Paint plays an irreplaceable role in decoration and protection, but to ensure safe use, accurate detection of lead content becomes critical. SN/T 3377-2012 provides an accurate way to determine the lead content in paint through the semi-quantitative screening method of energy-dispersive X-ray fluorescence spectroscopy.
Experimental principle
This method uses liquid paint as the matrix to prepare lead standard solutions of different concentrations, and establishes a standard curve in an X-ray spectrometer. Using this standard curve, the standard curve method was used to determine the lead content in the liquid paint sample to be tested. In order to ensure accuracy, reagents such as high-grade pure lead nitrate and absolute ethanol are used, and a magnetic stirrer is used to ensure mixing.
Sample preparation
Prepare a lead standard stock solution by weighing a certain amount of lead nitrate, and mix it evenly with the paint matrix under the action of absolute ethanol. Subsequently, this matrix was used to prepare a series of lead standard working solutions with different concentrations.
Determination process
An energy-dispersive X-ray fluorescence spectrometer is used for analysis. By drawing a standard working curve, the lead standard working solution is sequentially injected for measurement. Draw a standard curve with the concentration of lead in the standard working fluid as the ordinate and the corresponding lead characteristic X-ray intensity as the abscissa. Calculate the lead content in the sample to be tested based on the regression parameters.
Result calculation
The lead content in the sample to be tested is calculated through regression parameters to obtain the accurate concentration of lead in the paint.
Experimental results
The lower limit of the determination of lead in paint samples by this method is 5 mg/kg, and in terms of precision, the absolute difference between the two independent test results obtained shall not exceed 20% of the arithmetic mean.
Through this standard, we can accurately and quickly understand the lead content in paint, which provides an effective means to ensure that the use of paint does not bring potential health risks. The introduction of this method not only improves the accuracy of detection, but also provides strong support for quality management in the paint industry.