Development of Trial Chemical Solution Liquefying Silver Methacrylate for Detecting and Measuring Residual Chlorine in Electrolyzed Strongly Acidic Water

Abstract

 Purpose: The solubility of synthesized organometallic compound silver methacrylate in pure water is very low. However, by liquefying silver-methacrylate in an aqueous solution which possesses a hydrophilic group, silver ions can react with even trace amounts of chloride ions to form silver chloride, which is insoluble in water and causes cloudiness. The application of this principle enables the amount of chloride ions in water to be determined. We have developed a new detection solution by synthesizing a particular silver methacrylate compound and adding it to various organic solvents, which can measure the content of chloride ions in electrolyzed strongly acidic water.
 Methods: To develop a system for determining the quantity of residual chloride in water, 0.01, 0.1, and 0.5 wt% silver methacrylate were dissolved in five water-soluble organic solvents (formaldehyde, acetonitrile, N, N-dimethylformamide, lactic acid, and acrylic acid) to produce a detection solution. The solution was poured into electrolyzed strongly acidic water. The acidic water was diluted using ultrapure water 0, 2, 4, 8, 16, 32, and 64 times. We measured the changes in the permeability of its cloudiness, based on the flux of light from an ultraviolet-visible spectrometer after 0, 30, and 60 min (mode:% transmission, 300 nm). The data (%T) were analyzed using four-way analysis of variables (ANOVA; Factor A: solvent, B: silver methacrylate content (wt%, as solute), C: reaction time from flooding, and D: dilution factor of electrolyzed acidic water). We identified the best conditions for practical applications. Next, using the same data, regression analysis was applied to the value of the residual chloride content (ppm) of the electrolyzed water at each dilution factor before flooding with the detection solution, and the corresponding transmission factor (%T) after flooding with the detection solution.
 Results: ANOVA showed significant differences among all the main effects and interactions. In three types of detection solution, the %T values of each acidic water hardly changed for reaction times exceeding 30 min. Additionally, their reactivities with chloride ions were excellent, and the changes in %T corresponded to the dilution factor of the electrolyzed acidic water. Regression analysis was significant in constructing a calibration curve for a detection solution consisting of N, N-dimethylformamide (purity: 99.5%) and 0.01 wt% silver methacrylate, for reaction times of 0, 30, and 60 min. A reaction time of 60 min gave y=−0.081x+97.031 (r=0.9605^**).
 Conclusion: These results show that our detection solution is suitable for practical applications, and can be used to determine the amount of residual chloride in electrolyzed acidic water in dentistry.