Instant Notes: Analytical Chemistry

Section A – The nature and scope of analytical chemistry A4 SAMPLING AND SAMPLE HANDLING The importance of obtaining a represent ...

measured, they may need to be physically separated before laboratory samples are taken. This is known as selective sampling. Typ ...

The distribution of toxic heavy metals or organic compounds in a land rede- velopment site presents a different problem. Here, t ...

Conversely, sample solutions containing organic solvents and other organic liquids should be stored in glass containers because ...

Table 1. Some methods for sample decomposition and dissolution Method of attack Type of sample Heated with concentrated mineral ...

Section A – The nature and scope of analytical chemistry A5 CALIBRATION AND STANDARDS Calibration With the exception of absolute ...

fashion to the other standards but omitting the analyte). The data is either plotted as a calibration graphor used to calculate ...

Bureau of Analytical Standards. CRMs or SRMs are produced in various forms and for different purposes and they may contain one o ...

Section A – The nature and scope of analytical chemistry A6 QUALITY IN ANALYTICAL LABORATORIES Quality control Analytical data m ...

● provision of full documentation and traceability of results to recognized reference materials through recorded identification; ...

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Section B – Assessment of data B1 ERRORS IN ANALYTICAL MEASUREMENTS The causes of measurement errors are numerous and their magn ...

The absolute error, EA, in a measurement or result, xM, is given by the equation EA=xM-xT where xTis the true or accepted value. ...

Determinate errors can be proportionalto the size of sample taken for analysis. If so, they will have the same effect on the mag ...

physical or physico-chemical measurement, but no one specific source can be identified. A series of measurements made under the ...

Errors are associated with every measurement made in an analytical procedure, and these will be aggregated in the final calculat ...

Section B – Assessment of data B2 ASSESSMENT OF ACCURACY AND PRECISION These two characteristics of numerical data are the most ...

It should be noted that good precision does not necessarily produce good accuracy (analyst A) and poor precision does not necess ...

between-runs variability. It may also be important to establish the precision of individual steps in an analysis. This is the mo ...

found within ± 1 sof the mean, approximately 95% will be found within ± 2 sand approximately 99.7% within ± 3 s. More practicall ...