16th week

Welcome to the end of the 16th week of SIP/MP :)



For my final post, I would like to share my experience for the last week during TSO duty. This week, I'm tasked to calibrate the instruments in the Inorganic Chemistry Lab. The instruments present is analytical balance, pH meter and top-pan balance.



The protocols for each analytical balance differs due to their own brand which is similar to a handphone. For example; different brand of handphones has different type of functions even though the principle is similar. Hence, a protocol is set aside for each type of brand of analytical balance. Internal calibration is usually automated by the machine itself.



To calibrate the analytical balance, we must first prepare the analytical balance for calibration by cleaning it, ensure that the linearity is correct and change its setup to calibration mode. Although the setup to calibration mode differs from other brands of analytical balance, the main calibration process is similar. Weights of 100g, 200g and 500g is placed for calibration. This weights are specially made and to handle them, we must use the gloves that comes with the weights. If we handle the weights with our bare hands, moisture will be present on the weights and it might produce a wrong reading.



Once the weights are placed and the machine is calibrated, it is tested by placing a weight of 200g three times to ensure that the analytical balance is properly calibrated.



The top-pan balance is similar to the analytical balance however, instead of using weights of 100g, 200g and 500g, we use weights of 2kg and 4kg. After the top-pan balance is calibrated, weight of 4kg is placed on the top-pan balance three times to ensure that the top-pan balance is properly calibrated.



The pH meter is calibrated by using commercially-prepared buffer solution with a fix pH reading of 4.00, 7.00 and 10.00. The pH meter is prepared for calibration by deleting any previous standardization and then setting up the mode for new standardization using the buffer solution provided. The electrode, which is the tool that detects the reading of pH must be washed with DI water before being placed into the different buffer solution to prevent any mis-reading. The pH meter is then tested in the 7.00 buffer solution to ensure that it is calibrated properly.



Calibration of instruments is a very direct process and if we follow the protocol religiously, there should not be any mistakes. If under any circumstances the instruments is faulty, just inform the technician and they will repair the instruments.



Andika Putra

TG01