Nitrites Lab Report

INTRODUCTION Nitrites are composed of nitrogen and oxygen together with nitrite ions found in salts that have chemical formula NO2ˉ. Nitrites are part of the nitrogen cycle that is the transformations of nitrogen and nitrogen containing compound in nature. Nitrites alone will not contribute to pollution problem but when nitrites combine with ammonia, it may contribute environmental contamination. Nitrites can enter the water through the breakdown of human or animal sewage by bacteria in the environment or by runoff from fertilized land. Nitrites are extensively used in the process to cure meats. However, nitrites produce a serious illness that is brown blood disease in fish even though they do not exist un the environment for

100ml of each standard solution are prepared and transfer to calibration flash by using different concentration which as 0.05mg/l, 0.10mg/l, 0.30mg/l, 0.50mg/l, 1.00mg/l and blank.

A pipette is used to transfer 5ml of each different concentration of standard solution into each three replicates of test tubes.

6. 1ml of pipette is used to transfer 0.1 ml of sulfanilamide solution into the test tubes and shaken gently.

7. The reagent allowed to react in 2-10 minute to complete the reaction.

8. 0.1 ml of naphthyl-ethylene diamine reagent is added and immediately mixed.

9. Step 6-8 is repeated for sample B and standard solution with 0.05mm/l, 0.1mm/l, 0.3mm/l, 0.5mm/l and 1.0mm/l. Each three replicate is made.

10. The absorbance of sample measured with spectrophotometer at 543nm after one hour.

11. All the result is tabulated in the table.

12. Graph of absorbance against concentration is plotted and the concentration of nitrite sample A and B determined by standard curve and F factor approached.

RESULT AND CALCULATION Concentration Replicate Average Abs

(mg/l) 1 2

Nitrogen comes from decomposing organic materials like manure, plants, and human wastes. Often the nitrogen (N) comes from ammonia (NH3) or ammonium (NH4). It is the primary source of nitrogen for plants, and it occurs naturally in soil and water. But if the levels of nitrate get too high, it can pose a potential health risk. Sources of excess nitrate in water include fertilizers, septic systems, waste water treatment effluent, animal wastes, industrial wastes, and food processing wastes. There have two ways to determine the calculation which is by using the standard curve: absorbance against concentration graph and formula of concentration. From the standard curve, there is one equation which is y=1.0685× to calculate the concentration of nitrate. Another way is applying the formula that is concentration (mg/ l) = sample absorbance x F factor. The F factor is calculated by using 1.0 mg/l / (Es-Eb). From two ways to determine the calculation, the equation from the standard curve is more accurate than the formula of concentration. This is because all the reading is recorded step by step and the standard curve have done after experiment. While, the formula of concentration is applied by theory which is choose the reading of concentration that nearer the reading of water sample. So, F factor will influenced the