YSI 9600 - Manual (Page 90)

Can I use the 9600 to measure nitrite (NO2
-
)?
Yes. The 9600 will measure the nitrite in the water if the cadmium column is removed and its inlet and
outlet ports are connected by a fitting that is provided with the instrument. In fact, with the cadmium
column in place, the 9600 measures the sum of the nitrate AND nitrite in the water being monitored.
Normally, however, because of nitrification, there is very little nitrite in most environmental water and
therefore the 9600 reports its readings as nitrate. Users who are concerned that there is indeed a significant
quantity of nitrite in the water at their monitoring sites should either carry out studies with the 9600 with no
cadmium column in place or should collect water samples at the site and perform laboratory analyses for
nitrite to confirm that its presence is having a significant effect on the overall accuracy of the measurement.
CHEMICALS AND SAFETY
What safety concerns need to be addressed when using the 9600?
There are three major areas of concern when using the 9600:
• Operation of the YSI 9600 Nitrate Monitor requires the use of a variety of chemicals and users must
take care to handle them properly. With one exception (elemental cadmium), the user is required to
purchase these chemicals from a vendor of their choice. Users should consult the Material Safety
Data Sheets (MSDS) supplied by these vendors for all reagents before their use and should follow
manufacturers’ and/or MSDS recommendations with regard to their proper disposal. Users should
ALWAYS wear appropriate protective equipment including safety glasses with side shields and gloves
when handling any of these chemicals.
• For proper operation of the YSI 9600, cadmium metal MUST be purchased in packaged form as the
YSI Model 9612 Cadmium Column Assembly. An MSDS for the material captured in the cadmium
column is automatically supplied to the user by YSI. To protect against potential hazards associated
with inhalation of cadmium dust, the cadmium column should be handled in a fume hood during
activation. After the reducing capacity of the cadmium column has been exhausted, the entire sealed
column should be disposed of in accordance with regulatory requirements, e.g. hazardous waste.
Users should NEVER open the cadmium column in attempts at regeneration. If the cadmium is
accidentally spilled, appropriate spill measures should be taken.
• The waste generated from use of the YSI 9600 contains potentially toxic organic chemicals, but most
importantly, contains Cd
2+
that according to the USEPA is toxic and a probable human carcinogen.
Users should NEVER discharge waste from the YSI 9600 into the environment, instead retaining it in
the waste bags that are provided with the instrument. Likewise, unless specifically approved by the
local wastewater authority, users should NEVER dispose of the reaction waste into a sanitary or storm
sewer. The waste should be disposed of in accordance with regulatory requirements with an approved
waste handler.
While these concerns are significant, they basically involve commonly-used good laboratory practices that
are used by many organizations already. While the cost of disposal of the waste through a certified waste
handler will vary somewhat, it generally it is not so high as to be a major factor in the overall cost of
monitoring nitrate with the 9600. The key is that you WILL have to handle chemicals if you use a 9600
and you should have a plan in place to do so before you purchase the instrument.
Where do I get the chemicals to use with the 9600?
The sources used for the various reagents that have been used in YSI development studies on the 9600 are
provided in detail in the 9600 manual. However, other than cadmium, users can purchase reagents from
YSI Environmental 90 Model 9600 Nitrate Monitor