To ensure reliable taring, be patient and wait until 0. Handle each sample appropriately. Some samples will require extra care — warm or hot samples should be allowed to cool first, and hygroscopic samples weighed quickly with the balance doors closed to avoid moisture absorption, which will affect your measurements.
For the most accurate measurements of all samples, they should be placed in the centre of the balance. You should also make sure you are using the correct balance for the amount you wish to weigh, and an appropriate sized weighing vessel.
A weighing vessel that is too small will make spilling your sample more likely, dirtying your balance and making your measurement inaccurate, and a vessel that is too large may lead to a proportion of your sample stuck to the vessel.
Sartorius supplies inert parchment weighing boats and papers of all sizes , so there will be one to suit your needs. Avoid contact or disturbance. Your fingerprints can affect the weight of the weighing container once tared, adding mass, so use tongs or gloves to avoid this. Wait for 5 to 10 seconds before you see the reading. If the reading is unstable, the reason may be static electricity. Tips for Improving Accuracy while using Analytical Balance Accuracy is an important aspect of analytical balance, especially in industries such as compounding pharmaceuticals and researching.
Here are some tips to help you attain analytical balance weighing accuracy: Consider the Location — You need to place the balance on a solid level surface to ensure minimum or no exposure to external factors that may affect the reading. The location should have minimal exposure to vibration, humidity, and temperature as these conditions often lead to inaccurate readings by either affecting the sample or balance. Moreover, you can also shield the balance from external factors such as temperature and humidity to maintain the accuracy of readings.
Take into Account the Electrostatic Charge — This is particularly recommended when you are weighing dry and non-conductive samples that are likely to cause weighing errors. The electromagnetic field between the balance and the items can lead to distortion of the weight results.
So, make sure you check for any electrostatic charge before the reading. Calibrate the Scale to Suit the Location — This is important because the effect of gravity on the sample varies with geographic locations. So, ensure that you calibrate or test your scale against an accurate device on a regular basis.
It can be done on-site with the help of calibration weight or in an accredited calibration lab. Also, tare the balance before calibration since it should be level. All these measures are important to maintain the reliability of readings. Have Good Housekeeping Practices — Be sure to prevent the introduction of liquids in the weighing mechanism as this can tamper with the balance. Clean the balance area using cloths that are barely damp or dry.
USP uses a safety factor of two , giving the following equation:. You want to weigh a mg sample and need to decide if a balance will give you an accurate enough reading.
The repeatability of your balance is 0. Plugging those into the equation:. However, if you want to weigh a 10mg sample with the same maximum uncertainty tolerance, a balance with 0. Note that you also need to consider the maximum load tolerance of a balance when deciding which to use. Other indicators of the accuracy of a balance are linearity and eccentricity and you may have permissible values for each of these. Linearity tests use two weights to test the ability of the balance to measure the weight of a load before and after a second load has been placed on the pan.
Adam Equipment precision balances have a readability of 0. What are some common applications of precision balances? Typical functions of precision balances Precision balances tend to have more features than bench scales or compact balances. How to choose the best precision balance for your needs As always, consider your application when you start your search.
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