1. Determination of HF Acid Strength and Water Content
Area
Unit
Operating Procedure #
Certified by
Revision #
Date
Page 3
Lab
OPS-LB-NM-036
R. Guidry
3/22/11
1 of 4
Job Hazards
Yes
Access and Egress Y
Moving Parts
Activities of Others
Noise
Adverse Weather
Rail Movement
Chemical Exposure
Sharp Edges
Electricity
Slips, Trips, and Falls
Fatigue
Static Electricity
Fire and Explosion
Trip Injuries
Ground Contamination
Trapped Pressure
Manual Handling
Working at Height
Other:
References / Documents
Appendix 1: Materials and Reagents
SSP-0023A
SSP-0023B
UOP #
PPE
Use
Standard (SSP-0011) Y
Full Face Shield / Goggles
Hood
Clothing—Chemical Protection
Gloves—Chemical
Personal Fall Protection
Respirator / Filter Mask
Supplied Air
Special Instructions
N/A
Environmental
N/A
W A R N I N G
Quality Assurance
N/A
C A U T I O N
Determination of HF Acid Strength and Water Content
WARNING: Neoprene gauntlets must be worn over protective gloves at all times when handling materials used for HF analysis. Full face shield and vinyl jacket must be worn at all times while dispensing HF acid. 1
Turn on power to hot plate (250 ml beaker with 100 ml of mineral oil should already be placed on hot plate). 2
Weigh 2 clean, labeled 500-ml and 125-ml plastic bottles w/caps. Record weights. 3
Pour into the 500-ml bottles enough DI water for the weight of each to be 380 g (+/- 15 g). Reweigh and record weights. 4
Place each of the 2 bottles with water in 1000-ml beakers. Add sufficient ice to entirely surround the containers. Place layer of ice on the bottom of ml beakers and place the empty 125-ml bottles on layer and add ice as before. 5
Allow approximately 20 minutes for bottles to chill. 6
Retrieve the HF acid sample containers. Containers should have a red tag (indicating that the container has HF acid in it) and clearly display the reactor number. 7
Under exhaust hood with the capped end facing away from you, ensure valve is closed and unscrew cap from cylinder labeled Rx 1. 8
Rinse sample container and cap with acetone, then dry. 9
Screw on the delivery tube to the container and tighten. 10
Securely fasten sample container onto stand using clamps.
CAUTION: Smaller bottles used for % water determination must always be filled first in order to avoid contamination of water from larger bottles. 11
Uncap 125-ml plastic bottle labeled 1; place entire beaker (with bottle in ice) so that delivery tube is submerged inside bottle (use blocks to elevate beaker). 12
Carefully open valve of sample container and dispense sample until ½” layer of sample is in bottle and close off valve to sample container.
q Procedure Completed
Date:
Prepared By:
Approved By:

2. Determination of HF Acid Strength and Water Content (continued)
Area
Unit
Operating Procedure #
Certified by
Revision #
Date
Page 3
Lab
OPS-LB-NM-036
R. Guidry
3/22/11
2 of 4
Determination of HF Acid Strength and Water Content (continued) 13
Remove beaker with bottle from wooden blocks, replace cap tightly onto bottle. 14
Uncap 500-ml plastic bottle (labeled 1) and with the use of blocks, insert the delivery tube below the surface of the water. 15
Carefully open valve of sample container to obtain at least 10 grams of sample and close valve. Remove beaker with bottle from blocks and replace cap. 16
Repeat steps 7 – 15 for cylinder and bottles corresponding to Rx 2. 17
Remove the 125-ml plastic bottles with sample from ice and wipe dry. Reweigh bottles and record weight. 18
Under hood with bottle cap angled away from you, remove cap from each of the small bottles and replace with similar cap with ¼“ hole and place each in beaker with mineral oil on pre-warmed hot plate for 1 hour.
WARNING: Face Shield and Vinyl Jacket may be removed after Step 19, however, Gloves and Safety Glasses must be worn at all times throughout testing. 19
Remove 500-ml bottles with sample. Thoroughly wipe dry, reweigh bottles and record weights. 20
Add additional aliquot of approximately 20 – 30mls DI water to bottles (until about 1 inch from the top of container). 21
Reweigh bottles and record weights. 22
Shake bottle #1 until acid and water are well mixed then pour 10 to 15 grams of solution (solution should not quite cover stir bar) into a plastic beaker with stir bar. Reweigh bottle and record weight. 23
Add approximately 75 ml of DI water along with several drops of phenolphthalein soln. to beaker. 24
Titrate sample using 1.0 N NaOH until pink endpoint which persists for 30 seconds. 25
Repeat Steps 22 – 24 for bottle #2. 26
Calculate HF acid strength as follows: % HF = 2*(ml of NaOH needed for titration)* (A/B) C
Where:
A = Difference in weight between the empty 500-ml bottle (Step 2) and bottle with sample and total water (Step 21)
B = Difference in weight between Step 3 and Step 19
C = Difference in weight between Step 21 and Step 22 27
After 1 hour, remove small bottles from hot plate, replace original caps and thoroughly wipe bottles. 28
Ice down the bottles in the beakers as before, taking care not to introduce moisture into the bottles. 29
Turn on power to Karl Fisher titrator.
q Press “Stirrer Speed” button, then “4”.
q Press the button to start stirrer.
q Press the “TITR CURRENT” button to count out any moisture present in the system.
q Procedure Completed
Date:
Prepared By:
Approved By:

3. Determination of HF Acid Strength and Water Content (continued)
Area
Unit
Operating Procedure #
Certified by
Revision #
Date
Page 3
Lab
OPS-LB-NM-036
R. Guidry
3/22/11
3 of 4
Determination of HF Acid Strength and Water Content (continued) 30
Allow bottles to cool for 15 – 20 minutes. 31
Under hood, uncap bottle #1. 32
Angling bottle away from face, pipet 20 ml of pyridine into sample. Pipet tip should rest at an angle on inner wall of bottle to prevent bumping from reaction of acid with pyridine. 33
Replace cap and return bottle to ice bath. 34
Repeat Steps 31 – 33 for bottle #2. 35
Wait a couple of minutes, then vent samples ensuring bottles are directed away from face. 36
Determine moisture for reagent blank as follows:
q After flushing several times, draw 0.2 ml pyridine into syringe.
q Puncture needle of syringe through septum of titrator ensuring needle does not touch liquid in reservoir.
q Press “START/STOP” button.
q Display will read “ADD SAMPLE”.
q Lower needle to inject sample blank into liquid.
q Wait for reading to display once analysis is completed (Display will flash “READY”).
q Record moisture reading for blank. 37
Remove bottle #1 from ice and wipe dry. 38
Swirl sample and pyridine to ensure well mixed and analyze 0.2 ml of this mixture as before. Record number. 39
Repeat Steps 37 – 38 for bottle #2. 40
Perform the following calculation for each sample to determine water content:
% H2O = (Counts of sample mixture – Counts blank)/sample weight x 100. 41
Turn off titrator.
Clean Up After Analysis 1
Add ice to the plastic waste container kept under hood. 2
With sample cylinder clamped on stand, place the tip of delivery tube below the ice and insert blocks under plastic container. 3
Slowly turn valve to empty HF acid into ice.
CAUTION: HF will react vigorously when dispensed into ice. 4
Once cylinder has been emptied, valve is turned to fully open position. 5
Pour approximately 250-ml acetone into beaker.
q Procedure Completed
Date:
Prepared By:
Approved By:

4. Determination of HF Acid Strength and Water Content (continued)
Area
Unit
Operating Procedure #
Certified by
Revision #
Date
Page 3
Lab
OPS-LB-NM-036
R. Guidry
3/22/11
4 of 4
Clean Up After Analysis (continued) 6
Remove cylinder from stand and unscrew delivery tube. 7
Pour acetone into cylinder and close valve. 8
Invert cylinder several times to allow the acetone to clean the inside walls. 9
Place cylinder back on the stand and open valve of container all the way to drain acetone in plastic container.
CAUTION: Waste material is poured into a plastic one gallon bottle for disposal in the Alky unit. 10
After draining cylinder completely, apply vacuum to opening to remove any moisture still present. 11
Keep valve open and wipe cylinder clean. 12
Screw on cap to cylinder and attach white tag on container labeled “Clean & Dry”. 13
Repeat Steps 1 – 12 for remaining cylinder. 14
Empty all plastic sample bottles into the one gallon plastic bottle for disposal and rinse bottles out with small washings of acetone. 15
Add acetone to plastic bottles, shake well and allow to stand overnight.
q Procedure Completed
Date:
Prepared By:
Approved By:

5. Determination of HF Acid Strength and Water Content (continued)
Area
Unit
Operating Procedure #
Certified by
Revision #
Date
Page 3
Lab
OPS-LB-NM-036
R. Guidry
3/22/11
App. 1
Appendix 1: Materials and Reagents
300-ml Columbia LT-50 Monel® Cylinders
Aquatest cma Karl Fischer Coulometric Titrator
Buret, 25-ml
2 500-ml Nalgene® bottles (labeled 1 and 2)
2 125-ml Nalgene® bottles (labeled 1 and 2)
ml glass beakers
2 500-ml glass beakers
1 N NaOH soln.
Anhydrous Pyridine
Phenolphthalein Soln., 1% in 50% IPA
Reagent grade Acetone
Mineral Oil
Pipet, 20-ml Volumetric (borosilicate glass)
Rubber Bulb Pipet Filler
1-ml Disposable Syringe with 3 ½ “ needle
Hot Plate ( ºF)
Balance
q Procedure Completed
Date:
Prepared By:
Approved By: