|
2.0 Nitrate Test Kit (NTK) FAQ
2.1 Q: What are NECi NTK
products?
2.1 A: NECi produces and sells NTK
products for quantitatively testing the nitrate content of water and
water-based extracts of food, plants and soils. NECi NTK systems are all
designed to be easy to use in a very reliable manner to get the best
results with the safest and most environmentally friendly reagents
available in any commercial nitrate test kit on the market today!
2.2 Q: How do your kits work?
2.2 A: Enzymes are biodegradable
proteins, safe for the user and the environment. The enzyme used in our
Nitrate Test Kits and Reagents is a purified form of Nitrate Reductase
(NaR). The NaR reaction is diagrammed like this:
NADH + NITRATE → NITRITE +
NAD+ + OH-
NADH (nicotinamide adenine dinucleotide)
is a derivative of a B vitamin. Other test kits use the toxic metals
cadmium or zinc for this step. A few competitors use a different form of
NaR that requires more expensive NADPH as its cofactor. NECi’s NaR is
more stable. The resulting nitrite reacts with Color Reagents (the Griess
Reaction) to form a pink color easily detected by eye or by a photometer
at 540nm ± 10nm. In Home, Ag, and Environmental kits, you’ll compare the
color to that of the nitrate standards (supplied with each kit) to
determine the nitrate content of your samples.
2.3 Q: How do I choose the
best kit for me?
2.3 A: Choose a standard range NTK if you
expect your nitrate levels to be between 1 and 10 ppm nitrate-N, choose a
low range kit if you expect your nitrate levels to be below 1 ppm
nitrate-N. If you are not sure, choose a low range kit and if your
nitrate levels are too high you can dilute the samples to bring them down
to range.
Consumer kits are for fast and
simple water tests at home and require no equipment or chemistry
experience.
Agricultural kits are for
plant or soil extracts, or for surface water samples which may be turbid
or dirty. They also require no equipment or chemistry experience.
Environmental field kits are
for multiple water samples. No equipment necessary but some chemistry
experience a plus. (CD-Rom instructional video also available).
Lab kits are for the demanding
user with access to laboratory equipment and extensive chemistry
experience.
2.4 Q: What are the nitrate
sensitivity ranges of NECi NTK systems?
2.4 A: The user can choose to analyze
nitrate in the Standard Range of 0.5 to 10 ppm nitrate-N
or the Low Range of 0.01 to 1.0 ppm
nitrate-N. Since NECi NTK systems all use a photometric method for
evaluating the nitrate content of your samples, the results are highly
accurate.
2.5 Q: What are the advantages
of NECi NTK products over other commercial methods for nitrate analysis?
2.5 A: Most other commercial nitrate
analysis methods use a heavy metal such as cadmium or zinc for reducing
nitrate to nitrite. Heavy metals, especially cadmium, are toxic. So using
nitrate analysis systems dependent on cadmium present a health risk for
both the person doing the analysis and for the environment since cadmium
is difficult to dispose of. NECi NTK systems which use natural NaR and
NADH for nitrate analysis are both safe for the user and the environment.
Since NECi NTK systems are as accurate, if not more accurate, than other
commercial systems, NaR/NADH based systems are a better choice.
2.6 Q: What type of samples
can be analyzed with NECi NTK systems?
2.6 A: NECi NTK products are designed to
be used for nitrate analysis in water and other aqueous samples such as
extracts of food, plants and soil. Non-aqueous solvents will interfere
with the enzyme catalyzed reaction and must not be used with NECi NTK
systems.
2.7 Q: Can I use turbid or
"colored" samples with NECi NTK systems?
2.7 A: Yes, but only in the Standard
Range NTK systems where the sample volume is small. To analyze turbid
samples in the Low Range NTK series, the sample must be filtered and/or
centrifuged to remove the particles prior to nitrate analysis.
2.8 Q: Can I do nitrate
analysis on salt water samples using NECi NTK systems?
2.8 A: Yes, however, the standard curve
used for quantifying the results must be made using standards that also
contain salt water. This can be accomplished by obtaining nitrate-free
salt water like Instant Ocean which is available from us
or from many other suppliers. You could also prepare a sodium chloride
solution with a concentration about equal to that in salt water (0.2 M
NaCl) and use it to prepare the standards.
2.9 Q: Can soil samples
extracted in 2M KCl be used to analyze nitrate with NECi NTK systems?
2.9 A: Yes, however, the standard curve
must be prepared using the same high-salt extractant used to prepare the
samples.
2.10 Q: Can
physiological samples such as blood plasma or urine be analyzed with NECi
NTK systems?
2.10 A: Yes, in general, the
salt and protein content of these samples presents no significant
interference with nitrate analysis in NTK products.
2.11 Q: Can I
determine nitrate in units other than ppm nitrate-N using NECi NTK
Systems?
2.11 A: Yes, 1 ppm nitrate-N is
equal to 4.4 ppm nitrate or 71 µM nitrate. You can also determine nitrate
as a quantity since this is related to the volume of sample used in the
NTK System. In the Standard Range NTK series, 1 ppm nitrate-N is 3.55
nmole nitrate (0.05 ml sample * 71 µM nitrate). In the Low Range NTK
series, 1 ppm nitrate-N is 35.5 nmole nitrate (0.5 ml * 71 µM). In the
Standard Range NTK microplate kit, 1 ppm nitrate-N is 0.72 nmole nitrate
(0.01 ml * 71 µM). In the Low Range NTK microplate kit, 1 ppm nitrate-N is
3.55 nmole nitrate (0.05 ml * 71 µM).
|
