Water Analysis PDF

WATER ANALYSIS pH Measurement Universal indicator paper. pH meter (this is more accurate) Atomic Absorption Spectrometry; Principles Atoms in the ground state absorb light of a particular wavelength characteristi c of the element. Absorbance is directly proportional to concentratio nentration. Proce...

WATER ANALYSIS pH Measurement Universal indicator paper. pH meter (this is more accurate) Atomic Absorption Spectrometry; Principles Atoms in the ground state absorb light of a particular wavelength characteristi c of the element. Absorbance is directly proportional to concentratio nentration. Processes Sample solution is sprayed into a flame, and the sample element is converted into atoms of the element. Groundstate atoms absorb radiation from a source made from the element. Absorbance is measured. Colorimetry When testing a sample of swimming pool water, a DPD no. 1 tablet must be added to the water sample. Free chlorine oxidises DPD to form a red product. The red colour can be compared to a standard to find the concentration. Anion Testing Anion test for 1. Nitrate brown ring test 2. Phosphate Addition of ammonium molybdate produces a yellow precipitate → → Suspended solids Suspended solids cause turbidity in water (ie. A cloudiness or lack of clarity). Can be estimated by filtration. Dissolved Solids The concentration of these solids can be estimated by evaporation. Total Hardness EDTA titration Biochemical Oxygen Demand (BOD) The biochemical oxygen demand (BOD) of a water sample is defined as the amount of dissolved oxygen in ppm consumed by biological action, when the sample is kept at 20°C, in the dark, over a period of 5 days. Dissolved O₂ found by Winkler Titration