Study On The Detection Method Of 5'-GMP In Braised Brine Based On Electrochemistry

Braised brine played a key role in the processing of marinated meat products,its ingredients,especially the umami substances,were important for the flavor of the marinated meat products.5'-guanylate?5'-GMP?was a representative substance of umami.The detection methods for 5'-GMP content were concentrated on the use of large-scale detection instruments,which were complicated and time-consuming.Today,electrochemical detection had become a hot spot in the field of detection.The electrochemical workstation was easy to operate and had high sensitivity,it was frequently used for quantitative detection of harmful or functional substances in food.In this paper,5'-GMP electrochemical sensor was researched and prepared,and the applicable conditions,detection methods and detection range of it were explored.The sensor was applied to the detection of 5'-GMP in Dezhou braised brine,and the detection results were compared with high performance liquid chromatography?HPLC?to verify its accuracy.The main research contents and results are as follows:?1?The prepared sulfonated-multiwalled carbon nanotubes?SMWCNTs?was mixed with[Ru?bpy?₂?dpp?]Cl₂ to drop coated onto glassy carbon electrode which modified with gold nanoparticles.Bare glassy carbon electrode,SMWCNTs,SMWCNTs/Au,[Ru?bpy?₂dpp]²⁺/SMWCNTs/Au modified glassy carbon electrodes were immersed in0.1mmol/L 5'-GMP solution,respectively.The electrochemical response of each electrode was characterized by cyclic voltammetry?CV?.The results showed that the SMWCNTs/Au and[Ru?bpy?₂dpp]²⁺/SMWCNTs/Au modified electrodes could generate oxidation peaks for 5'-GMP.?2?The conditions such as the scanning speed,the enrichment time,and the pH of the electrolyte were experimentally studied.When the sweep speed of CV was in the range of100 to 180 mV/s,the enrichment time was in the range of 200 to 300s,and the pH of electrolyte was 3,the sensor's response current had the best peak shape and a larger peak value.CV was used to characterize the response of 5'-GMP electrochemical sensor in different concentrations of 5'-GMP standard solution.Under the optimum conditions,the5'-GMP electrochemical sensor showed a linear current response to the substrate concentration in the range from 0.01 to 0.5mmol/L with a detection limit of 0.0014mmol/L in 5'-GMP detection.Linear equation:y??A?=0.6707x??mol/L?+136.95,R²=0.9914.Additionally,5'-GMP electrochemical sensor detection exhibited high selectivity,good repeatability and stability.?3?The 5'-GMP electrochemical sensor was used for the detection of actual samples,and the accuracy of it was verified by camparing with HPLC method.The results detected by 5'-GMP electrochemical sensor was similar with HPLC method.In summary,the5'-GMP electrochemical sensor had high accuracy with fast detection speed and simple operation.