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• GC-MS studies to map mechanistic aspects of photolytic decomposition of pesticides

  11-16

  Attila Kiss

  Diána Virág

  Views:

  99

  Transformation of pesticides in the environment is a highly complex process affected by different factors. Both biological and physical-chemical factors may play a role in the degradation, whose ratio depends on the actual environmental conditions.
  Our study aims to reveal specific details of photolytic degradation of pesticides as important soil contaminants. Significance of these studies is enhanced by the fact that pesticide decomposition may contribute to soil degradation, and have harmful biological effects by degrading to toxic products. The toxicity of the examined pesticides is well known, however very little information is available regarding their natural degradation processes, the quality, structure and biological impact of the degradation products.
  The photolytic degradation of frequently applied pesticides of distinctive types (acetochlor – acetanilide, simazine – triazine, chlorpyrifos – organophosphate, carbendazim – benzimidazole) was investigated. A special, immerseable UV-light source was applied in order to carry out photodegradation. The degradation processes were followed by thin layer chromatography (TLC) and mass spectrometry coupled with gas chromatography (GC/MS). EI mass spectrometry was used to identify the degradation species.
  Each of the studied pesticides underwent photolytic decomposition, and the detailed mechanism of photolytic transformation was established. At least four degradation species were detected and identified in each case. Loss of alkyl, alkyloxy, amino-alkyl and chloro groups might be regarded as typical decomposition patterns. Deamination occurred at the last stage of decomposition.

• Wine adulteration and its detection based on the rate and the concentration of free amino acids

  139-151

  János Csapó

  Csilla Albert

  Views:

  365

  Following the definition of wine adulteration, the authors briefly review its history from ancient times to present day and describe the methods that are applied for adulteration of wine from the historical point of view. More space is devoted to the Hungarian wine adulteration and to the detailed reports of the early methods, which attempted to discover fake wine. It describes in detail the current situation of wine adulteration and the fight against counterfeiting. The second half of the review article presents some examples of the analytical chemistry techniques with which fake wines can be detected. In doing so, priority is given to the discussion of high performance liquid chromatography and gas chromatography applications. The end of this paper describes the free amino acid content of wines, and the possibilities of using the results for detection of wine adulteration.