The management of the analysis environment, the selection of bottles, the quality of rinse water, and the performance of the analysis apparatus become important for evaluating the quality of ultrapure water. For example, only after measuring the bottle blank beforehand and confirming that there is no pollution of the bottle, the bottle is used for sampling.
The analysis apparatus uses an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). Because elements are ionized by the high temperature plasma of argon gas (7000 °C or more), and each mass is measured by the mass spectrometer, the ICP-MS can measure very small levels of pollution.
Ultrapure water is easily polluted since impurities occur in ultra small quantities in ultrapure water. Pollution is difficult to avoid when a method that concentrates the sample is used. Table 1 shows the detection limit of each element under standardized analysis conditions without sample concentration.
Table1 Relation between element and detection limit (Unit: ng/l)
