Analysis theory of chemical analysis instrument
The principle of correct sample preparation and decomposition of sample preparation is representative. Sample size depends on the total number of samples and the uniformity of its own. Special attention should be paid to some complex samples, such as metal samples to avoid crack porosity, the surface of the sample can not have oil and oxidation. The sample surface has a coating or coating on the basis of the analysis of the requirements to stay within the table or to stay in the table. Due to manufacturing defects cause uneven range of samples can be taken to increase the number of measurements or super large said sample redissolved or by high temperature roasting make it into in crushing oxides dissolve again. High carbon sample drilling to pay attention to the carbon grain collapse, high speed tool steel and other hard samples can be reduced by heat treatment and then sample, etc.. Finally, to ensure the production quantity for a sample analysis of the amount of all times, in order to keep the retest need. Note left on the effect of spectral analysis of surface silicon, aluminum elements with massive sample surface after polishing with sandpaper. Keep the bag of samples, clean and dry, and prevent the sample from deterioration. Sample decomposition mainly considers four aspects:
1, the sample is completely decomposed?
2, the sample in the test component is lost?
3, whether into the interfering substances?
4, the decomposition time is shorter?
The accuracy of the analytical method and the analytical results can be verified and evaluated by using the proper standard substance and the sample operation. Standard material is also the daily analysis of the calibration samples and work standards. Regardless of the purpose of the standard substance used, it is to choose the matrix and the test sample matrix to match the standard material.
When calibration samples are used, the amount of the sample is close to the measured value of the sample, and can be used to make a series of standard material with the component values of the measured value. Using the same analysis method, the same conditions for the analysis of the analysis of standard substance, the measured values by linear regression analysis, linear regression equation including the intercept, slope and correlation coefficient confirmed a linear relation to the specimen was measured value into regression Fang Chengqiu to sample measured components in. This method is frequently used in instrumental analysis. It should be noted that no single standard sample can be used to calibrate the measured sample, because the accuracy of this result cannot be evaluated. In addition, when making the standard curve, people always hope or on the standard curve through the origin, in fact, this is a misunderstanding. The standard curve is linear in a certain concentration range, but the correlation between the response value and the concentration is good, and the other factors are not related to the concentration. Therefore, in many cases the standard curve intercept is not zero is normal.
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