some analytical terms

The first important distinction we will make is among the terms  “analysis,” “determination,” and “measurement.” 

An analysis provides chemical or physical information about a sample. 

The components of interest in the sample are called analytes, and the remainder of the sample is the matrix. 

In an analysis we determine the identity, concentration, or properties of the analytes. To make this determination we measure one or more of the analyte’s chemical or physical properties.

analysis

A process that provides chemical or physical information about the constituents in the sample or the sample

itself.

analytes

The constituents of interest in a sample.

matrix 

All other constituents in a sample except for the analytes.

determination

An analysis of a sample to find the identity, concentration, or properties of the analyte.

measurement

An experimental determination of an analyte’s chemical or physical properties.

The second important to distinguish among four levels of analytical methodology: techniques, methods, procedures, and protocols.

A technique is any chemical or physical principle that can be used to study an analyte. Many techniques have been used to determine analyte .

A method is the application of a technique for the determination of a specific analyte in a specific matrix.

A procedure is a set of written directions detailing how to apply a method to a particular sample, including information on proper sampling, handling of interferents, and validating results. A method does not necessarily lead to a single procedure, as different analysts or agencies will adapt the method to their specific needs.

a protocol is a set of stringent written guidelines detailing the procedure that must be followed if the agency specifying the protocol is to accept the results of the analysis. Protocols are commonly encountered when analytical chemistry is used to support or define public policy. 

technique

A chemical or physical principle that can be used to analyze a sample.

method

A means for analyzing a sample for a specific analyte in a specific matrix.

procedure

Written directions outlining how to analyze a sample.

protocol

A set of written guidelines for analyzing asample specified by an agency.