YSI 9600 - Manual (Page 15)

SULFANILAMIDE – Weigh 15 g of sulfanilamide to the nearest gram and place the solid in a 2 L
graduated plastic bottle. Add 1.5 L of 10 % hydrochloric acid and shake or stir until all of the solid is
dissolved. Using the adjustable pipetter, add 1.5 mL of BRIJ 35 surfactant.
NED – Weigh 1.50 g of N-(1-napthyl)-ethylenediamine dihydrochloride (NED) to the nearest 0.01 g and
place the solid in a 2 L graduated plastic bottle. Add approximately 1.5 L of purified water and shake or
stir until the solid is completely dissolved. Then add 3.75 mL of Photo-Flo 200 and shake well to mix.
NOTE CAREFULLY: The NED reagent is light sensitive and the storage bottle should be either
kept in the dark or covered with some material, e.g., aluminum foil, to prevent premature
degradation.
WASH – Place 1.5 L of water in a 2 L graduated plastic bottle. Add 3.75 mL of Photo-Flo 200 and shake
well to mix.
CAUTION: It is CRITICAL for proper operation of the 9600 for the Photo-Flo 200 to be included in
both the NED and Wash reagents. Do not attempt to deploy without adding the Photo-Flo to these
solutions.
1000 MG/L NITRATE-NITROGEN STANDARD – Weigh 7.22 g of potassium nitrate to the nearest
0.01 g and quantitatively transfer the solid to a 1000 mL volumetric flask. Add approximately 500 mL of
purified water and swirl the mixture until the solid is completely dissolved. Then add additional water to
fill the flask to the top graduation mark. Mix well by repeated inversion of the flask. Transfer the
standard to a dry 2-L plastic bottle for storage. YSI recommends that this standard be stored in a
refrigerator and then warmed to ambient temperature prior to use. If refrigerated, the standard will be
stable for approximately 3 months.
VARIABLE NITRATE-NITROGEN STANDARDS – Nitrate-nitrogen standards in various
concentrations can be prepared by diluting the 1000 mg/L standard prepared in the section above. Using
this method, accurate aliquots of the concentrated standard are transferred to the 1000 mL volumetric flask
and then the flask is filled to the top graduation mark and inverted repeatedly to assure good solution
homogeneity. Examples of the amount of 1000 mg/L standard to dilute to 1000 mL are shown in the Table
below:
Final Nitrate-N Standard Conc Amount of 1000 mg/L Standard Final Volume
6 mg/L 6.00 mL 1000 mL
4 mg/L 4.00 mL 1000 mL
2 mg/L 2.00 mL 1000 mL
1 mg/L 1.00 mL 1000 mL
0.50 mg/L 0.50 mL 1000 mL
0.20 mg/L 0.20 mL 1000 mL
0.10 mg/L 0.10 mL 1000 mL
NOTE: Users can also purchase 1.0 mg/L nitrate-N standard from YSI in 500 mL quantities as Model
Number 3885.
SELECTING A NITRATE STANDARD CONCENTRATION – For your initial deployment using
either a 9600-02 (2 mm detector cell) or a 9600-10 (10 mm detector cell), YSI recommends using a
standard that is 1mg/L in nitrate-nitrogen (nitrate-N). This standard will assure readings that are accurate
to 5 % of the reading or 0.2 mg/L whichever is greater, with the 9600-02 and 5 % of the reading or 0.02
mg/L, whichever is greater, with the 9600-10. Once you obtain more information about the typical high
and low limits of nitrate concentration at a particular site, you might want to use standards of different
values to maximize accuracy. For example, with a 9600-02, if the water at your site is known to
YSI Environmental 15 Model 9600 Nitrate Monitor