YSI 9600 - Manual (Page 16)

consistently contain concentrations of nitrate higher than 6 mg/L, then users might consider employing a
higher standard concentration such as 6 mg/L nitrate-N. For many estuarine and near coastal studies,
where nitrate concentrations may always be below 0.5 mg/L nitrate-N, the use of a 0.2 mg/L standard will
probably improve the data accuracy. Note, however, that YSI does not recommend using standards less
than 0.1 mg/L of nitrate-N.
CAUTION: Use of standards with concentrations higher than 8 mg/L of nitrate-N may compromise the
accuracy of the 9600.
NOTE: The procedure noted above for the variable nitrate-nitrogen standards will have to be carried out
multiple times in order to generate enough standard to fill the two reagent bags as described below.
Alternatively, a larger volumetric flask can be used in the preparation as long as the amount of 1000 mg/L
standard shown in the table is increased appropriately.
After preparing the reagent solutions, be sure to label each storage bottle appropriately.
BLANK– The blank is typically purified water which has a salinity which is roughly that of the water at
the site for brackish and oceanographic applications and simply deionized or distilled water for freshwater
applications.
2.4 FILLING THE REAGENT BAGS
Under deployment conditions, chemical reagents are fed into the FIA system of the Model 9600 from
collapsible reagent bags that you unpacked and set aside in Section 2.1 above. Thus, to operate the nitrate
monitor, you must transfer solutions from the storage bottles to the bags prior to each deployment. The
bags are nominally 1 L, but will in fact require approximately 1.2 L of solution for complete filling and
maximum deployment times.
CAUTION: Be sure to wear appropriate protective equipment including safety glasses and gloves
while filling the reagent bags. In addition, be certain to point the reagent bag fittings away from
your face when you are expelling air from the bag through the partially-open fittings as described
below.
NOTE: The reagent bags are color-coded to match the threaded fittings on the nitrate monitor tubing to
facilitate installation. Be sure to put each reagent in the proper color-coded bag according to the
information in the table below:
REAGENT BAG COLOR
Standard – 2 bags White
Blank – Purified Water Black
Buffer Blue
NED + Photo-Flo 200 Red
Sulfanilimide + BRIJ Yellow
Wash – Purified Water + Photo-Flo 200 Green
It may also be prudent for the user to label each bag with a “magic marker” prior to filling.
NOTE: For the Predeployment Check of the analyzer as described in Section 4.2 below, you will need
TWO 1 liter bags filled with your standard solution. Note that you have been furnished with two
bags labeled with a white tie-wrap, one of which has a tubing assembly attached.
YSI recommends that the method outlined below be used to fill each of the reagent bags:
YSI Environmental 16 Model 9600 Nitrate Monitor