Sample description Urea, also known as carbamide, is an organic compound composed of carbon, nitrogen, oxygen, and hydrogen. One of the simplest organic compounds is the main nitrogen-containing end product of protein metabolism in mammals and certain fish species. It is also the nitrogen fertilizer with the highest nitrogen content. As a neutral fertilizer, urea is suitable for a variety of soils and plants. It is easy to store, easy to use, and has little effect on soil destruction. It is a chemical nitrogen fertilizer that is currently used in large quantities. Industrially, ammonia and carbon dioxide are used to synthesize urea under certain conditions. The user sample is a urea sample with a purity of 99% and is soluble in methanol, but the solubility limit must be changed once every 3-5 times. --- Instrument Configuration --- 1. S-300 Karl Fischer Moisture Analyzer host; 2. Fully enclosed safety titration cell assembly; 3. Double platinum electrode; 4. Titration tank mixing station; 5. 10ml syringe 6. 1ul syringe 7. Volumetric flask 8. Analyze one of the balances --- Reagents --- Titrant: Karl Fischer reagent, Solvent: anhydrous methanol; Auxiliary reagent: none; --- Instrument parameters --- Control accuracy: 0.5ul Stirring speed: 20% Suction reagent: automatic Accessibility: Method save, the result is automatically calculated and stored, Equipment verification, titration delay. End current: 51μ A Titration delay: 90 seconds End point delay: 10 seconds Drift deduction: not turned on Drift value update: automatic Delay setting: delay titration and end point delay function can be set as needed to deal with insoluble samples --- Detection method --- 1. Inject approximately 50 ml of toluene:ethanol mixed solvent into the titration cell using the "Suction Solvent" function of the instrument. 2. Use the “Blank†function of the instrument to titrate to the end point to remove moisture from the titration cell and the instrument is ready. 3. Accurately extract 10 μL of pure water with a dry micro-needle, dry the needle, select the instrument calibration function, and pour the pure water. Enter the weight of the pure water below the liquid level in the titration cell and start to calibrate. 4. Repeat step 3 and repeat the measurement 3~5 times. The instrument will automatically save the calibration result and calculate the average value as the titer of the reagent. 5. Take about 1000mg of sample with a solid sampler disposable syringe and set aside. 6. Select “Measure†and press the OK button. After weighing, pour the sample into the titration cell. In the injection interface, enter the sample injection weight, and then press the OK button, the instrument automatically starts measuring, and the result is automatically displayed after the end. Karl Fischer Moisture Analyzer Sample Measurement Record Sample Name: Urea Ambient humidity: 61% Ambient temperature: 23 °C Drift correction: 0.0704ul/s Titration: 3.362mg/ml Sequential injection volume mg Titration volume mL Water content mg ​​Determination time m: s Determination result % 1 1145.0 1.305 4.235 4:41 0.383% 2 1197.7 1.405 4.723 3:43 0.394% 3 1525.1 1.805 6.067 3:51 0.398% Average %: 0.3917% RSD deviation %: 1.98432% Conclusion: S-300 automatic Karl Fischer moisture analyzer can quickly and easily detect the moisture content in urea, and the quasi-determination and repeatability can be guaranteed, in line with the requirements of national standard GB/T2441.3-2010. Automatic Massage Collapsible Foot Spa Massager Auto Massage Foldable Foot Spa Massager is a device that provides relaxing and rejuvenating foot massage. It has a collapsible design for easy storage and transport. The massager has multiple massage rollers that target specific pressure points on your feet to deliver a deep tissue massage that helps relieve tension and improve circulation. It also has a heating function that can help soothe sore muscles and promote relaxation. The massager is easy to use and can be controlled with the push of a button. It's a great way to pamper yourself after a long day on your feet or to relieve foot pain and discomfort. Automatic Massage Collapsible Foot Spa Massager,Folding Foot Bath Machine,Foot Spa,Massager Folding Foot Spa Huaian Mimir Electric Appliance Co., LTD , https://www.mmfootspabath.com