Evaluation Of A Module 11 Analysis

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To perform module 11 analysis, we followed Lab safety procedure by wearing safety goggles (Z87 brand), plastic apron, and a pair of latex gloves as proper “PPE”. We proceeded to module 11 analysis by drawing a sample solution from Lab sink Tap into a (250 ml) plastic sample container and closing the lid. We went on preparing the Oakton PCS tester 35 series meter for measurement by rinsing it with DI water. The meter was set for pH (USA) unit. Followed by calibrating with a pH buffer standard solution (4.0. 7.0, 10.0) for three point calibration. The meter was rinsed with DI water. As we proceeded, the meter was calibrated with a conductivity buffer standard solution (1412±14 µS) by following the manufacturer 's instruction. Then, the meter …show more content…

We let the sample solution overflow the bottle for a couple of seconds, then dissolved oxygen 1 and 2 powder pillow were added to the sample. Immediately, the stopper was placed back in the bottle. As we made sure no air is inside the BOD bottle, the bottle was inverted for 5 times to mix. An orange/brown floc precipitation was formed, as an indication of dissolved oxygen present. The floc was slowly settled after 5 minutes, followed by inverting again the BOD bottle for 5 times to mix. This time, we waited until the top half of the solution was clear and the floc was settled at the bottom of the bottle and reagent reaction was completed.

Dissolved oxygen 3 powder pillow was added to the BOD bottle. Immediately, the stopper was placed back in the BOD bottle, the bottle was inverted for 5 times to mix. As the floc was dissolved a yellow color solution was developed, as an indication of oxygen present. We poured the sample solution from the (60 ml) BOD bottle into a plastic graduate cylinder and adjusted the volume to exact 20 ml. Later on, transferred the solution into a DI rinsed (50 ml) Erlenmeyer flask.

As we proceeded to Dissolved Oxygen titration (method 83332), manually (Hand Titration). By sliding Sodium thiosulfate titration cartridge 0.2000 N into the HACH digital titrator model (16900), we slightly turned it to lock the cartridge. Then recapped the titration cartridge and inserted

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