Preparation And Application Of Test Paper For Rapid Detection Of Reducing Sugar

A quick and accurate method for the determination of content of reducing sugar in food and medicine is very important to improve the food and medicine quality.At present,the chemical analysis method and instrument method were frequently employed due to high precision and good repeatability.Unfortunately,it also existed lots of shortcomings such as tedious steps,expensive price,and high inconvenience.Therefore,the rapid and convenient determination of reducing sugar is still a great challenge.Herein,according to DNS colorimetric,the test paper which could realize rapid detection of reducing sugar was synthesized successfully based on natural fiber.Owe to simple operation,portability,and environmental protection,test paper has the potential to be developed into practical applications.Based on the DNS colorimetric method,solid chromogenic agent was successfully prepared using 3,5-Dinitrosalicylic acid and calcium oxide as raw materials.FT-IR analysis showed that the partial-NO₂ in the benzene ring of 3,5-Dinitrosalicylic acid was reduced to-NH₂ during chromogenic reaction.The calcium oxide was used to provide heat and alkaline environment for color reaction.And the thermal stability of the chromogenic agent with high calcium oxide content is higher than that of low calcium oxide content.When the ratio of 3,5-Dinitrosalicylic acid to calcium oxide is 1:15,the color is clear and the gradient is obvious.Using 3,5-Dinitrosalicylic acid as color reagent,calcium oxide as heat source and filter paper as paper base,test paper for quick measurement of reducing sugar was successfully prepared by soaking,pumping and coated with calcium oxide on both sides.The results show that the optimum paper base is fast qualitative filter paper,and the chromogenic reagent concentration,soaking time of color reagent,drying temperature,and chromogenic time was 6g/L,1 min,50°C,and 5 min,respectively.A test paper with good color rendering effect,reproducibility,accuracy,and surface morphology was achieved.Furthermore,the color range of test paper for quick measurement of reducing sugar was 0.01³.00 mol/L.More importantly,the fast and semi quantitative detection of reducing sugar is realized.Finally,the performance and the effect of storage time on the color rendering performance of rapid testing paper for reducing sugar was studied.The results showed that the treatment improved the physical properties of the paper,such as the tensile strength,the capillary rise,the permeability and the bulk.The strength and whiteness of test paper base decreased little when the aging temperature was 120°C.Compared with the rapid qualitative filter paper as the paper base,the chromogenic effect of the test paper is deepened,and the detection time is shortened to 4 min.With the increase of storage time,the test paper slightly turned yellow,and the detection time increased while the chromogenic degree decreased.