PENENTUAN PRESISI DAN BIAS METODE PENGUJIAN AIR DAN AIR LIMBAH MELALUI UJI BANDING ANTAR LABORATORIUM

Abstract

Determination of method precision and bias for testing of water and wastewater can be conducted by inter-laboratory
comparison. Performance evaluation sample was determined by provider as assign value and distributed to
participants. The assign value is used as comparison with laboratory result and grand mean is calculated to determine
method bias. The method precision is determined by standard deviation from result of all laboratories participant
divided by grand mean. The result of inter-laboratory comparison for testing of SO4
2- showed that method
precision 5.4% and method bias 0.3% for assign value 19.9 mg/l. On the other hand, the standard methods for the
Examination of water and wastewater showed that the method precision and bias for SO4
2- are 1.7% and 9% for assign
value 7.45 mg/l. For testing of Cl- in water and wastewater, the result of inter-laboratory comparison gave method
precision and bias 7.4% and 2.1% for assign value 29.5 mg/l. The method precision and bias from the Standard
Methods are 4.2% and 1.7% with assign value 241 Cl-/l. Furthermore, the method precision from the standard
methods for COD is 5.6% with assign value 195 mg/l and method precision from the result of inter-laboratory
comparison is 6.4%, method bias 3.4% with assign value 194 mg/l. The participant of inter-laboratory comparison
program could comply with the standard methods for testing of SO42-, Cl-, COD in water and waste water.