Hach DR/850, Procedures Manual, Page: 388 / 460

388
Sampling and Storage
Collect samples in clean plastic or glass bottles that have been
cleaned with 1:1 Hydrochloric Acid Solution and rinsed with
deionized water. Do not use a commercial detergent containing
phosphate for cleaning glassware used in this test.
5.
Add 1 mL of Amino
Acid Reagent Solution.
Cap and invert several
times to mix (the
prepared sample).
Note: A blue color will
form if phosphate is present.
Note: You may substitute
the contents of one Amino
Acid Reagent Powder
Pillow for 1 mL of Amino
Acid Reagent Solution.
6.
Press:
TIMER ENTER
A 10-minute reaction
period will begin.
Note: Perform Step 7 while
the timer is running.
7.
Pour 25 mL of
sample (the blank) into a
sample cell.
8.
When the timer
beeps, the display
will show:
mg/L PO4
Place the blank into the
cell holder. Cover the
sample cell with the
instrument cap.
9.
Press:
ZERO
The cursor will move to
the right, then the
display will show:
0.0 mg/L PO4
Note: If Reagent Blank
Correction is on, the
display may flash “limit”.
See Section 1.
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 PO
4
will
be displayed.
Note: Standard Adjust may
be performed using a
prepared standard (see
Section 1).
PHOSPHORUS, REACTIVE,
continued