A. Reagents and Equipment
Vendor
|
Vendor
|
Catalog #
|
Price
|
Shelf life
|
| SulfaVer® 4 Sulfate Reagent, 5 mL |
Hach |
2106769 |
$28.95 for 100 tests |
|
| Sulfate standard, 1000 ppm |
Labchem |
LC255101 |
$33.20 for 500 mL |
24 months |
| Distilled water |
|
|
|
|
B. Sulfate-Hach Calibration Curve
- Dilute the 1000 ppm sulfate standard as outlined in the Table below:
Tube |
Sulfate Concentration
(ppm)
|
Volume of 1000 ppm standard (mL)
|
Volume of distilled water (mL) |
| 1 |
0.00 |
0.00 |
10.0 |
| 2 |
37.5 |
0.375 |
9.625 |
| 3 |
75 |
0.75 |
9.25 |
| 4 |
112.5 |
1.125 |
8.875 |
| 5 |
150 |
1.5 |
8.50 |
| 6 |
187.5 |
1.875 |
8.125 |
| 7 |
225 |
2.25 |
7.75 |
| 8 |
262.5 |
2.625 |
7.375 |
| 9 |
300 |
3.0 |
7.0 |
- To each 10 mL sample, add the contents of one SulfaVer 4 Sulfate reagent, shake and let stand. Below is an image of all of the calibration solutions after adding the powder reagent.
- Transfer approx. 1mL of each calibration solution to a cuvette.
- In the colorimeter plotting program, select the green LED and ppm as units. Calibrate the colorimeter with the 0 ppm sulfate solution and measure absorbance of all of the solutions in duplicate or triplicate.
Results
Calibration curve measurements were repeated three times. Data for the three separate calibration trials were compiled into one file which is attached at the bottom of the page (sulfate_hach.txt). To view this data, download the file and open in the colorimeter plotting software as described here. The final plot for all three sets of data is shown below:
|
 Updating... Joanne Long, Jun 12, 2013, 3:17 PM
|
