Objective Tea was digested by 2MDS-2000 microwave clearup system.Method Pb,As,Cd and Ni were determined.This paper study the method of dealing with the tea sample and determination conditions by ICP-AES.Result The rate of recovery of the elements is from 84.5%~115%,and the relation standard devition(RSD) is less than 9.0%.Conclusion The results was satisfactory for tea.
Objective With the rapid development of wine,more and more people begin to pay more attention to its ingredients.Method Fo ur kindsof wine were studied by ICP-MS to detect the heavy metals and microelements.health.In addition to microelements,contents of heavy metals(As,Cr,Pb and Cd)are also an impo rtant standard to identify the quality of wine,and the resuhs showed that wine contains little heavy metals,whose sequence is(1ess than 0.5 μg·mL-1) As,Cr,Pb,Cd,As the datashowed that the wine meets the national hygiene standards.
A method was developed for the determination of 12 carbamate pesticide residues in sugarcane by high performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).The residues in the samples were extracted by acetonitrile,cleaned up by developed QuEChERS method,and then analyzed by using HPLC-MS/MS in multiple reaction monitoring(MRM) mode via positive electrospray ionization.External standard method was used to determine the residue contents with a good linear relationship(r20.995).The limits of quantification(LOQ) were 0.03~0.19 μg/kg.The recoveries of carbamate pesticide residues at three levels of 10,50,and 100 μg/kg were from 81.3% to 108.1% with the relative standard deviations(RSDs) of 0.8%~4.7%(n=6) in sugarcane.The method is simple,rapid and characterized with acceptable sensitivity and accuracy to meet the requirements of the pesticide residue analysis.This developed procedure is suitable for the determination of carbamate pesticide residues in sugarcane.
A new method was established to determine sulfur dioxide in white granulated sugar by chromatography of ions. IonPac AS11 as splitter, NaOH as eluent, gradient elution, suppressed conductivity detection, qualitative analysis with retaining time, quantitative analysis with external reference method. This method had good linearity (r=0.9994) for the concentration of sulfur dioxide in white granulated sugar ranged from 0.10～50 mg/kg. RSD of samples ranged from 0.9%～2.1%, the average recoveries of samples were between 97.0%～102.0%. The method detection limit was 0.30 mg/kg. There was no significant difference between the result by this method and those by the national standard method, the results were satisfying.
A method of simultaneous determination of 5 preservatives and sweeteners in mooncakes by microwave extraction-high performance liquid chromatography was set up.In this paper,mobile phase and detection wavelength were researched.Orthogonal experiment was carried out to optimize the conditions for microwave extraction.Then extraction effect by microwave extraction was compared to the one by ultrasonic extraction.The result showed that microwave extraction was more efficient and it costed only 1/15 of the time ultrasonic extraction need.The analytical method showed that the limits of detection were 0.2mg/kg~0.70mg/kg,the linear ranges were 0.4mg/L~400mg/L and the recoveries in spiked samples were 96.0%~103.2%,which satisfied the need of analytical detection.
The method to determine the reducing sugar(glucose,fructose)in sugarcane was established.Eluent gradient elution with NaOH,glucose,fructose in the CarboPacTMPA1O high performance anion-exchange column(HPAEC)can be completed within 35 min in the separation.The use of pulsed amperometric detector (PAD)were measured,glucose,fructose detection limit(injection 25μL,S/N=3)were 1μg/L,2μg/L,and both have a wide linear range(0.1~100 mg/L).The relative standard deviation of the sample measured at 0.3%～3.8%, and recoveries at between 95.8%～101.0%;and measured with the titration of the reducing sugar content of a comparative analysis of the results within a deviation of 13.7%.The determination method shows a good separation effect and high sensitivity,requires a simple sample pre-treatment,and is suitable for the analysis of reducing sugar in sugar.
A method was developed for the determination of 16 phthalate acid esters in sugar by gas chromatograph mass spectrometry(GC-MS).The residues in sugar were extracted by hexane,and then analyzed by using GC-MS in selecting ion mode(SIM).External standard method was used to determine the residue contents with a good linear relationship(r20.995).The limits of quantification(LOQ) was 0.20～5.2 μg/kg.The recoveries of phthalate acid esters at three levels of 20,40,and 100 μg/kg were from 81.2% to 106.3% with the relative standard deviations(RSDs) of 0.67%～8.8%(n=6) in sugar.The method is simple,rapid and characterized with acceptable sensitivity and accuracy to meet the requirements of the determination of phthalate acid esters in sugar.
By the determination of Color in white granulated sugar according to the method in National Standard White Granulated Sugar GB317-2006,the influence factors of uncertainty were found,and the mathematical model was established to calculate the component uncertainty.The combined standard uncertainty and the expanded uncertainty of the method were given eventually.
By the determination of Copper in white granulated sugar according to the method in National Standard Determination of copper in food GB/T 5009.13-2003,the influence factors of uncertainty were found,and the mathematical model was established to calculate the component uncertainty.The combined standard uncertainty and the expanded uncertainty of the method were given eventually.
