Detectors for evaluation

Analyses were done with a Perkin Elmer Model 900 gas chromatograph equipped with a flame ionization detector. For evaluation of the charcoal the gas chromatograph was fitted with a 3.0-m x 3 2-mm o.d. stainless steel column packed with 10 ... 

Reimer, G.M., 1976. Design and assembly of a portable helium detector for evaluation as a uranium exploration instrument. US Geol. Survey, Open File Report, 76-398,10 pp. 

The principle of headspace sampling is introduced in this experiment using a mixture of methanol, chloroform, 1,2-dichloroethane, 1,1,1-trichloroethane, benzene, toluene, and p-xylene. Directions are given for evaluating the distribution coefficient for the partitioning of a volatile species between the liquid and vapor phase and for its quantitative analysis in the liquid phase. Both packed (OV-101) and capillary (5% phenyl silicone) columns were used. The GG is equipped with a flame ionization detector. 

With the multitude of transducer possibilities in terms of electrode material, electrode number, and cell design, it becomes important to be able to evaluate the performance of an LCEC system in some consistent and meaningful maimer. Two frequently confused and misused terms for evaluation of LCEC systems are sensitivity and detection limit . Sensitivity refers to the ratio of output signal to input analyte amount generally expressed for LCEC as peak current per injected equivalents (nA/neq or nA/nmol). It can also be useful to define the sensitivity in terms of peak area per injected equivalents (coulombs/neq) so that the detector conversion efficiency is obvious. Sensitivity thus refers to the slope of the calibration curve. 

Styring, M. G., Armonas, J. E., and Hamielec, A. E., An experimental evaluation of a new commercial viscometric detector for size-exclusion chromatography (SEC) using linear and branched polymers, /. Liq. Chromatogr, 10, 783, 1987. 

The advent of CCD detectors for X-ray diffraction experiments has raised the possibility of obtaining charge density data sets in a much reduced time compared to that required with traditional point detectors. This opens the door to many more studies and, in particular, comparative studies. In addition, the length of data collection no longer scales with the size of the problem, thus the size of tractable studies has certainly increased but the limit remains unknown. Before embracing this new technology, it is necessary to evaluate the quality of the data obtained and the possible new sources of error. The details of the work summarized below has either been published or submitted for publication elsewhere [1-3]. 

Bhattachar, S.N., Wesley, J.A., and Seadeek, C. 2006. Evaluation of the chemiluminescent nitrogen detector for solubility determinations to support drug discovery. J. Pharm. Biomed. Anal. 41 152. 

Since detectors are by definition exposed to combustible gases they should be rated for electrically classified areas, such as Class I, Division I or 2, the specific gas groups (normally groups C and D), and temperature ratings. It should be noted the UL presently does not specifically test combustible gas detector sensor heads for use in classified areas, although they do tests enclosures for control and data acquisition circuits. Several other international standards do evaluate combustible gas detectors for use in classified areas (e.g., BS 6020). 

LOD and LOQ were measured to assess the sensitivity of the FID, ECD and TSD detectors for GC analysis of various nitroaromatic compounds. A parallel connection of the three detectors at the end of a single narrow-bore capillary column enabled direct comparison of the chromatograms. Structural effects on the response were evaluated and detection mechanisms were discussed. Recommendations were made for identification purposes and for analysis of environmental samples of nitro- and chloro-nitro-benzenes in a wide range of concentrations451. 

A PDA detector provides UV spectra of eluting peaks in addition to monitoring the absorbance of the HPLC eluent like the UVA is absorbance detector. It is the preferred detector for testing impurities and for method development. PDA facilitates peak identification during methods development and peak purity evaluation during method validation. Detector sensitivity was an issue in earlier models but has improved significantly (more than ten-fold) in recent years. ... 

Once it is determined that flammable gas detection is needed for a processing area, an evaluation of the gas/liquid composition of each credible release can be done. The formation and behavior of gas clouds is primarily governed by whether the material is released as a gas or as a liquid. In order to properly locate detectors, the expected behavior of a gas cloud must be understood. Similar considerations apply to the release of toxic materials and the appropriate location of detectors for these materials. 

Chan HK, Carr GP. Evaluation of a photodiode array detector for the verification of peak homogeneity in high-performance liquid-chromatography. Journal of Pharmaceutical and Biomedical Analysis 8, 271-277, 1990. 

Fang LL, Wan M, Pennacchio M, Pan JM. Evaluation of evaporative light-scattering detector for combinatorial library quantitation by reversed phase HPLC. Journal of Combinatorial Chemistry 2, 254-257, 2000. 

An Experinaental Evaluation of a New Commercial Viscometric Detector for Size Exclusion Chromatography... 

Other instruments for evaluation of electron beam process are real-time monitors. They provide a continuous display in real time of dose delivered to product, as well as the energy of the electron beam. Moreover, they can show the variations in dose across a wide web if multiple detectors are installed and provide alarm signals to warn the operator of high- and low-dose conditions, and record the performance of the processor for production control, quality assurance, and maintenance needs. The major advantage of these real-time instruments is that they monitor the current and beam energy independently. ... 

Resolution. System resolution for the 18-cm.3 Ge(Li) detector was evaluated at a bias voltage of 1700 volts. Leakage current was 0.5 X 10"9... 

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