Method for rapidly detecting pigment green in tea through using laser-Raman spectrum technology

A technology of laser Raman spectroscopy and art green, which is applied in the detection field, can solve the problems of complex analysis steps and cannot solve the qualitative and quantitative problems of art green in tea, and achieve the effect of clear and sharp Raman spectrum peaks

Active Publication Date: 2013-01-23
江苏省理化测试中心
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] There are mainly two types of detection methods for art green in tea found in literature and patents, sensory inspection and detection of heavy metals lead and chromium in tea. These methods cannot give accurate results for the existence of art green, and cannot solve the problem. The Qualitative and Quantitative Problems of Artistic Green in Tea
Moreover, the steps of the analytical method in the prior art are complicated, and all require relatively complicated sample pretreatment.

Method used

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  • Method for rapidly detecting pigment green in tea through using laser-Raman spectrum technology
  • Method for rapidly detecting pigment green in tea through using laser-Raman spectrum technology
  • Method for rapidly detecting pigment green in tea through using laser-Raman spectrum technology

Examples

Experimental program
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Effect test

example 1

[0049] a) Using a ThermoFisher DXR laser micro-Raman spectrometer with an excitation wavelength of 780nm.

[0050] b) Make a Raman spectrum for each component of Art Green. Because art green is made by blending lead chrome yellow and iron blue or phthalocyanine blue, make Raman spectra for various monomers (lead chrome yellow, iron blue, phthalocyanine blue) that make up art green, and find out Their characteristics absorb.

[0051] refer to Figure 1 to Figure 5 , is the Raman spectrum of several lead chrome yellows, in which there are 842(±3cm -1 )cm -1 at the characteristic peak; Image 6 It is the Raman spectrum of phthalocyanine blue, and its characteristic absorption is 1524(±3)cm -1 、1339(±3)cm -1 ; Figure 7 It is the Raman spectrum of iron blue, and its strong characteristic peak is 2150 (± 3cm -1 )cm -1 . It can be seen from the Raman spectra of the monomers (lead chrome yellow, iron blue, phthalocyanine blue) that make up art green that their characteristi...

example 2

[0054] Example 2: Drawing of lead chrome yellow standard curve

[0055] a) Preparation of blank tea leaves: clean and dry green tea was pulverized and passed through a 100-mesh sieve.

[0056] b) Weigh 0.100 g of medium chrome yellow (accuracy 0.0001 g), and 99.90 g (accuracy 0.0001 g) of green tea powder prepared in a), and mix well. The concentration of this standard product is 1000 mg / kg.

[0057] c) Weigh 0.01g, 0.05g, 0.10g, 0.15g, 0.20g, 0.25g, 0.3g of the standard product in b), add the blank tea powder in a) to 10g respectively, and mix well to obtain a concentration of Standard series of 1, 5, 10, 15, 20, 25, 30mg / kg.

[0058] d) Use the blank tea powder in a) as a blank, and measure the Raman intensity with the standard series in c), using a ThermoFisher DXR laser micro-Raman spectrometer with an excitation wavelength of 780nm, and use the quantitative analysis software of the instrument to make a standard curve for the concentration. Such as Figure 9 , it can be...

example 3

[0059] Example 3: Drawing of Iron Blue Standard Curve

[0060] a) Preparation of blank tea leaves: clean and dry green tea was pulverized and passed through a 100-mesh sieve.

[0061] b) Weigh 0.100g (accuracy: 0.0001g) of iron blue, and 99.90g (accuracy: 0.0001g) of green tea powder prepared in a), and mix thoroughly. The concentration of this standard product is 1000mg / kg.

[0062] c) Weigh 0.05g, 0.10g, 0.15g, 0.20g, 0.25g, 0.30, 0.35g of the standard product in b), add the blank tea powder in a) to 10g respectively, and mix well to obtain a concentration of 5mg / kg standard series.

[0063] d) Use the blank tea powder in a) as a blank, and measure the Raman intensity with the standard series in c), using a ThermoFisher DXR laser micro-Raman spectrometer with an excitation wavelength of 780nm, and use the quantitative analysis software of the instrument to make a standard curve for the concentration. Such as Figure 10 , it can be seen that there is a good linear relatio...

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Abstract

The invention discloses a method for rapidly detecting pigment green in tea through uisng a laser-Raman spectrum technology. The method comprises the following steps of: performing laser-Raman spectrum chart scanning on tea to be detected, and generating any one group of the following three groups of absorption peaks: (1) 2150(+ / -3)cm<-1>, 842(+ / -3)cm<-1>, (2) 1524(+ / -3)cm<-1>, 1339(+ / -3)cm<-1>, 842(+ / -3)cm<-1>, and (3) 2150(+ / -3)cm<-1>, 1524(+ / -3)cm<-1>, 1339(+ / -3)cm<-1>, 842(+ / -3)cm<-1>, so as to obtain a qualitative result of pigment green in the tea, wherein when the first group of characteristic peaks occurs, the pigment green is formed by mixing iron blue and lead chromate yellow; when the second group of characteristic peaks occurs, the pigment green is formed by mixing phthalocyanine blue and lead chromate yellow; and when the third group of characteristic peaks occurs, the pigment green is formed by mixing the iron blue, the phthalocyanine blue and the lead chromate yellow. According to the method, the existence of the pigment green in the tea can be accurately, qualitatively and quantitatively determined.

Description

technical field [0001] The invention relates to the technical field of detection, in particular to a method for rapidly detecting art green in tea using laser Raman spectroscopy. Background technique [0002] Art green, also known as lead chrome green, is an industrial pigment. Because of its bright appearance, it is mainly used for coloring industrial products such as paints, coatings, inks and plastics. However, because of its bright color, strong coloring, no peculiar smell, and low price, it is often used by unscrupulous traders for tea dyeing, thereby improving the color of tea, increasing appearance, shoddy, and defrauding consumers. Art green because it contains a lot of lead and chromium, a large amount of intake will cause serious harm to the human body. In December 2008, the Ministry of Health issued the "List of Non-edible Substances That May Be Illegally Added in Food and Food Additives That Are Easily Abuse (First Batch)" (Food Remediation Office [2008] No. 3),...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/65
Inventor 李新丽贾涛赵厚民
Owner 江苏省理化测试中心
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