Determination of hexavalent chromium in cigarette tipping paper by atomic absorption spectrometry
The National Tobacco Quality Inspection Center issued the YQ/T60-2015 "Determination of hexavalent chromium for cigarette tipping paper - continuous flow method" test standard. However, many units have not purchased a flow analyzer for the time being, and the total chromium content is still determined by atomic absorption. The continuous flow method cannot be used to detect the content of Cr6+. Therefore, it is decided to effectively separate Cr3+ and Cr6+ by the method of pre-treatment and detection conditions for cigarette tipping paper, and achieve the goal of determining the content of Cr6+ in cigarette tipping paper by graphite furnace atomic absorption spectrometry, for tobacco materials and cigarettes. The safety of the product is correctly evaluated. 1 sample pretreatment method Sample pretreatment of the tipping paper for cigarettes was carried out by selecting wet digestion plus TTA coupling. According to the influencing factors such as the pH value of the test sample, the amount of buffer solution, the concentration of TTA, the temperature and time of the ultrasonic bath, and the standing time, the optimal value of each parameter was determined by single factor analysis. 1) pH value. When the pH is 5.6, Cr (TTA) has the highest volatilization rate. Therefore, the pH was chosen to be 5.6. 2) The amount of buffer solution. When the volume is 3.0 ml, the absorbance of the Cr3+ solution is the most. Therefore, the amount of the buffer solution was selected to be 3.0 ml. 3) TTA concentration. When the concentration is 0.15mo1/L, Cr(TTA) has the highest volatilization rate. Therefore, the concentration of TTA was chosen to be 0.15 mol1/L. 4) Ultrasonic water bath temperature and time. When the temperature is 50 ° C and the time is 15 min, Cr (TTA) has the highest volatilization rate. Therefore, the ultrasonic bath temperature and time were selected to be 50 ° C and 15 min, respectively. 5) Rest time. When left for 60 min, the absorbance of Cr3+ is the most. Therefore, the rest time is chosen to be 60 min. 2 sample selection method selection The influencing factors such as matrix modifier, graphite furnace pretreatment temperature and ashing temperature, pretreatment time and atomization temperature were summarized and summarized, and the optimal value of each parameter was determined by single factor analysis. 1) Matrix modifier. When the concentration is 5 mg/L, Cr(TTA) is completely volatilized. Therefore, a 5 mg/L palladium nitrate solution was selected as the matrix modifier. 2) Pretreatment temperature and ashing temperature. When the temperature is 650 ° C and 1500 ° C, respectively, the absorbance is the most. Therefore, the pretreatment temperature and the ashing temperature were selected to be 650 ° C and 1500 ° C, respectively. 3) Pretreatment time. When Cr 3+ is at 60 s, the volatilization is complete and stable. Therefore, the pretreatment time is chosen to be 60s. 4) Atomization temperature. When Cr 3+ is at 2300 ° C, the absorbance is the most. Therefore, the atomization temperature was chosen to be 2300 °C. 3 Comparison of results between continuous flow method and atomic absorption method At the same time, 12 samples of cigarette tipping paper samples were subjected to Cr6+ measurement by continuous flow method and atomic absorption method. The results were averaged and the RSD of the data was calculated (see Table 4). The two methods for determining the hexavalent chromium content in the tipping paper for cigarettes have an RSDmax of 8.83% <10%, which has good stability and effectiveness. When the content of hexavalent chromium in the tipping paper for cigarettes is high, the RSD of the two detection methods is small, and both methods are applicable; when the content of hexavalent chromium in the tipping paper for cigarettes is low, two The RSD of the detection method is preferably a continuous flow method for the detection of hexavalent chromium. Therefore, in the case where a continuous flow analyzer is not purchased, the atomic absorption method can be used to meet the daily measurement requirements of the hexavalent chromium content in the existing cigarette tipping paper. Responsible editor: Ge This article is posted on the website for the purpose of transmitting more information and does not imply endorsement of its views or confirmation of its description. Article source address: http:// The product is made of food-grade PP material, which is anti-bacterial, insect-proof and not easy to damp. It can be licked and has no peculiar smell. A bowl is double-purpose, can hold water or grain, save time and effort, convenient and practical. The inside of the bowl is professionally polished, the arc does not leave a dead corner, and it is clean after a punch. Capsule Wiggle Dog Bowl,Slow Feeder Puppy Bowl,Anti Spill Dog Bowl,Dog Bowls For Small Dog DongGuan Lucky Pet Products Co., Ltd. , https://www.dgpetproduct.com