This article has been cited by other articles in PMC. Abstract Tea is one of the most common drinks in all over the world. Rapid urbanization and industrialization in recent decades has increased heavy metals in tea and other foods.
Results and Discussion 3.
According to t-test, no statistically significant differences between corrected and uncorrected concentrations were found. Similar result was found by Cai and coworkers [ 15 ] for citrus leaves standard reference materials digested with HNO3 and H2O2, reagents also used in the present study.
Table 2 shows the analytes recovery in the spiked samples submitted to the different preparation procedures for determining total arsenic, cadmium, and lead in rice. Recovery of total arsenic, cadmium, and lead from rice sample submitted to different preparation procedures ashing in muffle oven, acid digestion under heating on metallic block or hot plate, and acid digestion assisted by microwave radiation.
Recoveries varied from This finding highlights the possibility of using all of the sample preparation procedures employed in the present study, including arsenic determination whose volatility is well known.
|ISO - Zinc -- Determination of lead and cadmium contents -- Polarographic method||The lowest level of Pb was found in products of Saudi Arabia 0. The mean differences of local and exported products were significant at the 0.|
|Determination of lead, cadmium and arsenic in infusion tea cultivated in north of Iran||Get Full Essay Get access to this section to get all help you need with your essay and educational issues.|
Soylak and coworkers [ 18 ] also compared various sample preparation procedures for determination of trace elements in Turkey spices. Recoveries ranged from The results found in the present study are in agreement with the data reported by Wei et al.
Nowadays, researches on sample preparation procedures have advanced, leaning more and more to the microwave technology, becoming difficult to find present-day publications using other procedures.
The advantages of microwave technology are undeniable, but the use of less resourceful instruments may eventually be appropriate, providing good results for the analytes under study.
Method Validation Studies The overall performance of the proposed method for total arsenic, cadmium, and lead determination in rice is summarized in Tables 3 and 4.
LOD, LOQ, working range, and correlation coefficient of calibration curve for the microwave digestion method. LODs and LOQs results were considered acceptable as the values were below the limits established by the Brazilian legislation for arsenic, lead, and cadmium for rice and its derivatives: The linearity of the calibration curve was evaluated by investigating the correlation coefficient of the calibration curves.
The values were higher than 0. Relative bias Table 4 was assessed through the difference between the mean value of obtained results and the certified values. For all elements, the RSD repeatability was in compliance with the European Commission Decision [ 48 ], and it did not exceed Therefore, as expected, the use of microwave oven for rice acid digestion was appropriate for determining the total arsenic, cadmium, and lead concentrations in rice using ICP-MS.
Method Application The above was method applied for quantifying the concentration of total arsenic, cadmium, and lead in 37 rice samples polished, parboiled, and brown rice. Results are summarized in Table 5.
Concentrations of total arsenic, cadmium, and lead in the analyzed rice samples average values. According to Table 5of 37 analyzed samples, 35 showed total arsenic concentration higher than the LOQ, ranging from 0. In two polished rice samples, total arsenic concentration was lower than LOQ.
The average total arsenic concentration in parboiled rice was lower than that found in other rice types 0. This value was higher than that established by the Brazilian legislation [ 20 ] and the Codex Alimentarius [ 49 ], which is 0.
This sample was considered unsatisfactory for human consumption. Excepting the brown rice sample, total arsenic concentrations were in agreement with the maximum level established for total arsenic in raw rice. Total arsenic mean concentrations found in the present study were in agreement with those cited in the literature; and the respective authors pointed out the evident occurrence of the highest arsenic concentrations in brown rice.
This occurs owing to the fact that rice plants concentrate this element in the outer layer of the grain, in the region corresponding to the pericarp. A great amount of arsenic is removed during the rice polishing [ 2150 — 52 ].The results of Cadmium and Lead contents in samples of raw, washing, boiling – drained and cooking rice from 10 main agricultural areas in Gillan province; the north of Iran are shown in table 1 and 2 respectively.
Results show that the mean content of Cadmium and Lead in all samples from Gillan province is over. For the determination of lead and cadmium, 5 ± g of each samples was weighed into a ml beaker and 50 ml of freshly (v/v) H2O2 (30%):HNO3 (65%) was added slowly in portion.
Each beaker was covered with a watch glass and stored at room temperature for 48 h. Tissues were homogenised and, g of dry weight sample was digested with 5 ml of HNO 3, for lead and cadmium determination, in Teflon vessels in microwave oven (ANTON PAAR closed vessel microwave digestion system, Graz, Austria).
The metal contents in the samples, expressed in µg kg-1 wet weight, varied from to with an average value of for lead and from to with an average value of for cadmium. prepared for lead and cadmium determination (Figure S1). Kohl was sold in powder form in black, grey, brown, reddish brown and silver color, and it was also available in natural unprocessed form as .
Zinc -- Determination of lead and cadmium contents -- Polarographic method The method is applicable to Zn 99,, Zn 99,99 and Zn 99, Although these types of zinc do not normally contain any thallium or indium, these two elements, if present, can interfere in this determination.