An Overview of Basic Principles of Analytical Methods - Field Sampling: Principles and Practices in Environmental Analysis - page 246

10
An Overview of Basic Principles of Analytical
Methods
Rolf Meinholtz
The planning for an analytical strategy begins with the original question asked by the
client and runs through sampling of the field in question, subsequent characterization of
the sample, sample analysis, and data reduction to create the final report. During this
process it is necessary to ask some essential questions at a fundamental level. The first is,
What is the original question that is being asked by the client? Two basic factors must be
considered here. The first is the amount and nature of the sample; that is, is it solid,
liquid, or gas? The second is the potential concentration levels of components in the
sample. Once these questions are considered and an analytical strategy is developed, it is
time to take a sample. The entire process from initial question to final report is seen in the
flow chart in Figure 10.1.
Once the sample has been taken some of it is enclosed in containers and sent to the
commercial analytical laboratory for analysis. The rest is used to perform what are
termed field parameters, field tests, or field analyses. Field analyses are those that—
because the analytes change rapidly—must be measured immediately and directly [e.g.,
dissolved oxygen (DO)]. (See Tables 10.1 and 10.2 for examples of analyses done in the
field, those done in the commercial laboratory, and hold times.) These are general lists,
and in some cases additional field analyses may be dictated by the client or the analytical
laboratory, depending on the analytical