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					Nitrates samples were analyzed on a Lachat Quik-Chem 8000, following Quik-Chem
Method 31-107-04-1-C.

2000. Diamond, David H. Determination of nitrate and/or nitrite in brackish or seawater
by flow injection analysis colorimetry. Quik-Chem Method 31-107-04-1-C. Zellweger
Ananlytics, Lachat Instrument Division, 6645 West Mill Road, Milwaukee, WI 53218.

Summary: Samples are passed through a copperized cadmium column to reduce nitrate
to nitrite. The nitrite (both original and reduced nitrate) is determined by diazotizing with
sulfanilamide and coupling with N-(1-napthyl)-ethylenediamine dihydrochoride to form a
highly colored azo dye which is measured colorimetrically.

Working Range: 5-50μm, MDL 0.12μm

Standard Preparation:
50mM stock standard-in a 1 liter volumetric flask dissolve 0.5055g dried (1hour at 60C) potassium nitrate (KNO3) into about 800ml
distilled water. Dilute to 1 liter with DI water and invert several times to mix. Can be stored refrigerated for up to 3 months.


50μm Working Stock Standard-In 1 L volumetric dilute 10ml 50mM stock to mark with
DI water, invert to mix.

Working Standards (Prepare Daily):
50μm-dilute 250ml 50μm working stock std. with 0ml DI water
25μm-dilute 125ml 50μm working stock std. with 125ml DI water
10μm-dilute 50ml 50μm working stock std. with 200ml DI water
5μm-dilute 25ml 50μm working stock std. with 225ml DI water
0μm-250ml DI water

				
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posted:11/30/2011
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