Pretreatment method for determining of heavy metal in soil

Abstract

The invention discloses a pretreatment method for determining of heavy metal in soil. The pretreatment method includes the following steps that S1, 0.2-0.5 g of a sample is accurately weighed inside a digestion tank, and 8 ml of aqua regia is added for digestion; S2, according to the digestion process, temperature reaches 100 DEG C through 4 minutes of climbing at 1200 W to be kept for 3 minutes; temperature reaches 150 DEG C through 5 minutes of climbing at 1200 W to be kept for 5 minutes; temperature reaches 180 DEG C through 5 minutes of climbing at 1200 W to be kept for 25 minutes; S3, the digested sample obtained through S2 is transferred into a teflon crucible of 50 ml, 5 ml of nitric acid, 5 ml of hydrofluoric acid and 3ml of perchloric acid are added, a cover covers the teflon crucible, then the teflon crucible is placed on an electric hot plate to be heated for about 1 h at medium temperature, and finally the cover is opened; the temperature of the electric hot plate is controlled to be 150 DEG C-200 DEG C, heating is performed continuously to remove silicon, and when thick perchloric acid smoke or about 1 ml of solution remains through heating, the crucible is taken down to be slightly cooled; S4, after S3 is completed, 1 ml of hydrochloric acid is added, soluble residues are dissolved through warming, the total quantity of solution is transferred into a volumetric flask of 50 ml, the volume is metered to a marked line with water after cooling, and even shaking is performed. The pretreatment method has the advantages that the soil sample can be digested completely, and digestion speed can be increased.

Description

technical field [0001] The invention relates to the technical field of environmental monitoring, in particular to a pretreatment method for the determination of heavy metals in soil. Background technique [0002] In the process of determining and analyzing soil heavy metal content by atomic absorption spectrometry, sample pretreatment is the key. There are many pretreatment methods for soil samples, such as wet digestion, microwave digestion and so on. Each of these methods has advantages and disadvantages. Wet digestion is time-consuming and laborious. The same sample needs to be digested repeatedly. Microwave digestion is fast and automatically controlled, but the digestion is often not complete. [0003] So the prior art needs to be improved and developed. Contents of the invention [0004] The technical problem to be solved by the present invention is to provide a pretreatment method for the determination of heavy metals in soil, which can completely digest soil sam...

AI Technical Summary

Problems solved by technology

Wet digestion is time-consuming and laborious. The same sample needs to be digested repeatedly. Microwave digestion is fast and automatically controlled, but the digestion is often not complete.