Determination of Free and Total Alkalinity [-OH] in Cleaners
A test kit is available for this titration procedure (see below) or supplies can be ordered individually
Complete Test Kit Part Number: OKT9205-123 (or 45218510)
| Solution-Item | Item | Amount | Part Number | BASF Number |
| Gardotest Indicator 2 | Phenolphthalein | 30 mL | OKT-2246-G | 50560520 |
| Gardotest Indicator 9 | Bromocresol Green | 30 mL | OKT-2207-G | 50560517 |
| Gardotest Indicator 193 | Methyl Red | 30 mL | OKT-2292-G | 50560526 |
| Gardotest Solution 45 | 0.10 N Hydrochloric Acid | 120 mL | OKT-6131-J | 50560590 |
| Gardotest Solution 57 | 1.0 N Hydrochloric Acid | 120 mL | OKT-6130-J | 50560585 |
| Direct Reading Titrator | 0 – 1.0 mL | 1 | OKT-0376 | 45218351 |
| Plastic Dropper | Marked at 1 mL | 1 | OKT-0354 | 45218350 |
| Titration Tube | Marked at 5.0 to 10 mL, with cap | 1 | OKT-0649 | 00000000 |
Note: A couple of articles listed are used for other titrations and are not needed for the procedure.
Refer to the product specific technical information sheet for the appropriate sample size and multiplying factor or ask your technical sales representative
Procedure
|
sing the 1 mL plastic dropper, pipette the appropriate sample volume of bath sample into the empty titration tube. Add distilled water to this solution until the volume is at least 5.0 mL, mark. 2. Add 1 or 2 drops of Gardotest Indicator 2. Swirl to mix. The color will be purple/red. Place the cap on the titration tube. 3. Fill the direct reading titrator to the zero mark with Gardotest Solution 57. 4. Titrate with Gardotest solution 57 by inserting the tip of titrator into the hole of titration tube cap. Slowly dispense the solution while swirling gently. When the color of the sample disappears completely, stop the titration. Record the milliliters of titrant used. Call this Titration A. |
5. Add 1 or 2 drops of Gardotest Indicator 9 to the same solution in the titration tube and mix. The color will be blue. 6. Refill the titrator with Gardotest Solution 57. Titrate as in step 4 until the solution turns from blue through green to a distinct yellow. Record ml. of titrant used. Call this Titration B. CALCULATION Free Alkalinity = A |
Notes:
1. Sample Size: A suggested sample size for highly concentrated alkaline baths is 1 mL and for less concentrated baths, up to 10 mL. An appropriate sample size should yield a Free Alkalinity, or Titration A of about 1 – 2 mL. Once an appropriate sample size is determined, retain it for subsequent titrations for consistency.
2. Use of the Free/Total Alkalinity Ratio: The Free/Total Alkalinity Ratio can be used to monitor and predict the bath life of cleaners which have free alkalinity. A fresh bath of a specific cleaner will always have the same ratio, regardless of concentration. As the bath is used, the ratio will decline. The free/total alkalinity ratio of cleaner baths should be determined at make-up and then weekly. Eventually, the cleaner will lose its effectiveness. At this time, the free/total alkalinity ratio should be noted. Subsequent baths should be discharged prior to reaching this free/total alkalinity ratio.
Example
| A | B | A + B | A / (A + B) | |
| Free Alkalinity | Total Alkalinity | Ratio | ||
| Fresh Bath | 1.75 | 0.25 | 2.00 | 0.88 |
| Used Bath | 1.75 | 0.75 | 2.50 | 0.70 |
| Furhter Use | 1.75 | 1.50 | 3.25 | 0.54 |
SUGGESTION OF OTHER PRODUCTS YOUR COMPANY MAY USE
• CLEANERS
• ETCHANTS
• DEOXIDIZERS
• RUST PREVENTIVES
• METALWORKING FLUIDS (coolants and lubricants)
• WASTE WATER TREATMENT CHEMICALS
• FLOOR CLEANERS AND MAINTENANCE PRODUCTS
• PROCESS EQUIPMENT/CONTROL SYSTEMS
DISTRIBUTED BY NALTIC INDUSTRIALS AN AUTHORIZED DISTRIBUTOR FOR THE USA
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