Novel wet digestion method

A new type of wet digestion technology, applied in the preparation of test samples, plastic recycling, recycling technology, etc., can solve the problems of expensive instruments, dangerous high temperature and high pressure environment of microwave digestion instruments, inability to digest with sulfuric acid, etc., to reduce high temperature Risk of high pressure, improving digestion efficiency, preventing ion loss

Pending Publication Date: 2022-07-12
浙江恒祥检测技术服务有限公司
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0004] However, in the existing technology, microwave digestion has a large limit on the sample volume, and the instrument price is relatively expensive. It is not suitable for large-scale heavy metal digestion, and the high-temperature and high-pressure environment of the microwave digestion instrument is relatively dangerous; the traditional wet digestion instrument is cheap, but it is not suitable for sample types. , there are requirements for the type of heavy metal ions. Plastic particles cannot be completely digested only with nitric acid and hydrochloric acid, and the sample contains heavy metal Pb elements. Since lead sulfate is a precipitated substance, it cannot be digested with sulfuric acid.

Method used

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Examples

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Effect test

Embodiment 1

[0024] see figure 1 , the present invention provides a technical scheme: a novel wet digestion method, comprising the following steps:

[0025] Step 1. Plastic sample processing: After the plastic sample is crushed by a rotary pulverizer to a particle size of ≤0.3mm, 20-30 parts by weight of the sample are weighed into the digestion cup. The value during the weighing of the plastic sample is accurate to 0.001g. Put it in an oven to dry at 110 °C for 8 min.

[0026] Step 2. Heating and carbonizing treatment: add 100 parts by weight of concentrated sulfuric acid to the digestion cup, the mass fraction of concentrated sulfuric acid is 1.80-1.84 g / ml, and place it on an electric hot plate at 500°C in a fume hood to heat for 60 minutes, and the carbonization is basically complete. Then a black mixture was obtained. When the concentrated sulfuric acid is added to the digestion cup for carbonization, observe whether white gas escapes during the heating and reflux reaction; if the w...

Embodiment 2

[0030] The novel wet digestion method provided in this example is roughly the same as that in Example 1, and its main difference is:

[0031] In step 2, add 55 parts by weight of concentrated sulfuric acid to the digestion cup, the mass fraction of concentrated sulfuric acid is 1.80-1.84g / ml, and place it on an electric hot plate at 200°C in a fume hood to heat for 30min, and obtain a black color after the basic carbonization is complete. mixture.

Embodiment 3

[0033] The novel wet digestion method provided in this example is roughly the same as that in Example 1, and its main difference is:

[0034] In step 3, the black mixed solution is removed from the top of the electric hot plate, placed in a fume hood to cool for 60 minutes, then 20 parts by weight of concentrated nitric acid is added, the mass fraction of concentrated nitric acid is 1.40-1.44g / ml, and it is placed on the electric hot plate again The carbides in the black mixture were oxidized and reacted for 3 min.

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Abstract

The invention discloses a novel wet digestion method. The method comprises the following steps: S1, treating a plastic sample; s2, heating carbonization treatment; s3, clarification treatment; and S4, preparing an EDTA complex, and preventing precipitation. According to the novel wet digestion method, after concentrated sulfuric acid is added into a sample for carbonization, concentrated nitric acid is added to clarify the carbonized solution, and 50% hydrochloric acid is used for stabilizing metal elements, generating water-soluble EDTA complex metal ions and preventing precipitation, so that the risk of high temperature and high pressure is reduced, and the problem that plastic particles cannot be digested by a common wet method and cannot be degraded is solved. And moreover, ion loss is prevented, the method is suitable for large-scale digestion, and the digestion working efficiency can be greatly improved.

Description

technical field [0001] The invention relates to the technical field of chemical detection, in particular to a novel wet digestion method. Background technique [0002] Plastic materials have the characteristics of easy molding, excellent performance and low price, and are widely used in human life. Especially in the food packaging industry, plastic has become one of the indispensable materials. However, due to the production process, functional modification and other reasons, harmful heavy metals will be introduced, which will endanger people's health and cause environmental pollution to varying degrees. With the gradual improvement of living standards and awareness of food safety, more and more attention has been paid to the safety of food-contactable plastics. The content of heavy metals in plastics has become one of the focuses of human attention. [0003] In the prior art, such as Chinese Patent No.: CN 105044078 A "a method for EDTA-2Na complex digestion and determinat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N1/40G01N1/28G01N1/44
CPCG01N1/4044G01N1/286G01N1/44Y02W30/62
Inventor 金萍陈刚金佳凤
Owner 浙江恒祥检测技术服务有限公司
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