Detections Of Common Carbohydrates Based On Fluorescence Spectroscopy

Carbohydrate is a kind of important carbon hydrate widely distributed in nature.It is not only an important structural substance of organisms,but also the main source of life activities required by organisms.Carbohydrate is often used as the main raw materials and auxiliary materials in the industry of food,and is also one of the main ingredients in most foods.A large number of medical studies have shown that excessive intake of sugar weakens the immune system,leading to obesity,arteriosclerosis,hypertension,diabetes and endanger the life safety of patients with diabetes and other special groups.Therefore,quantitative detection of carbohydrate in food is of great significance to protect the health of ordinary people and the life safety of special people.Common carbohydrates have weak fluorescence or no fluorescence,so it is difficult to detect them directly by fluorescence spectroscopy.But dairy products,honey and other foods have stronger fluorescence than common carbohydrates,and their system are more complex,which will have a great impact on the detection results of common carbohydrates.Thus,it is very difficult to detect weakly fluorescent substances in complex environment.Carbon dots,as new fluorescent nanomaterials,have good fluorescence characteristics and are often used as fluorescent probes to detect specific substances in complex environments.Through the fluorescence response between the fluorescent probe and the object to be measured,the detections of the object to be measured in complex system can be realized.This article shows how to detect common carbohydrates(glucose,fructose and lactose)in dairy products and honey by using fluorescence spectrum technology,and using carbon dots as the fluorescent probes.The main work is as follows:1.Detection of glucose in milk based on phenolic hydroxyl carbon dots(CDs)as the fluorescence probe.In this work,it was found that hydrogen peroxide could significantly quench the fluorescence intensity of CDs.Therefore,the CDs rich in phenolic hydroxyl group was used as a fluorescence probe to detect the concentration of glucose combined with enzymatic method.A highly sensitive and selective method for glucose detection was developed.The results showed that the quenching degree of CDs fluorescence probe had a good linear relationship with glucose concentration when the concentration of glucose was 10-100μM.The determination coefficient(R~2)was 0.968,and the detection limit(LOD)was 0.68μM by calculation.The recovery rate of glucose concentration in milk samples was 97.30%-101.05%,and the relative standard deviations(RSD)were not more than 1.62%.2.Detection of fructose in honey based on 3-aminobenzenoborate CDs as fluorescent probe.In this work,by using 3-aminobenzenoborate as precursor,the blue CDs was synthesized by hydrothermal method.The fluorescence was enhanced by hydrogen bonding between the CDs and the fructose.That makes the detection of fructose in honey come true.A rapid and sensitive method for the determination of fructose was established.The results showed that when the concentration of fructose was 1μM-1 m M in aqueous solution,there was a linear range between the intensity of CDs fluorescence and the concentration of fructose.The determination coefficient R~2 was 0.987,and the LOD was 0.078μM.When the fructose in honey was quantitatively detected,the relative standard deviation was not more than 3.76%.3.The CDs modified by N,S,B was used to detect lactose in Shuhua milk as a fluorescent probe.This work was improved and expanded on the basis of the first work,and the CDs were more sensitive to hydrogen peroxide.Combined with enzyme method,a sensitive,accurate and rapid method for lactose detection was established.When the concentration of lactose was 0.5μM-1 m M,there was a linear range between the quenching degree of CDs fluorescence and the concentration of lactose.The determination coefficient R~2 was 0.980,and the LOD was 4.8μM.The recovery rate was 96.49%-108.04%with relative standard deviations less than 3.23%.In this article,fluorescence spectroscopy was used to detect glucose,fructose and lactose,which expanded the application of fluorescence spectroscopy in the detection of carbohydrates.