For details on handling water chemistry samples, see Chapter 8.2 . 7.8.2.2 Laboratory analyses The transport and storage period should be kept to a minimum. The set of parameters to determine are given in Table 7.8.1 . Total N has now been added, and enables organic N to be calculated. Because the porous cup itself acts as a filter, filtering of the sample for analysis is probably unnecessary.
Further testing is advised before using expensive membrane filters.
However, filtering for some analytical procedures may be necessary, e.g. with ion chromatography to preserve the exchange columns for longer. It is also important to note the limits of some techniques, e.g. the detection limits for metals determined by ICP, at least emission spectrometer models, are relatively high. Each NFP is expected to ensure that good laboratory practice is followed and are responsible for the quality of data reported to ICP IM Programme Centre. For methods on checking data, QC and precision and accuracy, see American Public Health Association. The results of quality controls, laboratory intercalibrations etc.