Rapid microwave‐assisted Porter method for determination of proanthocyanidins

Abstract

Introduction Proanthocyanidins have been widely developed and utilised in food, medicine, health care products and cosmetics. Porter‐high‐performance liquid chromatography (HPLC) is a quantitative method often utilised in many fields. This method uses a water bath to reflux the proanthocyanidins, but the process is cumbersome, the reagent consumption is large, and multiple batches of simultaneous treatments cannot be evaluated. Objective To establish a more convenient, rapid and high‐batch processing method for determining the content of proanthocyanidins in functional food by HPLC. Methods N‐Butanol–hydrochloric acid and iron salt are used as the reaction medium in the Porter method. After investigating the optimal conditions, the hydrolysis of proanthocyanidins can be performed in a microwave reactor at a power of 640 W for 75 s in the Porter reaction system. The content of proanthocyanidins was determined by HPLC with external standards. Results After the rapid pretreatment of samples, proanthocyanidins were determined by HPLC with a diode array detector at a detection wavelength of 525 nm with 0.53 μg/mL and 1.61 μg/mL limits of detection and quantification, respectively, for proanthocyanidin ions, and the linearity was 0.9999. Intra‐ and inter‐day relative standard deviation values were between 1.5% and 3.1%, and the recovery was between 91.40% and 107.43% for the determination of different products, such as capsules, tablets and tea, which were similar to the values obtained with the conventional Porter method. Conclusion This method is a time‐saving and low cost approach for quantitative analysis of various proanthocyanidin health products that offers the advantages of high‐batch processing and environmental friendliness.

A thermally reversible injectable adhesive for intestinal tissue repair and anti-postoperative adhesion

“…The experimental steps were based on previous studies with a slight modification. 28 In brief, first, the mixed solution of 2% Fe(NH 4 ) 2 SO 4 solution and 2 mmol l −1 HCL was prepared, and then the above solution was mixed with 1 mol L −1 HCL and n -butanol in a volume ratio of 1 : 6 : 83. This solution was named mixed solution A.…”