Nitrogen responsive detectors, for

The effort required to establish identity of a nitrosamine in an environmental sample depends on the nature of the problem and the specificity of the primary detection system. TEA response is much stronger evidence of identity than response from a flame ionization or nitrogen-specific detector. If TEA response is supported by chemical (9) or ultraviolet photolysis (8) supporting data, identification is adequate for many... 

Analytical standards are prepared for two purposes for fortifying control matrices to determine the analytical accuracy and for calibrating the response of the analyte in the nitrogen-sensitive detector. 

GC is coupled with many detectors for the analysis of pesticides in wastewater. At the present time the most popular is GC-MS, which will be discussed in more detail later in this section. The flame ionization detector (FID) is another nonselective detector that identifies compounds containing carbon but does not give specific information on chemical structure (but is often used for quantification because of the linear response and sensitivity). Other detectors are specific and only detect certain species or groups of pesticides. They include electron capture,nitrogen-phosphorus, thermionic specific, and flame photometric detectors. The electron capture detector (ECD) is very sensitive to chlorinated organic pesticides, such as the organochlorine compounds (OCs, DDT, dieldrin, etc.). It has a long history of use in many environmental methods,... 

Yan, B. Zhao, J. Leopold, K. Zhang, B. Jiang, G. Structure-Dependent Response of a Chemiluminescence Nitrogen Detector for Organic Compounds with Adjacent Nitrogen Atoms Connected by a Single Bond. Anal. Chem. 2007, 79, 718-726. 

The ECD is well suited as a selective detector for compounds with high electron affinity and limited linear response (dynamic range 104 with nitrogen). ECD detection is mainly used for analyses of chlorine-containing pesticides. Because of the presence of a radioactive source in this detector, it is subject to special regulations (e.g. inspections location and maintenance visits). 

Kelly, T. J. Modifications of Commercial Oxides of Nitrogen Detectors for Improved Response Brookhaven National Laboratory Upton, NY, 1986 BNL Informal Report 38000 pp 1-31. 

Nussbaum MA, Baertschi SW, Jansen PJ. Determination of relative UV response factors for HPLC by use of a chemiluminescent nitrogen-specific detector. J Pharm Biomed Anal 2002 27 983-993. 

At sufficiently high temperatures, the detector also responds to a variety of nitroaro-matics and to (V-nitrosodimethylamine. NOz yields of 0.70 and 0.90 were obtained for 2,4-DNT and TNT, respectively. The detection system exhibits a linear response for all nitrogen-containing compounds studied, and the detection limit for the determination of organic nitrates was found to be 0.05pmol. The relative response factors for aromatic nitro compounds and nitrosamine for the pyrolyser/luminol detector are presented in Table 3. 

Giachetti et al. [60] compared the performance of mass selective detector (MSD), electron capture detector (ECD) and nitrogen-phosphorus detector (NPD) of gas chromatography systems in the assay of six nonsteroidal antiinflammatory drugs in the plasma samples. As a practical test, six NSAIDs (mefenamic, flufenamic, meclofenamic and niflumic acids, diclofenac and clonixin) added to plasma samples were detected and quantified. The analyses were carried out after solvent extraction from an acidic medium and subsequent methylation. The linearity of response was tested for all the detection systems in the range of 1-25 ng/mL. Precision and accuracy were detected at 1, 5 and 10 ng/mL. The minimum quantifiable level for the six drugs was about 1 ng/mL with each of the three detection systems. 

Detectors Flame-ionization detectors are used for most analyses, with lesser use made of thermal conductivity, electron-capture, nitrogen-phosphoms, and mass spectrometric detectors. For quantitative analyses, detectors must have a wide linear dynamic range the response must be directly proportional to the amount of compound present in the detector over a wide range of concentrations. Flame-ionization detectors have a wide linear range ( 106) and are sensitive to organic compounds. Unless otherwise specified in individual monographs, flame-ionization detectors with either helium or nitrogen carrier gas are to be used for packed columns, and helium is used for capillary columns. 

The response of a GC detector can be general or specific. A detector with a catholic response such as the FID is used widely in routine analysis. The specific detector, such as the nitrogen-phosphorus detector (NPD), is extremely useful for measuring particular types of compounds such as herbicides and pesticides, where the compounds of interest are not eluted discretely but mixed with a number of other contaminating compounds. Examples of this type of application will be given when the NPD is discussed in detail. 

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