Selenium is one of the important trace elements in the human body.Its deficiency will directly affect human health.With people's attention to health,the content of selenium in food has gradually attracted attentio...Selenium is one of the important trace elements in the human body.Its deficiency will directly affect human health.With people's attention to health,the content of selenium in food has gradually attracted attention.However,detecting selenium compounds in complex samples remains a challenge.In this work,we built an online heating-reaction device.This device combines the electrospray extraction ionization mass spectrometry(EESI-MS)with the heating reaction device,which can simultaneously detect various selenium compounds in complex liquid samples.Under acidic conditions,the sample was heated and catalyzed by a heating reaction device,so that the SeO~(2-)_(3)and O-phenylenediamine(OPD)could generate 1,3-dihydro-2,1,3-benzoselenadiazole.Based on the above reactions,we can detect organic selenium,inorganic selenium and other compounds in liquid samples by organic mass spectrometry.In this experiment,we determined the content of three forms of selenium:selenomethionine(SeMet),l-selenocystine(SeCys(2)),and sodium selenite.The calibration curves for SeMet,SeCys(2),and sodium selenite showed strong linearity within a range of 0.50-50.00μg/L.The limits of detection(LOD)for the three compounds were 0.22,0.27,and 0.41μg/L,respectively.The limits of quantification(LOQ)were 0.68,0.81,and 1.23μg/L,respectively.Spiked recoveries at three levels ranged from 98.8%to 106.1%.In addition,this method can simultaneously detect three selenium compounds and three other specific chemical components in tea infusion samples,providing a rapid and efficient method for identifying tea quality.展开更多
The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions ob...The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions obtained from different cultivars and different parts of new shoots were varied. There were many chemical components participating in the formation of green tea cream. However, there were only the contents of caffeine （Y=0.85, P〈0.01） and polyphenols （Y=0.65, P〈0.05） in the original green tea infusion highly correlated with the amount of green tea cream. Stepwise regression analysis of overall chemical components indicated that the contents of caffeine and gallated catechins in the original green tea infusion had a significant effect （P〈0.01） on green tea cream levels. Cream （g L-1）=-172.071＋ 0.129×Ccaffeine＋0.024×Ggallated catechins （R2=0.936）. The amount of green tea cream can be predicted by the contents of gallated catechins and caffeine in the original tea infusion. Principal component analysis also indicated that catechins, minerals, and polysaccharides were the important chemical components in the formation of green tea cream.展开更多
In this study, infused tea leaves as a low-cost adsorbent have been used in the removal of the Pb<sup>2+</sup>, Fe<sup>2+</sup> and Cd<sup>2+</sup> ions from aqueous solution. The a...In this study, infused tea leaves as a low-cost adsorbent have been used in the removal of the Pb<sup>2+</sup>, Fe<sup>2+</sup> and Cd<sup>2+</sup> ions from aqueous solution. The adsorption study was carried out in a batch process and the effects of parameters such as initial pH, adsorbent dose, contact time and initial metal ion<sup> </sup>concentration were investigated. Experimental results showed that the maximum adsorption of metal ions occurred at pH 5 for Pb<sup>2+</sup> and Fe<sup>2+</sup> and at pH 6 for Cd<sup>2+</sup>. Adsorption of metal ions increased with increasing adsorbent concentration and contact time. The isothermal data for the adsorption of metal ions by infused tea leaves were found to fit well with the Langmuir equations. Based on the experimental data of the Langmuir isotherm model, the maximum adsorption capacities of the metal ions onto the infused tea leaves were found in the order of Pb<sup>2+</sup> > Cd<sup>2+</sup> > Fe<sup>2+</sup> with the adsorption capacities of 26.32 mg·g<sup>ǃ</sup>, 14.29 mg·g<sup>ǃ</sup> and 12.38 mg·g<sup>ǃ</sup> respectively. The adsorption process followed the pseudo-second order reaction and the corresponding rate constant were found to be 4.30 × 10<sup>Dž</sup> g·mg<sup>ǃ</sup>·min<sup>ǃ</sup>, 1.75 × 10<sup>ǃ</sup> g·mg<sup>ǃ</sup>·min<sup>ǃ</sup> and 1.45 × 10<sup>DŽ</sup> g·mg<sup>ǃ</sup>·min<sup>ǃ</sup> for Pb<sup>2+</sup>, Fe<sup>2+</sup> and Cd<sup>2+</sup> ions respectively.展开更多
In this work,we reported a simultaneous determination approach for Pb(II),Cd(II)and Zn(II)atμg L 1concentration levels using differential pulse stripping voltammetry on a bismuth film electrode(BiFE).The BiFE could b...In this work,we reported a simultaneous determination approach for Pb(II),Cd(II)and Zn(II)atμg L 1concentration levels using differential pulse stripping voltammetry on a bismuth film electrode(BiFE).The BiFE could be prepared in situ when the sample solution contained a suitable amount of Bi(NO)3,and its analytical performance was evaluated for the simultaneous determination of Pb(II),Cd(II)and Zn(II)in solutions.The determination limits were found to be 0.19μg L 1for Zn(II),and0.28μg L 1for Pb(II)and Cd(II),with a preconcentration time of 300 s.The BiFE approach was successfully applied to determine Pb(II),Cd(II)and Zn(II)in tea leaf and infusion samples,and the results were in agreement with those obtained using an atomic absorption spectrometry approach.Without Hg usage,the in situ preparation for BiFE supplied a green and acceptability sensitive method for the determination of the heavy metal ions.展开更多
基金financially supported by Jiangxi University of Chinese Medicine School-level Science and Technology Innovation Team Development Program(No.CXTD22005)PhD research startup fund of Jiangxi University of Chinese Medicine(No.2023BSZR005)。
文摘Selenium is one of the important trace elements in the human body.Its deficiency will directly affect human health.With people's attention to health,the content of selenium in food has gradually attracted attention.However,detecting selenium compounds in complex samples remains a challenge.In this work,we built an online heating-reaction device.This device combines the electrospray extraction ionization mass spectrometry(EESI-MS)with the heating reaction device,which can simultaneously detect various selenium compounds in complex liquid samples.Under acidic conditions,the sample was heated and catalyzed by a heating reaction device,so that the SeO~(2-)_(3)and O-phenylenediamine(OPD)could generate 1,3-dihydro-2,1,3-benzoselenadiazole.Based on the above reactions,we can detect organic selenium,inorganic selenium and other compounds in liquid samples by organic mass spectrometry.In this experiment,we determined the content of three forms of selenium:selenomethionine(SeMet),l-selenocystine(SeCys(2)),and sodium selenite.The calibration curves for SeMet,SeCys(2),and sodium selenite showed strong linearity within a range of 0.50-50.00μg/L.The limits of detection(LOD)for the three compounds were 0.22,0.27,and 0.41μg/L,respectively.The limits of quantification(LOQ)were 0.68,0.81,and 1.23μg/L,respectively.Spiked recoveries at three levels ranged from 98.8%to 106.1%.In addition,this method can simultaneously detect three selenium compounds and three other specific chemical components in tea infusion samples,providing a rapid and efficient method for identifying tea quality.
基金supported by the Special Scientific Research Funds for Commonweal Section of the Ministry of Agriculture, China (nyhyzx07-3-35)the Natural Science Foundation of Zhejiang Province, China (R3090394)the Key Laboratory of Processing and Quality Control of Tea & Beverage Plants Products, Ministry of Agriculture, China (2010K1004)
文摘The relationship between the amount of tea cream and the chemical components contents in the original green tea infusion was investigated. The results showed that the amounts of tea cream in the green tea infusions obtained from different cultivars and different parts of new shoots were varied. There were many chemical components participating in the formation of green tea cream. However, there were only the contents of caffeine （Y=0.85, P〈0.01） and polyphenols （Y=0.65, P〈0.05） in the original green tea infusion highly correlated with the amount of green tea cream. Stepwise regression analysis of overall chemical components indicated that the contents of caffeine and gallated catechins in the original green tea infusion had a significant effect （P〈0.01） on green tea cream levels. Cream （g L-1）=-172.071＋ 0.129×Ccaffeine＋0.024×Ggallated catechins （R2=0.936）. The amount of green tea cream can be predicted by the contents of gallated catechins and caffeine in the original tea infusion. Principal component analysis also indicated that catechins, minerals, and polysaccharides were the important chemical components in the formation of green tea cream.
文摘In this study, infused tea leaves as a low-cost adsorbent have been used in the removal of the Pb<sup>2+</sup>, Fe<sup>2+</sup> and Cd<sup>2+</sup> ions from aqueous solution. The adsorption study was carried out in a batch process and the effects of parameters such as initial pH, adsorbent dose, contact time and initial metal ion<sup> </sup>concentration were investigated. Experimental results showed that the maximum adsorption of metal ions occurred at pH 5 for Pb<sup>2+</sup> and Fe<sup>2+</sup> and at pH 6 for Cd<sup>2+</sup>. Adsorption of metal ions increased with increasing adsorbent concentration and contact time. The isothermal data for the adsorption of metal ions by infused tea leaves were found to fit well with the Langmuir equations. Based on the experimental data of the Langmuir isotherm model, the maximum adsorption capacities of the metal ions onto the infused tea leaves were found in the order of Pb<sup>2+</sup> > Cd<sup>2+</sup> > Fe<sup>2+</sup> with the adsorption capacities of 26.32 mg·g<sup>ǃ</sup>, 14.29 mg·g<sup>ǃ</sup> and 12.38 mg·g<sup>ǃ</sup> respectively. The adsorption process followed the pseudo-second order reaction and the corresponding rate constant were found to be 4.30 × 10<sup>Dž</sup> g·mg<sup>ǃ</sup>·min<sup>ǃ</sup>, 1.75 × 10<sup>ǃ</sup> g·mg<sup>ǃ</sup>·min<sup>ǃ</sup> and 1.45 × 10<sup>DŽ</sup> g·mg<sup>ǃ</sup>·min<sup>ǃ</sup> for Pb<sup>2+</sup>, Fe<sup>2+</sup> and Cd<sup>2+</sup> ions respectively.
基金supported by the National Natural Scientific Foundation of China(21175112)the Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry,SOA,(GCMAC 1204)the Fujian Key Projects of Science and Technology(2011YZ0001-1)
文摘In this work,we reported a simultaneous determination approach for Pb(II),Cd(II)and Zn(II)atμg L 1concentration levels using differential pulse stripping voltammetry on a bismuth film electrode(BiFE).The BiFE could be prepared in situ when the sample solution contained a suitable amount of Bi(NO)3,and its analytical performance was evaluated for the simultaneous determination of Pb(II),Cd(II)and Zn(II)in solutions.The determination limits were found to be 0.19μg L 1for Zn(II),and0.28μg L 1for Pb(II)and Cd(II),with a preconcentration time of 300 s.The BiFE approach was successfully applied to determine Pb(II),Cd(II)and Zn(II)in tea leaf and infusion samples,and the results were in agreement with those obtained using an atomic absorption spectrometry approach.Without Hg usage,the in situ preparation for BiFE supplied a green and acceptability sensitive method for the determination of the heavy metal ions.
