Nitrate High Range Test for Hach 850/890 and Hach DR 2000/2800

Method Number 8039

1.  Turn on all four HACH 850/890 instruments and press PRGM > 51 > ENTER.

2.  Samples will be poured into the pre-cleaned blue capped centrifuge tubes marked with a N at the fill station.  Pour each sample into two pre-cleanced glass sample cells up to the 10 ml mark.  Cap one and set it aside to serve as your blank.  Write sample numbers with a pencil on the white triangles on the sample cells, making sure to mark one as a blank (for example, 1B and 1 for the first sample.)

3.  In the second sample cell add the contents of one NitraVer 5 Nitrate Reagent Powder Pillow.  Be sure to get all of the powder out of the packet, especially from the corners.  Screw the cap on the cell.

4.  Shake the sample cell vigorously for 1 minute. 

-  This can be timed by using the timer provided on the station table.

-  It is important to shake the sample cell vigorously

 and constantly for the entire minute to allow the reagent to dissolve.

 Not doing so will impact the results.

5.  After the one minute is over, set the sample cell down and allow a 5-minute reaction time.

-  This can be timed by using the timer provided on the station table.

- A black precipitate may form on the bottom of the cell.  This is normal and will not affect the results.

6.  While reaction is occurring, wipe down the blank and the sample cells with an alcohol swab and then a Kimwipe to remove finger prints and liquid.

Hint:  You may begin the next sample during this 5-minute reaction time when you

are comfortable with the procedure.

7.  After the 5-minute reaction is complete, place the blank into the cell holder and cover tightly with the cap.  Press ZERO.

8.  Place the prepared sample in the instrument, cover tightly, and press READ.         

THIS TEST IS VERY TIME SENSITIVE, READ RESULTS AS QUICKLY AFTER REACTION TIME AS POSSIBLE. 

After results are displayed, press CONC. 

Doing so will change the display between

NO₃-N and NO₃ near the bottom of the screen.

Record the NO₃-N value.

9.  Repeat steps 7&8 with all other colorimeters.

10.  The samples will also be tested in the DR 2800 spectrophotometer. 

            -From the Main Menu, choose Stored Programs.

            -Choose to type in the program, type 355 and hit OK.

-Put the blank sample cell in with the fill line facing left, cover with protective cover,            and press Zero.

-Put the prepared sample cell in with the fill line facing right, cover with protective cover, and press Read.  Record this value.

11.  Discard liquid wastes in the designated disposal container.  Clean the sample cells thoroughly with a test tube scrubber to remove all particles.  Rinse the used sample cells three times with deionized (DI) water before re-using them for the next samples.  When finished, place used sample cells into the plastic tub labeled USED NITROGEN GLASSWARE.