PH In Caustic

Question 1

2. Intro to Instrument

Answer 1

• Press and hold power key for 3 sec to turn on/off.
• meter on, press and quickly release power button to vary intensity of backlight
• instrument should be run on single channel view and not split channel screen.

Question 2

3. Electrode preparation

Answer 2

• check electrode plug should be in place when electrode not in use. Open plug to begin analysis
• check level of filling solution in electrode. Should be above coils but not over opening for plug. If level low, add Ross Reference Electrode Filling solution so it is above the coils
• Check junction to be sure there are no salt deposits present. If so, rinse with DI water and blot electrode
• electrode designed to leak at rate of 1mL per 24 hrs. Keep unction from clogging, the leak rare is higher than conventional electrode
• can wet junction by pressing down on electrode cap so few drops of ROSS filing solution flow out of electrode
• shake electrode downward to remove air bubbles
• replace fill plug once analysis complete

Question 3

4. pH buffer solutions

Answer 3

• change solutions once a week, good idea to change on Friday before calibrating
• instrument should be calibrated using two-point calibration. Usually samples being analyzed will fall within 7.0-10.0 pH range
• start with Standard 1 being 7.00 and 2 being 10.01
• if samples fall below 7.00, must recalibrate using 4.01 as standard 1 and 7.00 as standard 2.

Question 4

5. Thermo scientific/Orion meter operation and calibration

Answer 4

• verify you are on Channel 1-pH. Begin calibrating by selecting F2
• stirrer should be turned on so buffer or sample can stir at slow rate of speed
• electrode should be rinsed with DI water and blotted dry using lint-free tissue. Never rub or wipe electrode bulb to reduce chance of error due to polarization
• place electrode in electrode holder in pH buffer 7.00 solution and press start
• when number stabilizes enter correct buffer value then hit next and do same for second buffer. Hit log/print when calibration complete

Question 5

6. Sample analysis using thermo pH meter

Answer 5

• if sample from HF Alky unit, test using red litmus paper: stays red acid, turns blue it is basic or caustic
• if sample acidic, contact supervision before further testing
• pour sample jn beaker. Never pH a sample directly in the bottle. Sample should always be stirred (at 4-5 rate)
• standards and sample should be close to same temp since no temp probe
• filling hole always open during measurements and filling solution level should be higher than level of sample
• when display reads ready, record pH to two decimal places (do not record pH greater than 14, it is 14.00 if it is higher

Question 6

7. Troubleshoot

Answer 6

• can drain ROSS solution and place fresh in probe if probe acting weird.
• there is RICCA 7.00 pH solution available to check instrument. It can be checked out from stockroom and should run 6.50 to 7.50 to verify instrument is fit for use. Should check this periodically

Question 7

1. Purpose

Answer 7

Ph is used in water treating to determine intensity of acidic or basic nature of a sample. Alkalinity and acidity are the acid and base neutralizing capacities of water. It is measured using electrode which measures the activity of hydrogen ions, pure water is neutral and has pH of 7.0 solutions with pH less than 7 are acid and with greater than 7 basic, alkaline or caustic. pH scale ranges from 0-14