/additive analysis. [Pg.736]

D1 (10,17S-docosatriene) from DHA using tandem liquid chromatography-photodiode array-electrospray ionization-tandem mass spectrometry (LC-PDA-ESI-MS-MS)-based lipidomic analysis have been documented in ischemic brain [4] and retinal pigment epithelium [5], This new lipid is called neuroprotectin D1 (1) because of its neuro-protectiveproperties in brain ischemia-reperfusion [4] and in oxidative stress-challenged retinal pigment epithelial cells [5] (2) because of its potent ability to inactivate proapoptotic signaling (see apoptosis, Ch. 35) [5] and (3) because it is the first identified neuroprotective mediator derived from DHA. [Pg.577]

HPLC/PDA/MS analysis of an alfalfa root extract. The HPLC retention time, the UV absorbance spectrum, and the mass spectrum readily identify the peak eluting at 45 minutes as medicarpin, a known phytoalexin in alfalfa. [Pg.43]


See other pages where PDA analysis is mentioned: [Pg.695]    [Pg.769]    [Pg.36]    [Pg.695]    [Pg.769]    [Pg.36]    [Pg.446]    [Pg.437]    [Pg.456]    [Pg.431]    [Pg.433]    [Pg.437]    [Pg.441]    [Pg.44]    [Pg.45]    [Pg.122]    [Pg.233]    [Pg.242]    [Pg.243]    [Pg.245]    [Pg.247]    [Pg.247]    [Pg.251]    [Pg.269]    [Pg.269]    [Pg.304]    [Pg.515]    [Pg.516]    [Pg.733]    [Pg.733]    [Pg.745]    [Pg.769]    [Pg.26]    [Pg.27]    [Pg.820]    [Pg.587]    [Pg.588]    [Pg.125]    [Pg.125]   
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