|
Introduction
Alkalinity measurement is important in the control of water and wastewater treatment. In a sample, alkalinity is defined as the quantitative ability to react with (neutralize) a known quantity of standard acid. Many commonly occurring materials, such as carbonate, bicarbonate, phosphates, and hydroxides, increase alkalinity in natural waters.
Conventional Ways to Measure Alkalinity:
Alkalinity is measured commonly by titration, using either a buret or "drop count" technique. A sample is titrated with an acid solution which neutralizes the alkaline species present. The endpoint is determined by observing a color change or by titrating to a pH value of 4.5, using a pH electrode as an indicator. The volume of titrant required to change the color or to reach the endpoint is then used to calculate total alkalinity.
Both methods have limitations. Sample color or turbidity affects the operator's ability to detect the color change. Use of a buret or stopper is tedious and time-consuming.
Fast and Easy Alternative:
The Orion Total Alkalinity Test Kit simplifies routine alkalinity measurement. Save time by eliminating additional equipment set-up, tedious titrations and calculations. The Orion Test Kit is ideal for field use. Results are unaffected by sample color or turbidity, and the kit does not require tedious drop counting.
- Direct reading 0-225 ppm as CaCO3
- No titration
- No special equipment
- No interferences from color or turbidity
- Ideal for field determinations
How Does the Orion Test Kit Work?
The principle of operation for the Orion Test Kit is the same as the conventional titration. A reagent composed of several acids reacts with the alkaline species in the sample. As a result, the pH of the sample changes. The observed pH reading after the addition of the reagent varies directly with the total alkalinity (See Figure 1). Each pH reading corresponds to a unique value for alkalinity, expressed in ppm CaCO3.
Using your own pH electrode and pH meter, measure total alkalinity directly. Just calibrate for pH as usual, add the Orion Total Alkalinity Reagent and read total alkalinity in ppm CaCO3 from the conversion chart included in the kit.
OBSERVED pH:
4.5
4.45
4.40
4.35
4.30
4.25
4.20
70 80 90 100 110
ppm CaCO3
Figure 1:
Orion Total Alkalinity Test Kit
Observed pH vs. ppm CaCO3
Total Alkalinity Test Kit Instructions:
Find expected sample concentration range in chat below and use the indicated volumes of sample and Total Alkalinity Reagent. If pH of sample prior to reagent addition. Follow instructions below for measurement of total alkalinity.
- Range Sample Volume Reagent Volume Chart Side (Blue/Gray) Accuracy
- Low level 0-25 ppm 100 mL 1 mL Blue ±0.5 ppm
- Full 0-225 100 mL 10 mL Gray ±5 ppm
- Greater Than 225 10 mL diluted to 100 mL with distilled water 10 mL Gray (multiply results by ten) ±5 ppm
1. Calibrate pH electrode and meter using pH 7 and 4 buffers, according to the manufacturer’s instructions
2. Using pipet or graduated cylinder, measure 200 mL sample into beaker.
3. Pipet appropriate amount of Total Alkalinity Reagent into sample and mix well. (See chart)
4. Measure resulting pH of sample
5. Using indicated side of Total Alkalinity Conversion Chart, find resulting pH value and read total alkalinity of sample in ppm CaCO3. Measure total alkalinity standard/control every 10 samples or daily as a verification of measurement. See Use of Total Alkalinity Standard/Control.
Use of Total Alkalinity Standard/Control
Use Total Alkalinity Standard/Control daily, or after every ten samples for verification of proper measurement.
- Expected Sample Conc. Standard Volume Reagent Volume Expected pH Value
- 0-25 ppm 1 mL 1 mL 4.64 ±0.05
- 0-255 10 mL 10 mL 4.41 ±0.05
1. Carefully pipet appropriate volume of 1,000 ppm standard/control into a clean 100 mL volumetric flask and dilute to mark with deionized water.
2. Transfer into a clean beaker and add appropriate volume of Total Alkalinity Reagent, mix well.
3. Calibrate pH electrode and meter using pH 7 and 4 buffers as usual.
4. Measure pH of control. See chart for expected values.
If pH value of control is not within the range:
1. Recalibrate pH electrode and meter using fresh buffers. Slope should be 92-102%
2. Prepare fresh control.
3. Check alkalinity of deionized water. Any alkalinity in the water used for diluting will contribute to the total alkalinity measured in the control:
- Measure total alkalinity of the deionized water, using low-level procedure, and multiply result by 0.9. This value, AH2O, is the contribution to total alkalinity from the deionized water.
- Carefully pipet 10 mL of 1,000 ppm standard/control into a clean 100 mL volumetric flask, dilute to mark with deionized water, and mix well.
- Transfer into clean beaker and add to mL of Total Alkalinity Reagent and mix well.
- Measure pH of solution, and using gray side of conversion chart, read total alkalinity, A.
- Determine alkalinity of control, Ac:
- Ac = A-AH2O
- Value should be 100 ±5ppm.
Ordering Information:
Orion Total Alkalinity Test Kit Cat. No. Description:
- 700010 Total Alkalinity Test Kit includes:
Total Alkalinity Reagent, one 475 mL bottle; Alkalinity Standard/Control, one 475 mL bottle; Total Alkalinity Conversion Chart. Average of 80 tests per kit.
- 700011 Total Alkalinity Reagent Refill, four 475 mL bottles
- 700012 Alkalinity Standard/Control, 475 mL bottle
- Other Orion Test Kits and Water Methods
- Pure Water pH Test Kit
- Improves reproducibility
- Improves accuracy
- Fast response
- Less noise
Here's a test kit specifically designed for measuring pH in samples of low ionic strength, typically: rain water, boiler water, and some natural and municipal waters.
Nitrate Test Kit
- Eliminates chloride and other anion interference
- No filtering of samples required
- Low cost per sample
- Now, to key measurements, NH3 and No3-, can be done with one electrode
Easy to use, this test kit is recommended for nitrate measurement in soils, or other sample with high chloride or carbonate content.
Thermo Scientific has compiled many electrode methods for water and wastewater determination. Examples include:
- Acidity And Alkalinity Of Water By Titration
- Ammonia In Water And Wastewater
- Calcium In Water
- Carbon Dioxide OR Carbonate In Water
- Chloride In Drinking Water, Wastewaters, And Brines
- Copper In Natural Waters
- Cyanide By electrode Indicator Method
- Cyanide In Water And Wastewater
- Dissolved Oxygen In BOD Measurement, Water And Wastewater
- Fluoride In Drinking Water
- Low-Level Fluoride
- Nitrate In Drinking Waters
- Nitrate In Environmental Samples
- Nitrate In Waters
- pH In Pure Water
- Sodium In Water
- Sulfate In Waters By Titration
- Sulfide In Waters
- Total Kjeldahl Nitrogen In Waters and Wastewaters
- Total Residual Chlorine In Waters
- Water Hardness
Applications assistance is available from our full-time group of technical service chemists, either over the phone or in-site. They are dedicated to answering your questions and helping you with your analytical problems. |
7 Artikel Summe 6,748.00 USD 