Hach DR/850, Procedures Manual, Page: 426 / 460

426
Sampling and Storage
Collect samples in clean plastic or glass bottles.
Accuracy Check
Standard Solution Method
Prepare a 200-mg/L tannic acid standard solution by dissolving
0.200 grams of tannic acid in deionized water and diluting to
1000 mL. Prepare this solution monthly. A 2.0 mg/L tannic acid
standard is prepared by diluting 10.00 mL of the stock solution to
1000 mL with deionized water. Prepare this standard daily.
Method Performance
Precision
In a single laboratory, using standard solutions of 4.0 mg/L tannic
acid and two representative lots of reagent with the instrument, a
single operator obtained a standard deviation of ±0.1 mg/L tannic
acid.
Estimated Detection Limit
The estimated detection limit for program 98 is 0.1 mg/L tannin
and lignin. For more information on the estimated detection limit,
see
Section 1 .
9.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0.0 mg/L tanic
10.
Place the prepared
sample into the cell
holder. Tightly cover the
sample cell with the
instrument cap.
11.
Press:
READ
The cursor will move to
the right, then the result
in mg/L tannic acid will
be displayed.
Note: Standard Adjust may
be performed using a
prepared standard (see
Standard Adjust in Section 1).
TANNIN AND LIGNIN,
continued