甲醛和八大重金属测试简要步骤

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部分化学测试简要步骤，以下面样品为例：
Simple procedure of some chemical test, take the sample below as an example:

一、    甲醛（HCHO）含量的测试步骤：
Procedure of Formaldehyde (HCHO) analysis:
1.    把样品剪碎如下:
cut two test specimens into small pieces as below:

2.    称取平行样各2g，精确到10mg，并装入250ml的带塞锥形瓶中。
weigh approximately 2 g of the pieces to an accuracy of 10 mg, for each test specimen, put the weighed pieces into a 250 ml flask with a stopper.

3.    在锥形瓶中加入100ml超纯水，放入水浴中。在40℃下震荡1小时
Add 100 ml of water into each flask, stop tightly and place in a water bath at (40 2) °C for (60 5) min. Shake the flask at least every 5 min, ensuring that the specimens are entirely wet.



4.    震荡完毕后，立即取出过滤.
Then filter the solution into another flask through a filter.

5.    将样品溶液和显色剂（纳氏试剂）按1:1的比例混合，摇匀。
Put 5 ml of the filtered test specimen solution in tubes, add 5 ml of acetylacetone reagent into each tube and shake them.

6.    然后放入40℃水浴中避光显色半小时,然后室温中放置半小时。
Keep the test tubes first in a water bath at (40 2) °C for (30 5) min and then at ambient temperature for (30 5) min.


7.    用紫外可见分光光度计,置溶液于10mm的比色皿中，在波长412nm处分析样品的吸光度。
Using the UV-VIS spectrophotometer , measure the absorbances in a 10 mm absorption cell at a wavelength of 412 nm.





二、    八大重金属含量测试步骤：
Procedure of Total Heavy Metal (8 elements) analysis:
1.    称取剪碎的样品0.15g于消解罐中,加入10ml浓硝酸(在通风橱中)，密封。
Weigh a well-mixed sample near 0.15g into an appropriate vessel equipped with a pressure relief mechanism, add 10± 0.1 mL concentrated nitric acid（in a fume hood）, then seal up.

2.    将消解罐放入微波设备中进行消解，过程大概2小时。
Take prepared vessels into microwave system that using microwave heating to digest samples. It will take near 2 hours.

3.    消解完毕冷却后，将样品冲洗定容后，再过滤到小试管中，准备上机。
After cooling, the vessel contents may be filtered, centrifuged, or allowed
to settle and then decanted, diluted to volume.

4.    最后用ICP-OES分析其中重金属的含量
Then analyze the total heavy metals by ICP-OES.

若重金属含量超过限值，则需要做萃取测试，如下：
If the results of total heavy metals exceed the limits, it need to do a migration test.
Below is the procedure of migration test:
1.    称取样品0.2g于50ml的锥形瓶中
Weigh approximately 0.2 g of the pieces into a 25 ml flask.

2.    加入10ml 0.07mol/L的盐酸溶液，在37℃水浴中震荡1小时，再静置1小时
Add 10ml 0,07 mol/l aqueous solution of hydrochloric acid, Agitate the mixture at (37 ±2) °C for 1 h continuously and then allow to stand for 1 h at (37±2) °C.


3.    然后立即取出直接过滤到小试管中准备上机
Without delay, efficiently separate the solids from the solution. The solution be filtered into tubes.

4.    最后用ICP-OES分析其中重金属的含量
Then analyze the heavy metals of migration by ICP-OES.

End

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部分化学测试简要步骤，以下面样品为例：

Brief procedure of some chemical test, takethe sample below as an example:



一、甲醛（HCHO）含量的测试步骤：

Procedureof Formaldehyde (HCHO) analysis:

1. 把样品剪碎如下:

cut two test specimens into small pieces as below:



2. 称取平行样各2g，精确到10mg，并装入250ml的带塞锥形瓶中。

weigh approximately 2 g of the pieces to an accuracy of 10 mg, for eachtest specimen, put the weighed pieces into a 250 ml flask with a stopper.

Add 100 ml of water intoeach flask, stop tightly and place in a water bath at (40 ±2)°C for (60 ± 5) min. Shake the flask at least every 5 min, ensuring that the specimensare entirely wet.

Then filter the solution into another flask through a filter.

Keep the test tubes first in a water bath at (40 ± 2)°C for (30 ± 5) min and then at ambient temperature for (30 ± 5)min.

Using the UV-VIS spectrophotometer , measure the absorbances in a 10 mmabsorption cell at a wavelength of 412 nm.

Weigh a well-mixed sample near 0.15g into an appropriate vesselequipped with a pressure relief mechanism, add 10± 0.1 mL concentrated nitricacid（ina fume hood）,then seal up.

After cooling, the vessel contents may be filtered, centrifuged, orallowed

Add 10ml 0,07 mol/laqueous solution of hydrochloric acid, Agitate the mixture at (37 ±2) °C for 1h continuously and then allow to stand for 1 h at (37±2) °C.

Good demonstration!!