Spectrophotometry measuring method of content of gamma-cyclodextrin (gamma-CD) based on bromocresol green (BCG) developing method

Abstract

The invention discloses a quantitative analysis method of gamma-cyclodextrin (gamma-CD) based on a bromocresol green (BCG) developing method. The measurement method comprises the following experimental steps: (1) a measurement solution is prepared; (2) the light absorption value difference of samples is measured, specifically, a 3 mL of BCG solution with the concentration being 0.35 mmol / L is taken to be added into a 50 mL of brown colorimetric tube, then a 2 mL of gamma-CD solution is added, the constant volume process is conducted to 25 mL through an acetic acid-sodium acetate buffer solution with the pH being being 4.4, after even vibrating, still standing is conducted for 25 min in constant-temperature water bathing at 30 DEG C, then the absorbancy of the gamma-CD solution is measuredwith the buffer solution as the reference at 625 nm, in a blank experiment, 2 mL of distilled water replaces the gamma-CD solution, other experimental operation is the same, and the absorbancy difference (delta A) is equal to the difference between the sample absorbancy (A) and the absorbancy (A') of the blank solution; and (3) a standard curve is drawn, specifically, a 1 mmoL / L gamma-CD solution,a 2 mmoL / L gamma-CD solution, a 3 mmoL / L gamma-CD solution, a 4 mmoL / L gamma-CD solution and a 5 mmoL / L gamma-CD solution are added into tubes correspondingly, the absorption value differences of the1 mmoL / L gamma-CD solution, the 2 mmoL / L gamma-CD solution, the 3 mmoL / L gamma-CD solution, the 4 mmoL / L gamma-CD solution and the 5 mmoL / L gamma-CD solution are measured according to the method, andthen a drawing is made with the concentration of CD as the abscissa and the absorbancy differences (delta A) between the solution of test samples and the blank solution as ordinates to obtain a positive correlation curve as a gamma-CD standard curve.

Description

technical field [0001] The invention relates to a quantitative analysis method of γ-cyclodextrin, in particular to a method for spectrophotometric determination of γ-cyclodextrin content based on the bromocresol green color development method. Background technique [0002] Cyclodextrin (cyclodextrin, referred to as CD) is a cyclic compound obtained by catalyzing starch or its related substances by cyclodextrin glucosyltransferase, the most common ones are α-CD, β-CD, γ-CD 3 species, which are composed of 6, 7, and 8 glucose residues linked by α-1,4 glycosidic bonds. The nature of the hydrophilic outside the CD ring and the hydrophobic inside the ring enables it to form stable complexes with various organic substances and change some properties of organic substances, so it has a wide range of applications in the fields of food, medicine, agriculture, and chemical industry. Among the three kinds of CDs, γ-CD has the largest inner cavity and has a wider ability to embed guest ...

AI Technical Summary

Problems solved by technology

The main shortcomings of the previous test methods are reflected in the following aspects: First, the citric acid buffer system was used in the previous test methods. Due to the large molecular size of citric acid, it is easy to occupy the γ-CD cavity and affect the BCG-(γ-CD) The formation of inclusion complexes affects the accuracy of the (γ-CD) measurement results; secondly, the previous method underestimated the buffer capacity of the measurement solution, resulting in unstable pH values, which easily caused large fluctuations in the measurement results; thirdly, The measurement sampling volume is small, which not only easily causes inconvenient operation, but also easily causes human error, which affects the accuracy and stability of the measurement results

Images