Annexes
3. Préparation des réactifs pour l’analyse des sels nutritifs
3.1. Nitrate/Nitrite
REAGENTS
A. Buffer solution (1 liter)
Required chemicals: Imidazol....... 17.5 g.
C3N4N2
Hydrochloric acid ........... x ml.
HCl (1M)
Distilled water
H2O
Preparation: Dissolve the imidazol in ± 800
ml distilled water. Adjust the pH to 8.2 ± 0.1
with the hydrochloric acid solution. Add the
Brij 35 and mix. Fill up to 1 liter with distilled
water and mix.
Note: Solution is stable for 1 week. Store at
4°C when the solution is not used.
Brij 35 (30%)................... 1 ml.
B. Colour reagent (1 liter)
Required chemicals: o‐Phosphoric acid ....
150 ml.
H3PO4 (85%)
Sulfanilamide ................. 10 g.
C6H8N2O2S
N‐(1‐Naphthyl)ethylene
diamine
dihydrochloride ............ 0.5 g.
C12H16Cl2N2
Distilled water H2O
Preparation: Dilute the o‐phosphoric acid in ±
700 ml distilled water. Add the sulfanilamide
andthe N‐(1‐naphthtyl)ethylene diamine
dihydrochloride and dissolve. Fill up to 1 liter
with distilled water and mix.
Note: Solution is stable for 2 weeks. Store in a
dark coloured bottle.
C. Rinsing liquid sampler
Required chemicals: Distilled water
H2O
STANDARDS
Stock solution 100 mg N/liter (1 liter)
Required chemicals: Sodium nitrate .......
606.8 mg.
NaNO3
Distilled water
H2O
Note: For sea water samples, adjust the salinity
of the rinsing water sampler to the same level
as the salinity of the sea water
samples when matrix peaks reach the
same level as the detection limit. Use ultra
pure sodium chloride or “zero” seawater
for adjustment.
Solution is stable for 1 week.
Preparation: Dissolve the sodium nitrate in ±
800 ml distilled water. Fill up to 1 liter with
distilled water and mix.
Note: Solution is stable for 4 weeks. Store at
4°C when the solution is not used.