Study On Visual Rapid Detection Method Of Cadmium And Iron Ion In Food

The pollution of heavy metal is increasing and its accumulation in the human body can lead to a series of hazards.Therefore,the detection of heavy metal ions in food is particularly important.The traditional methods of detecting heavy metals generally utilize large instruments,and they are not applicable for the on-site inspection of food samples.At present,the process of test paper making and detection of cadmium ion is more complex,so it is of great significance to research and invent a simple and convenient test paper.In addition,the fluorescence method studied in this paper greatly simplifies the synthesis steps and meets the requirements of rapid detection.We have synthesized the supporting material mesoporous silica,which was used to react with cadmium chromogenic agent to form composite materials under dark conditions.The composite materials were characterized by transmission electron microscopy,nitrogen adsorption desorption isotherm and fourier transform infrared spectroscopy,and the result showed that cadmium chromogenic agent were loaded in mesoporous silica.After a series of conditional optimization,the method of rapid detecting cadmium was established:The pH in the ammonia environment was about 11.30,and the test paper was immersed in the solution for 15 minutes,then the color of the test paper was compared with the standard color scale to obtain the approximate concentration of cadmium ions.The method of detecting cadmium ions was established for the detection of maize,wheat,rice and other samples.The detecting results were not detected and the result of ICP-MS was 0.0001,0.00007 and 0.00009 ?g/mL.The detection limit of cadmium ion could reach 0.1 ?g/mL,and the qualitative and semi-quantitative detection of cadmium ion was realized.A new chromogenic material which was specifically identified for iron ions was synthesized from gallic acid and copper nitrate.The material and iron ions can react with iron ions to form a complex with fluorescence.In the presence of 0.001 mol/L sodium hydroxide,the fluorescence of the complex increased with the addition of a certain amount of iron ions,and the concentration of iron ranged from 0.050 ?g/mL to 0.500 ?g/mL.The fluorescence enhancement degree of the complex has a good linear relationship with the iron ion concentration,R2 = 0.9945 and the detection limit was 0.0381 ?g/mL.The recovery rate of iron ion were 99.3%-116.7%,and the RSD value was less than 8%.The method of detecting iron ions was used to detect the actual samples such as laboratory water and boiler water.The result of this method was 0.1138,0.1169 p.g/mL,and the result of ICP-MS was 0.1015,0.0988 ?g/mL.It can be proved that the two methods established in this paper are of good accuracy and can meet the requirements of rapid detection in actual tests.