Method for detecting hexavalent chrome in dyed leather and product

A detection method and technology of hexavalent chromium, which is used in the measurement of color/spectral properties, preparation of samples for testing, etc. problem, to achieve the effect of low cost, high sensitivity and preventing adsorption

Inactive Publication Date: 2008-12-31
牛增元
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The results obtained by the above standard detection methods have been increasingly questioned by people. The biggest reason is that for dyed, especially dark leather samples, the color of the leaching solution interferes with the measurement, which seriously affects the accuracy of the results.
The IUC-18 standard method itself also admits that due to the interference of color, the exact value of the detection limit cannot be given, and the reference value of 3mg / kg is also difficult to achieve; DIN53314 also clearly stipulates that this standard is not suitable for too many dyes, tanning agents too much leather
In order to solve the detection problem of hexavalent chromium content in dark leather, a lot of researches have been done at home and abroad. The main solutions are as follows: ① Extract Cr-HCl complex with organic phase, and then use atomic absorption for determination. The disadvantage of this method is FAAS Cr(VI) and Cr(III) cannot be distinguished; ② capillary electrophoresis, the sensitivity of this method is not as good as UV-VIS method, and it can only measure high content of chromium; ③ ion exchange, in leather dyes, most dyes are water-soluble anions Dye, with Cr 2 o 7 2- With the same charge, effective separation cannot be achieved; ④Decolorization, there have been many studies on adsorption decolorization at home and abroad, but a decolorant that can achieve effective decolorization has not yet been found

Method used

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  • Method for detecting hexavalent chrome in dyed leather and product
  • Method for detecting hexavalent chrome in dyed leather and product
  • Method for detecting hexavalent chrome in dyed leather and product

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] 1.1 Extraction of samples

[0024] Accurately weigh 10 g (accurate to 0.01 g) of the shredded leather sample into a conical flask, add 1 mL of phosphate buffer (pH=9.63, 2 mol / L dipotassium hydrogen phosphate aqueous solution) and 99 mL of water, mix well, After shaking at room temperature for 2 hours, filter with a 0.45 μm filter membrane.

[0025] 1.2 SPE column pretreatment

[0026] Add 4mL sodium citrate saturated solution (chemical modifier) ​​into the graphitized carbon black solid-phase extraction column (abbreviated as SPE), vacuum filter, the vacuum degree does not exceed 20340Pa, when the liquid surface of the remaining sodium citrate saturated solution in the column leaves the When the upper sieve plate is 2-3mm, stop the suction filtration and wait for use.

[0027] 1.3 Decolorization of extract

[0028] Accurately pipette 10 mL of the filtered extract into a 25 mL beaker, add 2 mL of saturated sodium citrate solution, mix well, pour into a solid phase ex...

Embodiment 2

[0047] According to the steps described in Example 1, a detection test was carried out on the extract of an actual leather sample 1# (gray leather). The results are shown in Table 1.

[0048] Using 4mL and 6mL of chemical modifiers to pretreat the graphitized carbon black SPE column, the recoveries can reach 100% and 97.2%, respectively. However, the recovery rate of the graphitized carbon black column pretreated with only 2 mL of chemical modifier is about 95%. It can be seen that no matter for the aqueous solution or the actual leather extract, the graphitized carbon black column is pretreated with 4mL chemical modifier, and the ideal recovery rate can be achieved.

[0049] Table 1 Actual Sample 1# Results

[0050]

Embodiment 3

[0052] Take another actual leather sample 2# (beige leather), according to the steps described in Example 1, add Cr (VI) standard (equivalent to 3mg / kg) in the extract. The graphitized carbon black solid phase extraction column was pretreated with 4mL sodium citrate saturated solution, one part of the extract was directly passed through the column, and the other part was added with 2mL sodium citrate saturated solution and then passed through the column. The recovery results are shown in Table 2.

[0053] Table 2 actual leather sample 2# results

[0054]

[0055] For the actual leather sample 2#, only adding chemical modifier pretreatment on the graphitized carbon black solid phase extraction column can not prevent the adsorption loss of Cr(VI) well during the filtration process, and at the same time add 2mL chemical modification to the extract The recovery rate can be increased from the original 86.4% to 95.1%, and a good recovery result has been obtained.

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Abstract

The invention discloses a method for detecting hexavalent chromium in dyed leather and its products, which comprises the following steps: extracting hexavalent chromium in dyed leather and its products with phosphate buffer solution; The black solid phase extraction column was used to decolorize the above extract; the decolorized extract was reacted with diphenylcarbazide under acidic conditions; the content of hexavalent chromium in it was determined by ultraviolet-visible spectrophotometry. The present invention has the advantages that: the graphitized carbon black solid-phase extraction column can be used to purify the extracts of leather samples of various colors into a clear and colorless solution; a chemical modifier is introduced in the solid-phase extraction column and the extract, and the While not affecting the decolorization function of the graphitized carbon black column, it can effectively prevent the adsorption of hexavalent chromium by the graphitized carbon black solid-phase extraction column, greatly improving the recovery rate; high sensitivity, fast and accurate, simple operation, no expensive equipment, so The need cost is low, which is very beneficial to popularization and application.

Description

technical field [0001] The invention relates to a detection method of hexavalent chromium, in particular to a detection method of hexavalent chromium in dyed leather and its products. Background technique [0002] Chromium salt tanning agents, chromium-containing dyes and auxiliaries often used in the production and processing of leather products lead to some leather products often remaining a small amount of hexavalent chromium Cr(VI). Cr(VI) is a strong oxidant that can cause skin irritation, pain and allergies, and lead to blood diseases. It is carcinogenic at high concentrations and is a heavy metal ion that is quite toxic to the human body and the environment. It has attracted widespread attention from the international community and has Strict controls are in place. In the decree promulgated by the German government, it is included in the list of prohibited dangerous goods, and its detection amount in the final product shall not exceed 3mg / kg (detection limit). , Art...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N21/31G01N1/34
Inventor 牛增元叶曦雯
Owner 牛增元
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