2.4 Quality assurance and quality control
Quality assurance and quality control is an efficient method to get a
more accurate result during the sampling and testing of groundwater. One
of the most important activities associated with sampling site selection
satisfies the objective of the present research. Once well selected,
sampling documentation and collection was carried out. All the samples
were collected in the 1 litre polyethylene bottle washed with a 10%
HNO3 solution. An ionic balance error (IBE) equation is
used to get an accuracy of analytical results between the concentration
of major cation and anion in milliequivalent per litre (meq/L) for all
collected samples (Eqn.2). The value of IBE should not exceed the
acceptable limit of ± 10%.
\(IBE=\frac{\sum{Cations-\ \sum\text{Anions}}}{\sum{Cations+\ \sum\text{Anions}}}\times 100\)