Principles of sample pretreatment for heavy metal determination

The sample pretreatment process and testing process are carried out in accordance with the requirements of the standard method.

The determination of heavy metal elements is divided into three processes: sample preparation, digestion and analytical instrument determination, among which the digestion process is the most critical step

(1) Principles of pre-processing

The main purpose of sample pretreatment is to prevent the measured components in the sample from being lost, contaminated and all converted into a form suitable for measurement

(1) Whether the sample should be pre-treated, how to perform pre-treatment, and which method should be used, should be considered according to the shape of the sample, the requirements of the inspection, and the performance of the analytical instrument used

(2) The pre-treatment should be avoided or used as little as possible, in order to reduce the operation steps, accelerate the analysis speed, and also reduce the adverse effects brought by the pre-treatment process, such as the introduction of pollution and the loss of the object to be tested

(3) When processing the sample, the decomposition must be complete without causing the loss of the component to be tested, and the recovery rate of the component to be tested is sufficiently high

(4) The sample cannot be contaminated, and the introduction of components to be tested and interfering substances cannot be minimized or minimized

(5) The consumption of reagents should be reduced as much as possible, and the method should be simple, easy, fast, and less polluting to the environment

(6) If there is a national standard method, try to choose the national standard method for sample pretreatment