Application Of In Situ Electrospray Ionization Mass Spectrometry In Agricultural Detection

In situ mass spectrometry is an emerging mass spectrometric method with various advantages over traditional analytical methods,such as high detection efficiency,easy operation,and no sample pretreatment.To investigate its detection capability in the agricultural field,two new in situ electrospray ionization mass spectrometry methods,on-line extraction electrospray ionization mass spectrometry and novel thermal desorption ionization mass spectrometry,were developed and performed in a variety of complex sample matrices.The on-line extraction electrospray ionization method uses sunflower seed husk as both sample extraction device and spray device,and applies high voltage to the husk to organically combine sample extraction and electrospray mass spectrometry analysis,and the extracted components are directly detected by spray.Using this method,melamine in milk powder,atrazine in soil,α-cadherine in potato,and glycerol esters in soybean oil were analyzed without sample pretreatment.In the detection of melamine and atrazine,the peaks were good,with the lowest detection concentration of 0.01 mg/kg,and the husk were equivalent to an "electric pool" in the detection of complex matrix with strong adsorption,which effectively improved the detection sensitivity.In the detection of triglycerides in soybean oil,the unique triglycerides of soybean oil were detected,which is of great significance for the rapid identification of edible oils.The novel thermal desorption ionization mass spectrometry combines an atomization chamber with a solvent electrospray ionization device.The atomization chamber desorbs the sample at high temperature,and the solvent electrospray device in an orthogonal position ionizes the solvent to form a solvent aerosol,which is fused with the sample aerosol and then enters the mass spectrometer to be detected.Stevioside in stevia,glycerides in soybean oil,glucose,sucrose,and caffeine in cola were detected using this device.More compounds were detected in stevia with cola than in conventional electrospray ionization mass spectrometry;ammonia compounds of characteristic triglycerides of soybean oil were detected in the detection of triglycerides;and good peaks were detected in the detection of sugars,which expanded the detection range compared with conventional thermal desorption mass spectrometry.The on-line extraction ionization mass spectrometry and new thermal desorption ionization mass spectrometry developed in this experiment not only shorten the detection time of the sample,but also expand the detection range of the sample,and have good detection sensitivity,which provides the application of possible in situ mass spectrometry in the field of agricultural detection.