Preliminary Studies Of Changes And Identification Of Toxins During Grian Milewing

This topic firstly studies the correlation and changes of total counts of molds and yeastsand wheats qualities under different levels of pollution. Mathematical models was establishedand verified passing through experimental data. Secondly, aflatoxin B1of grains wasdetermined by high performance liquid chromatography (HPLC) combined with electrosprayionization mass spectrometry(ESI-MS). Pretreatment method, chromatographic conditionsand mass spectrometer conditions were respectively optimized. Finally, the components ofmycotoxins were primarily identified by high performance liquid chromatography (HPLC)tandem mass spectrometry (MS/MS). The results were got as follows.When wheats were gradually contaminated, bulk weigh, grain weight, hardness,germination rate, wet gluten content, dry gluten content, gluten index, absorption,development time, valorimeter value, tensile curve area, tensile resistance, extensile rate andmaximum tensile resistance separately showed downtrend. At the same time, total counts ofmolds and yeasts, degree of softening, extensile rate and maximum extensile rate respectivelyshowed rising trend.Regression equations of mathematical molde in experiment was got as follow.Y=-8323.899X2+123.628X1-11633.727X17+16799.679X10+2973.845X7+415.119X3-1778.245X5+17598.095(X2: grain weight, X1: bulk weigh, X17: extensile rate, X10:development time, X7: gluten Index, X3: germination rate). The result indicates thatestablished mathematical evaluation model has certain statistical significance and thepractical significance.Aflatoxin B1of grains was determined by high performance liquid chromatography(HPLC) combined with electrospray ionization mass spectrometry. Methods: The sampleswere extracted by CH3OH and cleaned with PEP. The separation was performed on aXDB-C18column (4.6mm×150mm×5μm), acetonitrile and water as mobile phase (gradientelution). The selected ion monitoring mode was selected to quantify. Results: The linearregression equation was got as follow. Y=23.036X+5.2596. The correlation coefficient was0.9998. The recoveries ranged from69.989%to77.494%. The relative standard deviationof this method was between2.145%and6.219%. The lowest limit of detection was found tobe around1.105μg/kg. Aflatoxin B1was measured with this method in moldy wheat, theflour of system and wheat bran. The components of mycotoxins in grains was determined by a liquidchromatography-tandem mass spectromery (LC-MS/MS) method by UV maximumabsorption wavelength, total ion current, selected ion map and detailed fragment of tandemmass spectrometry with standard. The molecular of every components and detailed fragmentof tandem mass spectrometry were provided with this method. It is consistent between theresults of this method and identified compounds. This shows the feasibility of this method insome cases. Certainly, it is also very important for exploring unknown mycotoxins.