Analytical method for measuring content of soluble lead in domestic ceramic

Abstract

The invention discloses an analytical method for measuring content of soluble lead in domestic ceramic. The analytical method comprises the following steps: cleaning a domestic ceramic sample to be measured, naturally airing, dipping a cotton swab in a special kit into a cleaning agent to scrub the surface of the domestic ceramic sample back and forth for 30 s, putting the cotton swab onto a color test paper board, dripping a drop of a color developing agent onto the color test paper board, standing for 2 min, contrasting the color test paper board and a standard operation color level contrast card under the condition of bright light, and determining result range of soluble lead content in the sample by a visual colorimetric method. In comparison with the prior art, the invention has the following advantages: detection limit of lead is 20 ng; the whole analytical testing process lasts for 5-10 min; analytical time is greatly shortened; and work efficiency is raised. Fitting curve regression coefficient of lead dissolving-out amount-scrubbing amount is greater than 0.99, which shows that it is feasible to speculate dissolving-out amount by measuring the scrubbing amount. The method of the invention is simple, fast and easy to operate, and can meet requirements of fast analysis of soluble lead content of domestic ceramic.

Description

technical field [0001] The invention relates to a technique for analyzing soluble elements of daily-use ceramics, in particular to an analysis method for determining the content of soluble lead in daily-use ceramics. Background technique [0002] Daily-use ceramics are indispensable daily necessities in daily life. Many people choose daily-use ceramics decorated with beautiful glazes to hold food. Compared with the low quality of domestic tableware products, it is the low level of imported products. Failure rate. According to the inspection data statistics of the customs clearance laboratory, the unqualified rate of ceramics, enamel and glass tableware in the past three years is less than 2‰. However, due to the relatively long testing cycle (laboratory testing takes 3 working days), the customs clearance speed of imported products cannot be improved, and the importer may need to pay additional temporary storage fees for goods at the port. [0003] On the one hand, there i...

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Problems solved by technology

In the colorimetric method of lead determination, commonly used chromogenic agents include dithizone, triphenylmethane basic dye method, porphyrin-based chromogenic method, arsenazo-based chromogenic method, although the dithizone method is sensitive, but The testing process requires the use of highly toxic chloroform, which is not conducive to environmental protection; there is a fatal flaw in the porphyrin-based chromogenic method, that is, the wavelength shift of the spectral peak before and after color development is only tens of nanometers (this is due to the porphyrin-based chromogenic method). Chromogenic reagents have no significant changes in their structure before and after binding heavy metal ions), generally speaking, this change cannot be clearly recognized by the naked eye, and it is difficult to apply it to rapid on-site screening. In addition, porphyrin reagents also have The color development speed is slow, and an additional complexing agent needs to be added; the sensitivity of arsenazo color developers is generally an order of magnitude lower than that of basic dyes; among basic triphenylmethane dyes, there are many poor water-soluble color developers. Toner, upon reaction with lead ions, forms small particle precipitates

This is very advantageous in flotation separation in industry, but it is inconvenient in trace detection

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