Study On New Methods For The Determination Of Trace Crystal Violet And Leuco Crystal Violet

Chapter1:The significance and headways trend of the health laboratory technologies for crystal violet (CV) and leuco crystal violet (LCV) were introduced respectively. The basic principles for three determination methods of the health laboratory technologies for them were also introduced briefly in this topic.Chapter2:In order to establish a new method for the determination of trace crystal violet in aquatic products by resonance Rayleigh scattering technology, a new associative reaction system of Pb2+-I--CV was selected. In sulfuric acid medium, Pb2+reacted with excessive I-to form a coordination ion [PbI4]2-, then [Pb14]2-reacted with CV cation (CV+) to form an electroneutral ionic associate, which results in increasing of RRS of system. Under the optimal conditions, the enhanced intensity of RRS (Δ/) was linear to the concentration of CV in the range of0.15-180μg·ml-1with correlation coefficient r=0.9993. The detection limit for CV was0.08μg·ml-1and RSD was less than2.5%. The recovery rates were86.4%-107.3%. This method is simple and sensitive. It can be applied to the determination of trace crystal violet in fish samples and fish pond water samples with satisfactory results.Chapter3:In order to establish new methods for the determination of trace crystal violet in aquatic products by fluorescence analysis technology, a new reaction system of CV-NaBH4-SDBS was selected. In pH=8.8Na2B4O7-HCl buffer solution medium, the strong reducing agent NaBH4could quantitatively reaction with CV to form LCV. The LCV can emit fluorescence but was not stable. By addition of surfactant SDBS the fluorescence strength and stability were enhanced. Under the optimal conditions, enhanced intensity of fluorescence (ΔF) was linear to the concentration of CV in the range of2.0×10-7-8.54×10-5mol·L-1with correlation coefficient r=0.9994. A new fluorescence method for the determination of trace crystal violet was established. The detection limit for CV was4.7×10-8mol·L-1and RSD was less than5.12%. The recovery rates were92.2%-117.9%. This method can be applied to the determination of trace crystal violet in shrimp with satisfactory results.Chapter4:A novel fluorescence analysis method was established for the determination of trace leuco crystal violet (LCV). Under the optimal conditions, the enhanced intensity of fluorescence (ΔF) was linear to the concentration of LCV in the range of2.0×10-8-3.75×10-6mol·L-1in weak alkaline acetonitrile medium, with correlation coefficient r=0.9994. The detection limit for CV was1.38×10-8mol·L-1and RSD was less than2.5%. The recovery rates were103.3%-104.9%. This method is simple. It can be applied to the determination of trace crystal violet and LCV in shrimp with satisfactory results. By combination of this chapter and Chapter3, after the determination of the total content (of CV and LCV) in samples and LCV content were determined, respectively, the target of the simultaneous determination of CV and LCV in samples can be achieved.