Sample (Water) | Concentration of Fluoride(mg/L) by direct Measurement | Concentration of Fluoride (mg/L) by standard addition method |
W1 | 0.39 | 0.37 |
W2 | 0.28 | 0.26 |
W3 | 0.18 | 0.17 |
W4 | 0.16 | 0.14 |