Spark direct reading spectrometer is a commonly used analytical instrument for determining the content of elements in metal materials. To ensure the accuracy and reliability of its measurement results, it is necessary to validate the results. Here are several commonly used verification methods:

Calibration of standard samples

Using standard samples is one of the commonly used methods to verify the results of spark direct reading spectrometers. A standard sample is a metal block or powder with a known element content, and its composition is accurate and reliable. Before each measurement, place the standard sample into the spectrometer for analysis to obtain the measured value. Then compare the measured value with the standard value of the standard sample and calculate the deviation. If the deviation is within an acceptable range, it indicates that the instrument is in normal working condition and the measurement results are reliable. Generally speaking, for most elements, the deviation should be controlled between ± 1% and ± 3%. If the deviation is too large, it is necessary to inspect and adjust the instrument, such as cleaning the optical system, calibrating the wavelength, etc.

repeatability test

Repetitive testing can evaluate the stability of the results obtained by a spectrometer when measuring the same sample multiple times in a short period of time. Select a uniform sample and measure it continuously multiple times under the same experimental conditions. Calculate the average and relative standard deviation of each measurement result. The smaller the relative standard deviation, the better the repeatability of the instrument. Usually, a relative standard deviation of less than 5% is required. If the repeatability is poor, it may be caused by uneven sample, unstable excitation conditions, or instrument failure, and further investigation and resolution are needed.

Recovery rate experiment

The recovery rate experiment is an important method for verifying the accuracy of spectrometers. Add a certain amount of standard substance to a matrix sample with known content to make a spiked sample. Then measure the content of elements in the matrix sample and the spiked sample separately, and calculate the recovery rate according to the following formula: recovery rate=(spiked sample measurement value - matrix sample measurement value)/standard substance addition amount x 100%. The ideal recovery rate should be between 95% and 105%. If the recovery rate exceeds this range, it indicates that there may be systematic errors in the instrument, and the cause needs to be identified and corrected.

Comparison with other analytical methods

Compare the measurement results of the spark direct reading spectrometer with other mature analytical methods, such as chemical analysis, atomic absorption spectroscopy, etc. If the results of the two methods match well, it indicates that the measurement results of the spectrometer are accurate. This method is particularly suitable for validating newly purchased instruments or instruments that have undergone major repairs.

Daily monitoring

In daily use, it is necessary to regularly maintain and upkeep the spectrometer, such as cleaning the electrodes, replacing argon gas, etc. At the same time, record the sample information, measurement results, and instrument status of each measurement to promptly detect any abnormal situations. If significant deviations or fluctuations are found in the measurement results, the instrument should be checked for faults in a timely manner and corresponding measures should be taken for handling.

Through the comprehensive application of various methods such as standard sample calibration, repeatability testing, recovery rate experiments, comparison with other analytical methods, and daily monitoring, the measurement results of spark direct reading spectrometer can be effectively verified, ensuring the accuracy and reliability of analytical work.