Sensitivity Comparison

7As earlier noted, we refer to the smallest quantity of any given compound that a technology can detect as its LOD. The concept of LOD for mass spectrometery is more rigorously defined in Chapter 11, Section 11.4.3. The concept is used here in a parallel way for the other technologies, without specifying measurement procedures. 

TABLE 1.10 Published or Advertised Limits of Detection for Sensing Technologies 

Lab-on-a-chip/high-performance liquid chromatography 2005 LOC/HPLC 215 Collins, 13.4 

Quadrupole ion trap—time-of-flight mass spectrometer 2005 QitTof MS 0.9 Syage, 11.3.4 

Chemical reagent-based (color change) 2004 Color 1000 [28, p. 42] 

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For sensitivity detection the standard defectometers were used. Relative sensitivity comparison at steel objects radiographic control by radiation with energy of 25 and 45 MeV shows that sensitivity minimum for 45 MeV energy is very displaced towards the big thickness and has not yet reached its minimal meaning at 500mm thickness. 

Fig. 2.6.4 Sensitivity comparison between direct (a) and remote detection (b). With direct detection, an FID is recorded transiently with M data points, which are marked with the symbols x in the first FID in (a). Remotely, M encoding steps are necessary to obtain the same data set, which allows one to perform M signal averaging steps in the direct dimension in the same time. The encoding and detection steps in the remote experiment are intermingled, therefore only a time overhead correspon-...

FIGURE 7.10 Sensitivity comparison of HPLC and UPLC. The same sample was injected twice once using HPLC/MS/MS and again on a UPLC/MS/MS system (A) response for diphenhydramine on each system (B) response of ibuprofen. (Source Adapted from Yu, K. et al., Rapid Commun. Mass Spectrom., 2006, 20, 544. With permission of John Wiley Sons.)... 

Because sensitivity depends on so many different experimental factors, NMR spectroscopists generally use the signal-to-noise ratio, SIN, as a figure of merit for sensitivity comparisons. For example, in a comparison between NMR probes or spectrometers from two vendors, the spectral SIN measured for a standard sample acquired with specified acquisition parameters and probe geometry would provide a direct indication of relative sensitivity. The SIN is calculated for an NMR experiment as the peak signal divided by the root mean square (RMS) noise, given by Equation 7.6, and is directly related to the performance of the radiofrequency coil [3,6]... 

As described in Section 7.4.2, one of the challenges of online LC-NMR is the need to match the chromatographic peak to the active volume of the CapNMR flow cell. An excellent discussion of the comparison of CapLC-NMR with other NMR probe types has been provided by Lewis et al. [17] Table 7.1 shows the sensitivity comparison of the CapNMR probe with larger volume probes. It is important to note that the experimental design used by these authors adjusted the concentration of analyte such... 

Table II. Analytical Sensitivity Comparisons for a 2-ng/cm2 Detectable Limit...

D.Bezier, "Methodes Modemes d Analyse Quantitative Min rale, Masson Cie, Paris(1955) l6)W.W.Meinke, Science 121, 177-84(1955) and Rus translation by N.G. Polianskii, UspekhiKhimii 15,770-80(1956) (Trace element sensitivity , comparison of activation analysis with other methods) 17)G.Charlot D.Bezier, "Quantitative Inorganic Analysis, translated from the French by R.GMurray, Methuen Co, London (19 57), 295 9 18)L.Meites, H.C.Thomas R.P.Bauman "Advanced Analytical Chemistry, McGraw-Hill,NY( 1958), 344-69 19)... 

The utility of UPLC has been demonstrated for both qualitative and quantitative analyses. In 2005, Castro-Perez et al. (2005) compared the performance of a HPLC with that of a UPLC and showed that improved chromatographic resolution and peak capacity attained with UPLC lead to reduction in ion suppression and increased MS sensitivity. Comparison of the mass spectrum obtained using HPLC with that from UPLC (Fig. 1.15) revealed that the higher resolving power of the UPLC-MS system resulted in a much cleaner mass spectrum than that obtained using the HPLC-MS system. The sensitivity improvement directly resulted in a higher ion count in the UPLC mass spectrum (855 vs. 176). 

Chial, B.Z., Persoone, G. and Blaise, C. (2003) Cyst-based toxicity tests. XVIII. Application of ostracodtoxkit microbiotest in a bioremediation project of oil-contaminated sediments Sensitivity comparison with Hyalella azteca solid-phase assay, Environmental Toxicology 18 (5), 279 - 283. 

Lucivjanskd, V., Lucivjanska, M. and Cizek, V. (2000) Sensitivity comparison of the ISO Daphnia and algal test procedures with Toxkit microbiotests, in G. Persoone, C. Janssen and W.M. De Coen (eds.), New Microbiotests for Routine Toxicity Screening and Biomonitoring, Kluwer Academic/Plenum Publishers, New York, pp. 243-246. 

Matin, S.B. and Rowland, M., Electron-capture sensitivity comparison of various derivatives of primary and secondary amines, J. Pharm. Sci., 61, 1235, 1972. 

Notches act as stress raisers and redistribute the applied stress so as to favor brittle fracture over plastic flow. Some polymers are much more notch sensitive than others, but the brittleness temperature depends in general on the test specimen width and notch radius. Polymers with low Poisson ratios tend to be notch sensitive. Comparisons of impact strengths of unnotched and notched specimens are often used as indicators ofthe relative danger of service failures with complicated articles made from notch sensitive materials. 

Homola, J., Koudela, I., and Yee, S. S. (1999). Surface Plasmon resonance sensor based on diffraction gratings and prism couplers sensitivity comparison. Sens. Actuators B 54 16-24. 

Although there are reservations about using Microtox as the primary test in the USA, it is considered useful in species sensitivity comparisons (Ankley et al., 1990, 1992 Bleckmann et al., 1996 Gupta and Karuppiah, 1996a,b). The Microtox test is sensitive to certain toxicants but relatively insensitive to other toxicants, including ammonia. Ammonia is a common toxicant in water and sediment samples (Schot et al., 1995). Microtox often fails to identify ammonia as the toxicant at concentrations toxic to most other aquatic organisms. As a result, when Microtox is used in combination with other species tests, its relative insensitivity to ammonia may lead to results that provide information on toxicants that may be masked by ammonia when only traditional species are used. 

Homola J, Koudela I, Yee SS, Surface plasmon resonance sensors based on diffraction gratings and prism couplers Sensitivity comparison, Sensor Actual. B Chem. 1999 54 16-24. 

Figure 3.12 Sensitivity comparison of UPLC vs HPLC. Same sample (lOng/mL in rat plasma) was injected twice, once for HPLC/MS/MS (3.5 pm particles) and once for UPLC/MS/MS (1.7 pm particles) both columns were 2.1 x 50mm. Examples shown are for diphenhydramine (ESI+, left) and ibuprofen (ESI, right). Reproduced from Yu Rapid Commun. Mass Spectrom. (2006) 20,...

MIO - W. W. Melnke, "Trace Element Sensitivity. Comparison of Activation Analysis With Other Methods", Science 121, 177 (1955).. 

FIGURE 4 Sensitivity comparison between different detection procedures on 10% SDS-gels. (A) Coomassie blue staining. (B) Radioactivation procedure. Lanes 1-7 400 ng of ovalbumin (internal standard) in each track (O) and 400 ng, 40 ng, 4 ng, 400 pg, 40 pg, 4 pg, and 400 fg of BSA (B). Reprinted, with permission, from Wallace and Saluz (1992b). Copyright Macmillan Magazines Ltd., 1992. 

Table 19.4 Sensitivity comparison between textile heat fluxmeters and reference heat fluxmeters for subtractive method... 

Table 19.5 Sensitivity comparison between subtractive method and additive method for small-sized textile heat fluxmeters (same number of thermocouples)...

In order to compare the subtractive method with the additive method (cf. Fig. 19.10), three THFs were produced with the additive method and small sizes (2x2 cm), ie, PES/CO2—A (S), PES/CO3 A (S), and PES3 A (S). Sensitivity comparison between subtractive method and additive method is presented in Table 19.5. 

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