Module 1

• Fundamental Research


  The first steps in unravelling the details of an unknown system frequently involve the identification of its constituents by qualitative chemical analysis
• Product Development


  The design and development of a new product will often depend upon establishing a link between its chemical composition and its physical properties or performance
• Product Quality Control


  Most manufacturing industries require a uniform product quality. To ensure that this requirement is met, both raw materials and finished products are subjected to extensive chemical analysis
• Monitoring and Control of Pollutants


  Residual heavy metals and organo-chlorine pesticides represent two well-known pollution problems. Sensitive and accurate analysis is required to enable the distribution and level of a pollutant in the environment to be assessed and routine chemical analysis is important in the control of industrial effluents
• Assay


  In commercial dealings with raw materials such as ores, the value of the ore is set by its metal content. Large amounts of material are often involved, so that taken overall small differences in concentration can be of considerable commercial significance. Accurate and reliable chemical analysis sis thus essential
• Medical and Clinical Studies


  The levels of various elements and compounds in body fluids are important indicators of physiological disorders
• Accuracy


  The closeness of an experimental measurement or result to the true or accepted value /target
• Analyte


  Constituent of the sample which is to be studied by quantitative measurements or identified qualitatively
• Assay


  A highly accurate determination, usually of a valuable constituent in a material of large bulk, e.g. minerals and ores. Also used in the assessment of the purity of a material, e. g. the physiologically active constituent of a pharmaceutical product
• Background


  That proportion of a measurement which arises from sources other than the analyte itself. Individual contributions from instrumental sources, added reagents and the matrix can, if desired, be evaluated separately
• Blank


  A measurement or observation in which the sample is replaced by a simulated matrix, the conditions otherwise being identical to those under which a sample would be analyzed. Thus, the blank can be used to correct for background effects and to take account of analyte other than that present in the sample which may be introduced during the analysis, e.g. from reagents
• Calibration

  A procedure which enables the response of an instrument to be related to the mass, volume or concentration of an analyte in a sample by first measuring the response from a sample of known composition or from a known amount of the analyte, i.e. a standard. Often, a series of standards, is used to prepare a calibration curve in which instrument response is plotted as a function of mass, volume or concentration of the analyte over a given range. If the plot is linear, a calibration factor (related to the slope of the curve) may be calculated. This facilitates the rapid computation of results without reference to the original curve. Process of configuring instruments to provide a result for a sample within an acceptable range
• Concentration


  The amount of a substance present in a given mass or volume of another substance
• Constituents


  • Major > 10%
  • Minor 0.01-10%
  • Trace 1-100 ppm (0.0001-0.01%)
  • Ultratrace < 1 ppm
• Detection Limit


  The smallest amount or concentration of an analyte that can be detected by a given procedure and with a given degree of confidence
• Determination


  A quantitative measure of an analyte with an accuracy of considerably better than 10% of the amount present
• Equivalent


  That amount of a substance which, in a specified chemical reaction, produces, reacts with or can be indirectly equated with one mole (6.023 × 10^23) of hydrogen ions. This confusing term is obsolete but its use is still to be found in some analytical laboratories
• Estimation


  A semi-quantitative measure of the amount of an analyte present in a sample, i.e. an approximate measurement having an accuracy no better than about 10% of the amount present
• Interference


  An effect which alters or obscures the behavior of an analyte in an analytical procedure. It may arise from the sample itself, from contaminants or reagents introduced during the procedure or from the instrumentation used for the measurements
• Internal Standard


  A compound or element added to all calibration standards and samples in a constant known amount
• Masking


  Treatment of a sample with a reagent to prevent interference with the response of the analyte by other constituents of the sample
• Matrix


  The remainder of the sample of which the analyte forms a part. Includes all other than analyte
• Method


  The overall description of the instructions for a particular analysis
• Precision


  The random or indeterminate error associated with a measurement or result. Sometimes called the variability, it can be represented statistically by the standard deviation or relative standard deviation (coefficient of variation). Reproducibility is the other term
• Primary Standard


  A substance whose purity and stability are particularly well established and with which other standards may be compared
• Procedure


  A description of the practical steps involved in an analysis
• Reagent


  A chemical used to produce a specified reaction in relation to an analytical procedure
• Sample


  A substance or portion of a substance about which analytical information is required, e.g blood, urine
• Sensitivity


  The change in the response from an analyte relative to a small variation in the amount vine being determined. The sensitivity is equal to the slope of the calibration curve, being constant if the curve is linear. The ability of a method to facilitate the detection or determination of an analyte
• Standard


  The pure analyte or a substance containing an accurately known amount of it which is used to calibrate an instrument or to standardize a reagent solution
• Standard Addition


  A method of quantitative analysis whereby the response from an analyte is measured before and after adding a known amount of that analyte to the sample
• Standardization


  Determination of the concentration of an analyte or reagent solution from its reaction with a standard or primary standard
• Technique


  The principle upon which a group of methods is based
• Validation of Methods


  In order to ensure that results yielded by a method are as accurate as possible, it is essential to validate the method by analyzing standards which have an accepted analyte content, and a matrix similar to that of the sample. The accepted values for these validated standards are obtained by extensive analysis, using a range of different methods. Internationally accepted standards are available
• Analytical Problem and their Solution

  1. Define first the Problem

  2. Choice of Method

  3. Sampling

  4. Preliminary Sample Treatment

  5. Separations

  6. Final Measurement

  7. Method Validation
• Matrix


  Collection of all of the components in the sample containing an analyte
• Specific


  Techniques or reactions that work for only one analyte
• Selective


  Techniques or reactions that apply to only a few analytes
• Calibration


  Process of determining the proportionality between analyte concentration and a measured quantity
• Assessment of Results


  Results obtained from an analysis must be assessed by the appropriate statistical methods and their meaning considered in the light of the original problem