Microwave digestion method for the determination of phosphorus / phosphatide content in oil

A technology of phospholipid content and microwave digestion, which is applied in the preparation of test samples, measurement of color/spectral properties, and analysis by chemical reaction of materials, etc., can solve the problems of long ashing time and low detection limit, etc. To facilitate subsequent operations, meet the needs of phospholipid detection, and shorten the analysis time

Inactive Publication Date: 2014-08-06
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The detection limit of this method is low, and the analytical data is accurate and reliable. The obvious disadvantage is that the carbonization and ashing of the sample take a long time, and generally need more than 9 hours to complete.

Method used

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  • Microwave digestion method for the determination of phosphorus / phosphatide content in oil
  • Microwave digestion method for the determination of phosphorus / phosphatide content in oil
  • Microwave digestion method for the determination of phosphorus / phosphatide content in oil

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] precision test

[0024] Weigh 5 samples of Zanthoxylum bungeanum seed oil, put 2.0g each into a polytetrafluoroethylene digestion tank, add 4~8mL of nitric acid and 1~3mL of hydrogen peroxide, shake well, tighten the sealing cap, put the tank into the microwave digestion apparatus, Adjust the power to 800~1000W, and take 7~9min to digest. After the digestion is completed, take out the digestion tank and cool it down, put the digestion solution in a 50m volumetric flask, set volume, and shake well.

[0025] Take the digestion solution in the 10mL volumetric flask and put it in five 50mL volumetric flasks, add 8mL of 0.015% hydrazine sulfate solution and 2mL of ammonium molybdate sulfuric acid solution. Dilute to the mark with deionized water, shake well, and take deionized water as blank at the same time, after standing still for 20min, under the wavelength of 650nm, use Lcm liquid tank to measure its absorbance respectively, and use the standard curve equation to find ...

Embodiment 2

[0029] Recovery test

[0030] Prepare phosphorus standard solutions of three concentrations respectively, add them to soybean oil, measure the phosphorus content therein after mixing, and the operating conditions are the same as the method in Example 1. See Tables 2, 3, and 4 for specific experimental data.

[0031] Table 2 Concentration 1 (phosphorus content about 0.8mg) recovery test results

[0032]

[0033] Table 3 The recovery rate experiment results of concentration 2 (phosphorus content is about 0.4mg)

[0034]

[0035] Table 4 Concentration 3 (phosphorus content about 0.1mg) recovery experimental results

[0036]

[0037] Can illustrate from table 2,3,4, the rate of recovery is between 97.57~101.88%, and the accuracy of the present invention meets detection requirement.

Embodiment 3

[0039] Comparative experiment and comparative experiment of GB5537-2008

[0040] Repeat the above determination according to the GB5537-2008 method, and the specific experimental data are shown in Table 5.

[0041] Table 5GB5537-2008 The recovery rate experiment result of concentration one

[0042]

[0043] The recovery experimental result of table 6GB5537-2008 concentration two

[0044]

[0045] Table 7GB5537-2008 The recovery rate experiment result of concentration three

[0046]

[0047] Table 8 The method and the recovery contrast experiment result of GB5537-2008

[0048]

[0049] It can be shown from the experimental data in Table 8 that the recovery rate measured by the present invention is equivalent to that of GB5537-2008, but its precision is better than the latter at three levels.

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Abstract

The invention relates to a microwave digestion method for the determination of phosphorus / phosphatide content in oil. The method is as below: adding 4-8mL of nitric acid and 1-3mL of hydrogen peroxide into 0.2g of a sample, digesting the sample in a microwave digestion instrument, setting the digestion liquid to a determined volume in a volumetric flask and shaking uniformly; preparing a hydrazine sulfate solution and an ammonium molybdate sulfuric acid solution; drawing a standard curve to form a curve equation; preparing a phosphate standard solution for the standard curve; adding the hydrazine sulfate solution and the ammonium molybdate sulfuric acid solution into the digestion solution in the volumetric flask; diluting with deionized water to the scale, shaking uniformly, standing, and measuring the absorbance at the wave length of 650nm by using deionized water as the blank; and checking the amount of phosphorus from the standard curve according to the absorbance of the measured solution, and calculating the phosphatide content according to a formula as below. According to the method, nitric acid and hydrogen peroxide are added into the sample, which is digested in a micro wave digestion furnace; and the method can substitute a phosphatide dry ashing determination method, and has the advantages of greatly shortened analysis time, direct volume setting of the digestion liquid, convenience for the following operations and accurate and reliable determination results.

Description

field of invention [0001] The invention relates to a method for determining the content of phosphorus / phospholipid in oil by using microwave digestion technology. Background technique [0002] Phospholipids are complex mixtures of glycerol, fatty acids, phosphoric acid, and aminoalcohols that dissolve in oils that contain little water. Oilseeds contain more phospholipids, and phospholipids are easily transferred to oil during oil production. Because phospholipids are hydrophilic, they can increase the moisture content of oils, promote the hydrolysis and rancidity of oils; phospholipids are also emulsifying, and will produce a lot of foam when cooking and heating; at the same time, they are easy to oxidize, and will turn black and bitter when heated, which will affect the quality of fried food . Only by measuring the content of phospholipids can the amount of water added to crude oil in the production process be determined. At the same time, phospholipid itself is an extre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/75G01N21/31G01N1/44
Inventor 崔锡红李建忠何玉莲冯俊王嶙吴琼王桂芝赵光辉董平邓旭亮秦丽华贾云刚何昌洪王东军邵伟白玉洁方磊侯卫东
Owner PETROCHINA CO LTD
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