1.0 OBJECTIVE:
To lay down a standard procedure for analysis of purified water.
- scope:
This SOP is applicable for analysis of purified water in Quality Control
- RESPONSIBILITY:
Officers / Executive – Quality Control shall be responsible for follow that procedure.
- ACCOUNTABILITY:
Manager- Quality Control and Head QA shall be accountable for compliance of this SOP.
- ATTACHMENTS:
Nil
- PROCEDURE:
Collect the sample as per standard operating procedure for water sampling and analysis for chemical and microbiological parameters as per their specifications.
6.1 Chemical Analysis:
6.1.1 Description
Examine the water physically such as color, odor.
6.1.2 Hardness
Take 100 ml sample add 2 ml of ammonia buffer pH 10.0, 50 mg of mordant black 11 mixture and add of 0.01 M disodium edetate until, a pure blue color is produced. Measures the volume of disodium edetate used and calculate the hardness by the following formula.
Hardness as mg/L = ml of EDTA used x 1000 mg/L
Sample volume
6.1.3 Total dissolved solids (TDS)
Measure the conductivity at 25 °C with a calibrated conductivity meter and convert the value in TDS by the following formula.
TDS in mg/L= conductivity in mS X 0.667 (Geographical factor of area)
6.1.4 Acidity
Take 10 ml sample freshly boiled and cooled sample, add 0.05 ml of methyl red solution and mix, the resulting solution is not red.
Interpretation of result: If the solution is in red color the sample is Acidic
6.1.5 Alkalinity
Take 10 ml sample freshly boiled and cooled sample, add 0.1 ml of bromothymol blue solution and mix.
Interpretation of result: If the solution is in blue color the sample is Alkaline.
6.1.6 Ammonium
Take 20 ml sample add 1 ml of alkaline potassium mercuri-iodide solution and allow standing for 5 minutes. When vertically viewed the solution is not more intensely colored than a solution prepared at the same time by adding 1 ml of alkaline potassium mercuri-iodide solution to a solution containing 2.5 ml of dilute ammonium chloride solution and 7.5 ml of the liquid being examined. Take 100 ml sample add 2 ml of ammonia buffer pH 10.0, 50 mg of mordant black 11 mixture and 0.5 ml of 0.01 M disodium edetate, a pure blue color is produced
6.1.7 Heavy Metals
In a glass-evaporating dish evaporate 150 ml of sample to 15 ml on a water bath.
Standard solution
Into a small Nessler Cylinder, pipette 10.0 ml of lead standard solution (1ppm Pb).
Test Solution
Pipette 12 ml into a small nessler cylinder.
Procedure
To the cylinder containing the standard solution add 2.0 ml of the test solution and mix. To each cylinder add 2 ml of acetate buffer pH 3.5, mix, add 1.2 ml of thioacetamide reagent, allow to stand for 2 minutes and view downwards over a white surface, the colour produced with the test solution is not more intense than that produced with the standard solution.
6.1.8 Chloride
Take 10 ml sample add 1 ml of 2 M nitric acid and 0.2 ml of 0.1 M silver nitrate, the appearance of the solution does not change for at least 15 minutes.
6.1.9 Nitrate
Take 5 ml sample in a test tube immersed in ice add 0.4 ml of a 10% w/v solution of Potassium chloride, 0.1 ml of diphenylamine solution and dropwise with shaking 5 ml of sulphuric acid. Transfer the tube to a water bath at 50°C to allow standing for 15 minutes. Any blue colour in the solution is not more intense than that in a solution prepared at the same time and in the same manner using a mixture of 5.5 ml of nitrate free water and 0.5 ml of nitrate standard solution (2 ppm NO3).
6.1.10 Sulphate
Take 10 ml sample add 0.1 ml of 2 M Hydrochloric acid and 0.1 ml of barium chloride solution. The appearance of the solution does not change for at least 1 hour.
6.1.11 Oxidisable substances
Take 100 ml sample add 10 ml of 1 M sulphuric acid and 0.1 ml of 0.02 M potassium permanganate and boil for 5 minutes, the solution should remain faintly pink.
6.1.12 Residue on evaporation
Evaporate 100 ml sample to dryness into hot plate and dry to a constant weight at 105°C. The residue weighs not more than 1 mg (0.001%).
Residue on evaporation: W2-W1 × 100 (mg/L)
ml of solution taken
W1 : Weight of Evaporating dish
W2 : Weight of Evaporating dish + Residue
6.1.13 Total Organic Carbon
Analyse the sample for TOC in a calibrated TOC Analyser as per SOP.
Alert and Action limit for Total Organic Carbon of water system
Purified water: Alert Limit (ppb) 300 & Action Limit (ppb) 500
6.1.14 Conductivity
Take the 100 ml sample in a suitable container, and stir the test sample by maintaining the temperature 25°C ± 1°C, measure the conductivity with the help of calibrated conductivity meter.
Temperature and the respective Conductivity
| Temperature (°C) | Conductivity μS cm‾ 1
|
| 0 | 0.6 |
| 5 | 0.8 |
| 10 | 0.9 |
| 15 | 1.0 |
| 20 | 1.1 |
| 25 | 1.3 |
| 30 | 1.4 |
| 35 | 1.5 |
| 40 | 1.7 |
| 45 | 1.8 |
| 50 | 1.9 |
| 55 | 2.1 |
| 60 | 2.4 |
| 65 | 2.4 |
| 70 | 2.5 |
| 75 | 2.7 |
| 80 | 2.7 |
| 85 | 2.7 |
| 90 | 2.7 |
| 95 | 2.9 |
| 100 | 3.1 |
6.1.15 pH
Take 100 ml of sample and then measure the pH with the help of Calibrated pH meter.
Limit: 5.00 To 7.00
- REFERENCES:
In-house
- ABBREVIATIONS:
SOP: Standard Operating Procedure
QC: Quality Control
QA: Quality Assurance
Ppb: Parts per billion
M: Molarity
°C: Degree centigrade
mg: Miligram
TDS: Total dissolved solids
ppm: Parts per million
- DISTRIBUTION LIST:
Quality Assurance Department
Quality Control Department
- HISTORY OF REVISION:
| Version Number | Effective Date | Reason for Revision |
