Development Of Miniaturized Detection Equipments For Pollutants Containing Sn And S In Mango Production

Objective:Mango,as a famous tropical and subtropical fruit,plays an important role in agriculture and trade because of its unique flavor and high nutrition.Located in the tropical region,Hainan province has obvious advantages in the development of mango industry,which has become the largest production zone in China.Meanwhile,mango industry has also become one of the backbone industries of Hainan province's tropical efficient agriculture.However,in the production of mango,it may be affected by pollutants containing Sn and S,which not only leads to a reduction in production,but also may cause potential harm to consumer health.Therefore,it is of certain significance for the rapid and accurate detection of Sn and S pollutants in mango production.However,the laboratory instruments are usually bulky,expensive and not portable,and the field analysis is still challenging.The purpose of this study is to develop miniaturized and cost-effective analytical instruments,which can be sensitive,accurate and rapid determination of Sn and S pollutants in mango production.Methods:As for the residual organotin compounds?OTs?in mango,the OTs separated by liquid chromatography?LC?were transformed into volatile gas Sn H₄ by online continuous chemical vapor generation?CVG?technology,which was then excited by glow discharge micropl asma?GD?and emitted characteristic atomic spectrum line at 317.66 nm.With regard to total sulfur dioxide?SO₂?in mango and its drinks,mango drink was entered the system through a six-way valve,and the flesh samples were directly put into the sample bottle in whole or cut into pieces without pretreatment.The carrier liquid?diluted H₂SO₄?acidified the sample to release SO₂ gas,which was then excited by DBD microplasma and emitted characteristic molecular line at 301.9 nm.For the sulfide in mango orchard irrigation water,the water samples were injected into the system through the six-way valve and acidified by the carrier liquid?diluted H₂SO₄?to convert the sulfide into H₂S gas,which is then excited by DBD microplasma and emitted characteristic molecular line at 365.28 nm.The gas-liquid separation of SO₂ and H₂S is facilitated by heating and ultrasonic assistance.Characteristic atomic/molecular emission lines are collected,recorded,and processed by a commercial small charge-coupled device?CCD?.Results:Under the optimal experimental parameters,the linear correlation coefficients?R²?of trimethyltin chloride?TMT?and dimethyltin dichloride?DMTC?were better than 0.99 in the range of 0.1-10?g m L^-1,the detection limits?LODs?were 0.59 and 0.93?g L^-1,respectively,and the recoveries of spiked samples were 73.3-92.6%,relative standard deviations?RSDs?were1.1-5.6%.The linear correlation coefficients?R²?of SO₂was better than 0.99 in the range of 10-100?g m L^-1,LOD was 0.01 mg L^-1,and the recoveries of spiked samples were 83.6%-95.1%,RSDs were 1.1-4.2%.The linear correlation coefficients?R²?of sulfide was better than 0.99 in the range of 1-200?g m L^-1,LOD was 0.10 mg L^-1,and the recoveries of spiked samples were 82.4%-95.0%,RSDs were 2.1%-5.3%.Conclusion:A miniaturized glow discharge microplasma atomic emission spectrometer?GD-AES?was successfully developed for the rapid simultaneous determination of OTs in mango;a miniaturized dielectric barrier discharge microplasma molecular emission spectrometer?DBD-MES?was successfully developed for the online in-situ determination of total SO₂ in mango and its drinks;a miniaturized DBD-MES was successfully developed for the rapid determination of sulfide in irrigation water of mang orchard.The proposed microplasma-emission spectrometers are characterized by accuracy,sensitivity,simple structure,miniaturization,cost-effectiveness,low energy consumption,and operation under atmospheric pressure,and is expected to be applied in the field of mango quality control,with scientific research significance.