Mixed indicator, utilization and rapid detection method for grease acid value

A technology of mixing indicators and indicators, which is applied in the direction of material analysis by observing the influence of chemical indicators, and analysis by making materials undergo chemical reactions. There are no problems such as commercialization of the equipment, so as to improve the convenience and speed, reduce the detection error, and realize the effect of safe detection

Inactive Publication Date: 2015-02-11
WILMAR SHANGHAI BIOTECH RES & DEV CENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] (1) It is difficult to distinguish the slight change of the color of the indicator, which leads to large measurement errors, especially in oils with darker or turbid colors, and the difference in the judgment of the endpoint between individuals increases;
[0008] (2) The amount of oil samples required is large, and the neutralization titration takes a long time;
[0009] (3) Most of them need to be carried out in the laboratory, the inspection process is far away from the site, there are many operating links, many chemical reagents and medicines are required, cumbersome solution preparation, acid-base titration procedures, and troublesome sampling and sample delivery
[0018] CN101097210 discloses an automatic detector of grain and oil acid value, but this equipment is not commercialized at present

Method used

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  • Mixed indicator, utilization and rapid detection method for grease acid value
  • Mixed indicator, utilization and rapid detection method for grease acid value
  • Mixed indicator, utilization and rapid detection method for grease acid value

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0159] Preparation of raw materials and reagents:

[0160] (1) Prepare solution and indicator

[0161] ① Saturated n-hexane and methanol solution: Pour analytically pure methanol and n-hexane into a separatory funnel respectively, oscillate fully, and let stand to separate layers; take the upper layer as saturated n-hexane solution A, and take the lower layer as saturated methanol solution B, respectively Keep airtight for later use.

[0162] ②Mixture of ethanol and water: mix ethanol (analytical grade) and distilled water at a ratio of 3:2, keep it airtight until use.

[0163] ③Alkaline solution: Add a mixture of ethanol and water to potassium hydroxide, mix well and then calibrate to obtain lye C, its alkali concentration value (0.03289moL / L), and store it in the dark until use.

[0164] ④Indicator: mixed indicator seven (30mg bromothymol blue + 20mg methyl red + 40mg phenolphthalein) was mixed with 20ml of ethanol and water, sealed and kept until use.

[0165] (2) Prepar...

Embodiment 2

[0173] (1) Decolorization of oil

[0174] Weigh about 200mg of red palm oil, then add 8ml of isopropanol (analytical grade) and about 100mg of activated carbon, heat and reflux for 15 minutes for decolorization, and filter to obtain decolorized solution E.

[0175] (2) Configure solution and indicator

[0176] ① Alkaline solution: Add a mixture of ethanol and water to potassium hydroxide, mix well and calibrate, record the value (0.03289moL / L) and record it as alkali solution C, keep it away from light, and wait for use.

[0177] ②Indicator: Add 20ml of ethanol and water mixture to mixed indicator 8, keep it airtight until use.

[0178] (3). Preparation of standard color chart

[0179] 1. adopt the grease of the standard acid value among the embodiment 1;

[0180] ② Accurately pipette 4ml of the decolorized solution → add 470ul of alkaline solution C and 120ul of mixed indicator V → shake well and oscillate → the result of color development is used as a standard color card....

Embodiment 3

[0190] Example 3: (the operation method is the same as in Example 1, but the amount of lye added is different, and the standard acid value oil used in the preparation of the color chart is 12-16):

[0191] Weigh about 100mg of red palm oil 4→add 4ml solution A to dissolve→accurately add 760ul alkali solution C and shake well→add 4ml solution B for extraction→add 120ul mixed indicator 9 for color reaction→the following layer The color development result of the solution is compared with the standard color card, and the read acid value is 14-15, and the detection result is close to the true value.

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Abstract

The invention provides a mixed indicator. The indicator component of the mixed indicator provided by the invention is basically composed of bromothymol blue, methyl red and phenolphthalein. Detection of grease acid value with the mixed indicator provided by the invention has the characteristics of: convenience and speediness, and high stability detection result. Distinguishing can be realized easily only by visual inspection; operation can be carried out of a laboratory, and the detection process requires only a small amount of organic solvents, thus facilitating detection of a large number of samples. The mixed indicator can be used for dark color grease detection.

Description

technical field [0001] The invention relates to a mixed indicator and a method for detecting acid value, in particular to a method for rapidly detecting the acid value of oils and fats by using a mixed indicator. Background technique [0002] Acid value is a sign of free fatty acid content in fat. During long-term storage, fat is slowly hydrolyzed by microorganisms, enzymes and heat to produce free fatty acid. The quality of fat is related to the content of free fatty acids in it. The acid value is generally used as one of the measuring standards. The acid value can be used as an indicator of the degree of hydrolysis under the conditions of fat production and as an indicator of rancidity under the conditions of its preservation. The smaller the acid value, the better the oil quality, the better the freshness and refining degree. [0003] Its size is an important indicator to measure the quality of crude oil, and it is a key transaction indicator in the trade and circulati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78
Inventor 杨虹顾敏周川姜元荣
Owner WILMAR SHANGHAI BIOTECH RES & DEV CENT
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