Thermal energy analyzer chemiluminescent detection with

The oldest chemiluminescent detector was the thermal energy analyzer (TEA), which was specific for N-nitroso compounds. N-nitroso compounds such as nitrosamines are catalytically pyrolyzed and produce nitric oxide which reacts with ozone to produce nitrogen dioxide in the excited ] state, which decays to the ground state with the emission of a photon. A photomultiplier in the reaction chamber measures the emission. Nitrosodi-methylamines have been detected to about 30-40 pg [108]. 

Pfundstein, B., Tricker, A. R., and Preussmann, R., Determination of primary and secondary amines in foodstuffs using gas chromatography and chemiluminescence detection with a modified thermal energy analyzer, J. Chromalogr., 539, 141-148, 1991. 

A sensitive and selective chemiluminescent detector that has made an appreciable impact on the analysis of nitrosamines in environmental samples in the last several years is the thermal energy analyzer or (TEA) (15-19). This detector utilizes an initial pyrolysis reaction that cleaves nitrosamines at the N-NO bond to produce nitric oxide. Although earlier instrumentation involved the use of a catalytic pyrolysis chamber (15,17,19), in current instruments, pyrolysis takes place in a heated quartz tube without a catalyst (20). The nitric oxide is then detected by its chemiluminescent ion react with ozone. The sequence of reactions can be depicted in Figure 1. A schematic of the TEA is shown in Figure 2 (17). Samples are introduced into the pyrolysis chamber by direct injection or by interfacing the detector with a gas chromatograph (15,17,21,22) or a liquid chromatograph (22-25). 

Because of the very high toxicity of NDMA, sensitive analytical methods (suitable for levels in parts per 10 range) have been developed, all involving GC separation. Various mass spectrometric detection strategies have been employed to overcome the problem of possible direet interferences at the low m/z values employed (moleeular mass of NMDA is 74 Da), as described below. Earlier methods (e.g. BUledeau 1987 Tomkins 1995) used GC with detection by the so-called thermal energy analyzer , which is in fact a GC detector based on a chemiluminescent reaction of ozone with nitric oxide (NO) produced... 

The classical nitrosamine analysis was performed for many years by gas chromatography using a thermal energy analyzer (TEA) as detector. This special TEA detector was used due to its selectivity for nitrosamines based on the specific chemiluminescent reaction of ozone with the detector generated NO from nitrosamines. Today, with increased sensitivity requirements, the detection limits of the TEA, and also its complex operation, do not comply any more with the required needs for low detection limits and sample throughput. Mass spectrometric methods have increasingly replaced the TEA. 

---