Labelling of chromatograms


The confidence level in the identification capabiUty for gc /ir /ms is enhanced by the abiUty to perform computer Hbrary searching of large spectral databases. Unknown spectra are searched against reference databases and a hit quaUty number, indicating how well the unknown spectmm matches the hbrary spectra, is generated. For the very small peak at 19 min in Figure 4, peak 6 in the TIC, the Hbrary search identified the component as a-pheUandrene [99-83-2] C qH, for both the it and ms data. Because these data are complementary and generated from two completely independent principles of detection, this method provides virtually irrefutable evidence as to a component s correct identity. The complementary nature of the data is further demonstrated by another component in this essential oil. Late in the chromatogram is a long-chain aHphatic alcohol. The mass spectral data confirmed an unsaturated aHphatic chain of specific length, but because of dehydration in the ion source of the ms no alcohol group was evident. On the other hand, the infrared spectmm indicated the presence of an alcohol functionaHty, but gave Htfle evidence with regard to the length of the aHphatic chain. Thus the combination of complementary ir and ms data was the key to the correct identification of this compound.  [c.403]

Figure 13.11 shows the chromatogram obtained for a surface water sample spiked with various chorophenoxy acids at a level of 0.5 p.g 1 under the same conditions as previously and after enrichment on a Cjg column and clean-up on silica SPE cartridges.  [c.353]

If some fields may be empty in the sublevels, all the fields in the main level are required for each entry. A new chiral separation record can be added in CHIRBASE solely if the authors correctly identify both sample and CSP. Since the beginning of the project, our policy has been to contact the authors of all publications containing incomplete, ambiguous or inconsistent data and to ask for additional information. Providing the separations with unique case numbers helps us considerably in this essential task, and also facilitates avoiding redundancies in the database. When chiral separations are reported for the second time in a new publication with exactly the same chromatographic conditions, this is stated in a footnote added in the field comments . In this field, miscellaneous information that cannot appear elsewhere are listed (detection limit, description of a reported chromatogram, racemization study, mobile phase limitations, etc.).  [c.98]


See pages that mention the term Labelling of chromatograms : [c.84]    [c.132]   
Thin-layer chromatography Reagents and detection methods (1990) -- [ c.131 ]