Method for measuring citric acid concentration and citric acid diagnose reagent kit

A technology of diagnostic kits and determination methods, applied in the determination/inspection of microorganisms, biochemical equipment and methods, color/spectral characteristic measurement, etc. There are problems such as impurities, so that the test results are more reliable, the test cost is low, and the accuracy is high.

Inactive Publication Date: 2007-12-05
SUZHOU ANJ BIOTECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main quality problem found in the random inspection is that the content of calcium citrate is unqualified. In the random inspection, the content of calcium citrate in some food additives exceeds the requirements of national standards, mainly because the conversion of raw material calcium carbonate is not complete, and there are impurities in the finished product.

Method used

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  • Method for measuring citric acid concentration and citric acid diagnose reagent kit
  • Method for measuring citric acid concentration and citric acid diagnose reagent kit

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Embodiment one (single agent)

[0044] Prepare the citric acid diagnostic kit according to the following ingredients and dosage:

[0045] Tris(carboxymethyl)aminomethane-hydrochloric acid buffer 100mmol / L,

[0046] Ammonium sulfate 500mmol / L,

[0047] NADH 0.25mmol / L,

[0048] Coenzyme A 5mmol / L,

[0049] Citric acid synthase 10000U / L,

[0050] Malate dehydrogenase 12000U / L;

[0051]After the reagents are all dissolved and prepared, they are divided into bottles and freeze-dried to make dry powder reagents; before use, add purified water and reconstitute for use.

[0052] Set on the automatic biochemical analyzer: temperature 37°C, reaction time 10 minutes, initial absorbance 1.8±0.7, test main wavelength 340nm, test subwavelength 405nm, volume ratio of measured citric acid sample to reagent is 1:25 , the reaction direction is negative reaction (falling reaction), and the detection time is about 5 minutes.

[0053] After adding the sample and reagent, let them mi...

Embodiment 2

[0054] Embodiment two (two doses)

[0055] Prepare the citric acid diagnostic kit according to the following ingredients and dosage:

[0056] Reagent I——

[0057] Tris(carboxymethyl)aminomethane-hydrochloric acid buffer 100mmol / L,

[0058] Glycerin 50mmol / L,

[0059] Reduced coenzyme 0.25mmol / L,

[0060] Coenzyme A 5mmol / L;

[0061] Reagent II——

[0062] Tris(carboxymethyl)aminomethane-hydrochloric acid buffer 100mmol / L,

[0063] Propylene glycol 500mmol / L,

[0064] NADPH 0.25mmol / L,

[0065] Coenzyme A 5mmol / L,

[0066] Citric acid synthase 10000U / L,

[0067] Malate dehydrogenase 12000U / L.

[0068] After the reagents are all dissolved and prepared, they are divided into bottles to make liquid double reagents, which can be used directly.

[0069] Set on the automatic biochemical analyzer: temperature 37°C, reaction time 10 minutes, initial absorbance 1.8±0.7, test main wavelength 340nm, test secondary wavelength 405nm, the volume ratio of the measured citric acid sa...

Embodiment 3

[0071] Embodiment three (three doses)

[0072] Prepare the citric acid diagnostic kit according to the following ingredients and dosage:

[0073] Reagent I——

[0074] Tris(carboxymethyl)aminomethane-hydrochloric acid buffer 100mmol / L,

[0075] Ethylene glycol 50mmol / L,

[0076] thio-NADH 0.25mmol / L,

[0077] Coenzyme A 5mmol / L;

[0078] Reagent II——

[0079] Tris(carboxymethyl)aminomethane-hydrochloric acid buffer 100mmol / L,

[0080] Ammonium sulfate 500mmol / L,

[0081] Malate dehydrogenase 12000U / L;

[0082] Reagent III——

[0083] Tris(carboxymethyl)aminomethane-hydrochloric acid buffer 100mmol / L,

[0084] Glycerin 500mmol / L,

[0085] Citric acid synthase 10000U / L;

[0086] After all the reagents are dissolved and prepared, they are divided into bottles to make liquid three reagents, which can be used directly.

[0087] When measuring the concentration of citric acid, set it on the automatic biochemical analyzer: temperature 37°C, reaction time 10 minutes, initial...

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Abstract

The invention relates to a kind of enzyme colorimetric method and a method of the coupling method measuring the density of citric acid and a diagnosis reagent box applying the citrate synthetase and coupling malic dehydrogenase enzymatic reaction continues monitoring method / ratio colorimetric method. The reaction of citrate synthetase enzymolysis citric acid generates oxaloacetic acid and then through the effect of coupling malic dehydrogenase at last oxidizes the reduced coenzyme (there is a absorption peak at the site of 340nm) becoming the coenzyme (there is a absorption peak at the site of 340nm) so we can assay the degree / speed of the fall-way absorbance at the place of 340nm. It can measure and calculate the density of citric acid by measuring the degree / speed of the fall-way absorbance at the place of 340nm. The method has high specificity and it is not polluted by the endogenous and exogenous object and the test result is precise and accurate. The invention can get the array result by the ultraviolet / visible light analytic instrument so it is convenience to extend and apply.

Description

technical field [0001] The invention relates to the detection of citric acid concentration in the fields of medicine, food, environment, etc., in particular to a method for measuring the concentration of citric acid by an enzyme colorimetric method and a coupling method, and a citric acid diagnostic kit prepared thereby, belonging to citric acid The technical field of concentration analysis and detection. Background technique [0002] Citric acid is mainly used in the food and beverage industry as sour agent, flavoring agent, preservative, and preservative, and is also used in the preparation of pharmaceutical cooling agents. It is also used as an antioxidant, plasticizer, detergent. [0003] The mandatory national standard GB17203-1998 "Food Additive Calcium Citrate" stipulates that the content of calcium citrate is 98.0-100.5%. The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China organized a national supervision a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/31C12Q1/26C12Q1/00
Inventor 王尔中
Owner SUZHOU ANJ BIOTECHNOLOGY CO LTD
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