Soil is an important natural resource for agricultural production and a carrier for plant growth and development to absorb water and mineral nutrients. With the increasing activities of mining, smelting and processing of heavy metals by human beings, soil pollution is increasing. The pollution of heavy metals to the soil will affect the growth and development of plants and reduce the yield and quality of crops. After heavy metals in the soil are absorbed by plants into the food chain, they will further cause serious harm to human health and the ecosystem. Therefore, rapid determination of heavy metal content in soil and timely understanding of soil pollution status have important practical significance for soil quality, environmental assessment and human health.
Sample name: soil sample
Determination of elements: arsenic (As), bismuth (Bi), mercury (Hg), antimony (Sb), selenium (Se)
Digestion reagents: nitric acid AR, hydrochloric acid AR
Instrument configuration: MWD-610-T6 closed intelligent microwave digestion/extraction instrument
Number of samples: 12
Operation process:
Weigh 0.2g (accurate to 0.0001g) of 12 soil samples and place them carefully at the bottom of each inner pot;
Wet the sample at the bottom of the cup with a small amount of experimental water;
In a fume hood, add 2ml of nitric acid and 6ml of hydrochloric acid to the cup respectively, and gently shake the cup to mix the sample and the digestion reagents thoroughly. If there is a violent reaction, let it stand in the open until the end of the reaction.
Seal the tank and load it into TRUMP for digestion reaction. The procedure is as follows
Pressure(0.1MPa) | 5 | 38 |
Temperature(℃) | 120 | 185 |
Power(W) | 1000 | 1000 |
Heating time(s) | 300 | 300 |
Constant temperature time(s) | 60 | 900 |
After the digestion is completed and cooling is over, transfer the digestion tank to a fume hood and let it stand for 10 minutes.
Opening the can: In a fume hood, unscrew the outer tank of the digestion tank, slowly release the pressure in several times, and then take out the inner tank; unscrew and remove the sealing cover of the inner tank. (Note: After operating one set of digestion tanks, open another set of digestion tanks.) Transfer the solution to a volumetric flask, rinse the inner cavity of the cup and the inner cavity of the sealing cap, and combine the rinse solution into the volumetric flask.
Make the volume up to the mark with experimental water, mix well, let it stand for 60 minutes, and take the supernatant for testing.