Carbon paste electrode (CPE) was modified with F-300 commercial activated carbon or Norit SX- 2 powdered activated carbon. CPEs were prepared for detection of 2,4-dichlorophenoxyacetic acid (2,4-D), 2,6-dichlorophenoxyacetic acid (2,6-D) and 2,4,6-trichlorophenoxyacetic acid (2,4,6-T). The electrochemical behavior of these materials was investigated employing cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The modifier was found to enhance the electroactive surface area and the peak current in comparison to the bare (unmodified) carbon paste electrode. The intensity of the signal increased with the increase in adsorption ability of the modifiers. Compared to the unmodified electrode, all the new paste electrodes showed a much greater sensitivity for detection of chlorinated phenoxyacetic acids in water samples.
This paper aims at presenting the possibilities of applying gas chromatography for the determination of pharmaceutical residues in different matrices. Section one of the study underscores the environmental advantages of employing GC for such analyses. Section two presents the innovative methods for determining pharmaceuticals in the environment. The last section discusses the results of the analysis of the GC and GC-MS market in Poland. According to the literature data, the described methods were applied for the analysis of real samples: wastewaters, surface waters, soil samples. The samples were collected from the Pomerania region and the Gulf of Gdańsk. The pharmaceuticals were determined in various environmental samples. The highest concentrations were found in raw wastewater, medium – in a treated wastewater, and the lowest – in surface water. The most frequently detected pharmaceuticals were: ibuprofen, paracetamol, diclofenac and naproxen, all belonging to NSAIDs. Furthermore, the results of the study of the Polish GC market indicate that a very limited number of entities are currently using chromatographic techniques, and pharmaceutical residues tests are exceptions, mainly due to the lack of the legal requirements in this field and the lack of own laboratories.