Hello i want a method to determine nitrate in water samples without a device otherthan spectrophoto meter???
Three different methods for nitrate determination in environmental samples were comparatively examined.
1. From the data obtained it is concluded that the cadmium reduction method is the most suitable for every type of environmental water samples.
2. on the contrary, the electrode screening method suffers from many interferences and is not suitable for any type of sample.
3. The direct spectrophotometric method has been found to be applicable mostly for fresh water samples
Nitrate Testing Procedure 1. Fill the sample bottle with sample water. Use gloves if drawing the sample by hand. 2. Rinse and fill one test tube to the 2.5 mL line with water from the sample bottle. 3. Dilute to the 5 mL line with the Mixed Acid Reagent. Cap and mix. Wait 2 minutes. 4. Use the 0.1 g spoon to add one level measure (avoid any 50-60 times in one minute). Wait 10 minutes. 5. Insert the test tube into the Nitrate Nitrogen Comparator. Match the sample color to a color standard. Record the result as mg/L(ppm) Nitrate Nitrogen (NO3-N). To convert to mg/Nitrate (NO3) multiply by 4.4. 6. Place the reacted sample in a clearly marked container. Arrangements should be made with toxic material handlers for safe disposal. Please wash your hands after this water test is completed..
I have found that tests that use the cadmium reduction method in a cuvette (test tube) ---- rather than with, say, a flow analyzer ---- just aren't very reliable. I suspect it's just too difficult to get complete reduction by shaking the sample in a cuvette.
I've been curious about the ion specific electrodes, but I don't have experience with them.
There are many brands of chemical to make fast nitrate determination with a spectrofotometer, even the brand of the equipment could sugest you a particular method for it. Just an example you can get Hash nitrate test (see the file).
The nitrate ion (NO3-) in the water sample was determined using a UV spectrophotometric method at 220 and 275 nm wavelengths.
Reagents: Nitrate-free water: Double distilled water was used to prepare all solutions and dilutions.
Stock nitrate solution: Potassium nitrate (KNO3) was dried in an oven at 105ºC for 24 hours. 0.7218 g KNO3 was weighed out and it was transferred to a 1000 mL volumetric flask, and made up to the mark with distilled water gradually, where 1 mL = 100 μg NO3-N.
Intermediate nitrate solution: 100 mL stock nitrate solution was taken in a 1000mL volumetric flask, and distilled water was added gradually and finally made up to the mark where 1 mL = 10 μg NO3-N. 2 mL CHCl3was used per litter solution to preserve it for at least 6 months.
1N Hydrochloric acid (HCl) solution: 83 mL of concentrated HCl was measured and transferred to in a
1000mL volumetric flask and finally made up to the mark 1000 mL by distilled water gradually.
Procedure: Treatment of sample: 1 mL of 1 N HCl solution was mixed thoroughly in a 50 mL clear sample
and filtered.
Preparation of standard curve: The proportions of 0.50, 1.0, and 2.0 mL intermediate nitrate solutions were taken in three different 1000mL volumetric flasks, and distilled water was gradually added and thoroughly shaken, and finally made up to the mark by distilled water. The absorbance of the water samples was determined by a UV Spectrophotometer. A standard curve was made by plotting the absorbance against the concentration (Figure-2.1 in Appendix-2).
Spectrophotometric measurement: The absorbance was read against distilled water set zero absorbance.
A wavelength of 220 nm was used to obtain a NO3- reading and a wavelength of 275 nm was used to
determine interference due to dissolved organic matter.
Calculation: The estimation of NO3-N was measured using a UV-Spectrophotometer at two wavelengths
i.e., 275 and 220. The absorbance for samples and standard solutions was taken at two wavelengths and the
absorbance reading at 275nm was subtracted from the reading at 220nm for each sample and standard
solution.
Nitrate-Nitrogen (NO3-N mg/L) =
Nitrate (NO3- mg/L) = [NO3] × 4.429
Attached are two files for the determination of nitrates in water by titration and volumetric analysis,
Goodluck
Uros Stojakovic , The standard Kjeldahl method specifically does not include nitrate in its results. For practical purposes in a laboratory, "total nitrogen" is often defined as Kjeldahl nitrogen plus nitrate nitrogen. Here, Kjeldahl includes ammonia and digestible organic forms, and nitrate includes nitrate and nitrite.
I suggest ignoring the electrode methods and the probes are unstable, have a short operating life, and costly.
The cadmium based system requires great consistency of the sample preparation to develop reasonable precision and accuracy.
Sometimes aquarium test strips are close enough.
I would love to have a Raman system for Nitrate and Nitrite, but for now need to use the Spectraphotometer methods.
photometer method with vials, try MD600 or multidirect Lovibond,you will have result for about 10min
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