Hach DR/850 Procedures Manual page 426

TANNIN AND LIGNIN,
9.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0.0 mg/L tanic
Sampling and Storage
Accuracy Check
Method Performance
continued
10.
Place the prepared
sample into the cell
holder. Tightly cover the
sample cell with the
instrument cap.
Collect samples in clean plastic or glass bottles.
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.
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.
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).
426