With the emerging concern on trace element content in rice on both toxicological and nutritional standpoints, validation of analytical method to determine both essential and toxic elements in rice is important in orde...With the emerging concern on trace element content in rice on both toxicological and nutritional standpoints, validation of analytical method to determine both essential and toxic elements in rice is important in order to produce reliable results. Therefore, this study was aimed to validate analytical method to determine As, Cd, Pb, Hg, Cr, Ni, Se, Cu, Mn, Mo, Fe, Co and Zn in rice while giving an overview of the challenges encountered and application of the method to analysis trace elements in selected traditional rice varieties available in Sri Lankan market. Sample digestion was carried out by microwave digestion and analysed by ICP-MS. The analytical method was validated by measuring precision, accuracy, limits of detection (LODs), limits of quantification (LOQs), working and linear range, recovery percentage and measurement uncertainty. They showed that the method is fit for its purpose as those complies with the standard method performance requirements of AOAC. Percentage of relative standard deviations (RSD) of repeatability was not greater than 9.9% and RSDs (%) of reproducibility were not greater than 10.1% for all elements. Mean recoveries varied from 81% to 110%. Limits of detections of elements were in the range of 0.04 - 0.8 mg/kg and LOQs were in the range of 0.05 - 1.2 mg/kg. Expanded uncertainties of trace elements lay between 1.1% and 6.0%. Good agreement with the certified values of Standard Reference Material (SRM) 1568b—Rice Flour analysed by the proposed method with recovery percentages between 89.4% and 105.7% further confirms the accuracy and traceability of the method. The distribution pattern of essential elements in all rice varieties analysed was Mn > Zn > Fe > Cu > Mo > Se > Co. Even though arsenic was detected in all varieties, only the mean concentration of lead of Kaluneenati exceeds the maximum level (FAO/WHO CODEX Alimentarius).展开更多
This work proposes the use of experimental design for optimization of microwave-assisted digestion of bio- morphic ZrO2-ceramic. Cedar wood is used as template and it was infiltrated with ZrO2 via sol-gel process. XPS...This work proposes the use of experimental design for optimization of microwave-assisted digestion of bio- morphic ZrO2-ceramic. Cedar wood is used as template and it was infiltrated with ZrO2 via sol-gel process. XPS, SEM and XRD have been used to verify the effectiveness of the synthesis. The effects of different combination of acids in the digestion of this sample have been optimized taking as response the concentra- tion of several metallic ions measured by ICP-MS.展开更多
The research aims to set up the determination method of heavy metals in tobacco by ICP-MS and analyze its uncertainty. Microwave digest technique is used for decomposition of the tobacco samples. Bi,Sc,Ge and In are e...The research aims to set up the determination method of heavy metals in tobacco by ICP-MS and analyze its uncertainty. Microwave digest technique is used for decomposition of the tobacco samples. Bi,Sc,Ge and In are employed as internal standards to eliminate the interference of the matrix. A method is developed for simultaneous determination of Cr,Cu,As,Cd,Hg and Pb in tobacco from Yunnan Province by ICP-MS,and the measurement uncertainty is evaluated by metrological method. The test results indicate that in the content range of0- 1. 0 g / ml,the linearly dependent coefficient of six elements is 1. 0000,and the RSD achieves 1. 5%- 11%( n = 8). The elemental content in tobacco is as follows: Cr( 2. 92,0. 24) mg / kg,Cu( 3. 64,0. 24) mg / kg,As( 0. 467,0. 025) mg / kg,Cd( 3. 12,0. 15) mg / kg,Hg( 0. 035,0. 006) mg/kg,Pb( 4. 62,0. 36) mg/kg. The uncertainty of sample size,the constant volume of the sample solution can be neglected. It is concluded that the method is accurate,simple,sensitive and rapid.展开更多
The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigat...The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season （before and after precipitation） between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc （133.50-419.30 μg/m3） and aluminum （53.58-378.93 μg/m3） had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters （pH and turbidity） and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere.展开更多
文摘With the emerging concern on trace element content in rice on both toxicological and nutritional standpoints, validation of analytical method to determine both essential and toxic elements in rice is important in order to produce reliable results. Therefore, this study was aimed to validate analytical method to determine As, Cd, Pb, Hg, Cr, Ni, Se, Cu, Mn, Mo, Fe, Co and Zn in rice while giving an overview of the challenges encountered and application of the method to analysis trace elements in selected traditional rice varieties available in Sri Lankan market. Sample digestion was carried out by microwave digestion and analysed by ICP-MS. The analytical method was validated by measuring precision, accuracy, limits of detection (LODs), limits of quantification (LOQs), working and linear range, recovery percentage and measurement uncertainty. They showed that the method is fit for its purpose as those complies with the standard method performance requirements of AOAC. Percentage of relative standard deviations (RSD) of repeatability was not greater than 9.9% and RSDs (%) of reproducibility were not greater than 10.1% for all elements. Mean recoveries varied from 81% to 110%. Limits of detections of elements were in the range of 0.04 - 0.8 mg/kg and LOQs were in the range of 0.05 - 1.2 mg/kg. Expanded uncertainties of trace elements lay between 1.1% and 6.0%. Good agreement with the certified values of Standard Reference Material (SRM) 1568b—Rice Flour analysed by the proposed method with recovery percentages between 89.4% and 105.7% further confirms the accuracy and traceability of the method. The distribution pattern of essential elements in all rice varieties analysed was Mn > Zn > Fe > Cu > Mo > Se > Co. Even though arsenic was detected in all varieties, only the mean concentration of lead of Kaluneenati exceeds the maximum level (FAO/WHO CODEX Alimentarius).
文摘This work proposes the use of experimental design for optimization of microwave-assisted digestion of bio- morphic ZrO2-ceramic. Cedar wood is used as template and it was infiltrated with ZrO2 via sol-gel process. XPS, SEM and XRD have been used to verify the effectiveness of the synthesis. The effects of different combination of acids in the digestion of this sample have been optimized taking as response the concentra- tion of several metallic ions measured by ICP-MS.
基金Supported by Fund Project of Yunnan Provincial Department of Education(2013Y475)Science and Technology Project of State General Administration for Quality Supervision(2013QK071)
文摘The research aims to set up the determination method of heavy metals in tobacco by ICP-MS and analyze its uncertainty. Microwave digest technique is used for decomposition of the tobacco samples. Bi,Sc,Ge and In are employed as internal standards to eliminate the interference of the matrix. A method is developed for simultaneous determination of Cr,Cu,As,Cd,Hg and Pb in tobacco from Yunnan Province by ICP-MS,and the measurement uncertainty is evaluated by metrological method. The test results indicate that in the content range of0- 1. 0 g / ml,the linearly dependent coefficient of six elements is 1. 0000,and the RSD achieves 1. 5%- 11%( n = 8). The elemental content in tobacco is as follows: Cr( 2. 92,0. 24) mg / kg,Cu( 3. 64,0. 24) mg / kg,As( 0. 467,0. 025) mg / kg,Cd( 3. 12,0. 15) mg / kg,Hg( 0. 035,0. 006) mg/kg,Pb( 4. 62,0. 36) mg/kg. The uncertainty of sample size,the constant volume of the sample solution can be neglected. It is concluded that the method is accurate,simple,sensitive and rapid.
基金supported by the Universiti Tunku Abdul Rahman under Universiti Research Grant(No.IPSR/RMC/UTARRF/C1-13/G03)
文摘The study of trace metals in the atmosphere and lake water is important due to their critical effects on humans, aquatic animals and the geochemical balance of ecosystems. The objective of this study was to investigate the concentration of trace metals in atmospheric and lake water samples during the rainy season （before and after precipitation） between November and December 2015. Typical methods of sample preparation for trace metal determination such as cloud point extraction, solid phase extraction and dispersive liquid- liquid micro-extraction are time-consuming and difficult to perform; therefore, there is a crucial need for development of more effective sample preparation procedure. A convection microwave assisted digestion procedure for extraction of trace metals was developed for use prior to inductively couple plasma-mass spectrometric determination. The result showed that metals like zinc （133.50-419.30 μg/m3） and aluminum （53.58-378.93 μg/m3） had higher concentrations in atmospheric samples as compared to lake samples before precipitation. On the other hand, the concentrations of zinc, aluminum, chromium and arsenic were significantly higher in lake samples after precipitation and lower in atmospheric samples. The relationship between physicochemical parameters （pH and turbidity） and heavy metal concentrations was investigated as well. Furthermore, enrichment factor analysis indicated that anthropogenic sources such as soil dust, biomass burning and fuel combustion influenced the metal concentrations in the atmosphere.
