High detection sensitivity

Figure 7b also illustrates the high detection sensitivity of the FTMS instrument. We calculate that the CO peak corresponds to approximately 5000 ions in the analyzer cell. In Figure 7a, the number of ions with m/z 43 was calculated to be approximately 20 million. A point to note is that In FTMS the sensitivity increases with resolution whereas it decreases with other mass spectroscopies. 

Reaction detectors are a convenient means of performing online postcolumn derivatization in HPLC. The derivative reaction is performed after the separation of the sample by the column and prior to detection in a continuous reactor. The mobile phase flow is not interrupted during the analysis and reaction, although it may be augmented by the addition of a secondary solvent to aid the reaction or to conform to the requirements of the detector. Reaction detectors are finding increasing application for the analysis of trace components in complex matrices where both high detection sensitivity and selectivity are needed. Many suitable reaction techniques have been published for this purpose [641-650]. 

REMPI provides high detection sensitivity for free radicals similar to that of LIF.4 In the REMPI method, one or more photons typically from a focused laser radiation initially excite the free radicals to an intermediate excited electronic state. The radicals are further excited and ionized by another photon in the same laser pulse (one-color REMPI) or by a photon of different wavelength from another laser beam overlapping in space and time... 

Some empirical observations can reduce the number of experimental factors that must be investigated. CL reactions require low or medium dispersion to achieve high detection sensitivity. Hence since the predominant feature is the... 

Fluorescence probes combine the advantage of high detection sensitivity with the... 

Molar absorption coefficients should be large enough to allow high detection sensitivity. 

Figure 9-1 Schematic diagram of a gas-liquid chromatography apparatus. The detector is arranged to measure the difference in some property of the carrier gas alone versus the carrier gas plus effluent sample at the exit. Differences in thermal conductivity are particularly easy to measure and give reasonably high detection sensitivities.

Figure 9-49 Proton nmr spectrum at 60 MHz of trichloromethane taken with high-detection sensitivity. See Exercise 9-41.

Silylene SiH2 was directly detected during the pyrolytic decomposition of silane (and ethylsilane EtSiII3) for the first time by intracavity laser spectroscopy in 198865. The high detection sensitivity of this experiment allowed the pyrolysis mechanism to be examined under conditions that optimized film growth rather than spectroscopic conditions. 

We explored the detection and quantification of specific functional groups in proteins using quantitative specific chemical modifications that contain elements with high detection sensitivity. Fluorine was introduced specifically into Bovine Serum Albumin (BSA) by N-trifluoracetylation of the e-amino group of lysine using ethyl thiotrifluoracetate (47). The fluorine electron spectrum from N-trifluoracetylated BSA is shown in Figure 18. 

Laser-Fluorescence techniques for NO are of interest for studying the mechanisms of NO formation and its influence on chemical processes and pollutant formation in flames. In general, the optical fluorescence techniques provide very high detection sensitivities and good spatial resolution. 

Analogous to the majority of dihydropyridines, nifedipine s, nitrendipine s, and nimodipine s chemical structures - a 2- or 3-nitrophenyl substituent in the 4-position combined with the dihydropyridine diester structure - results in a high response in electron capture detection (ECD), thus allowing high detection sensitivity and sufficient assay specificity towards endogenous compounds, metabolites or common co-medications (Muck et al. 1994). 

This technique has proven to be a powerful separation technique for the separation of macromolecules, such as antibodies, for two reasons the near flat plug flow profile and the small diffusion constant of the antibodies. These characteristics eliminate band broadening. With both superior separation power and high detection sensitivity, capillary electrophoresis (CE) can separate free Ab and Ag from bound Ab and Ag rapidly and is suitable for immunoassays. CE can combine immunologic recognition with on-line quantitation, microscale... 

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