What to consider in Selection of Method for Required Analysis

Sample tested with Complexometric reactions principle(ligands are 1 10-phenanthroline and EDTA from left to right respectively.)

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Every material natural or man-made can be analyzed by taking help of the versatile analysis tools available today. Modern techniques have capabilities to provide you the analysis in the most complex

matrices and at the required concentration levels.

As a chemist you should apply your theoretical concepts and skills acquired over the years to arrive at the probable options but the guidelines provided in the article will be helpful to you for selection of the appropriate method. You should consider yourself lucky if already a method is available in the laboratory and it is documented in the laboratory standard test procedures. However, every time luck may not be favourable so you are recommended to proceed as suggested below:

Step – I – Have clarity on your sample and analysis requirements

Before you undertake any analysis you should ask yourself some basic questions and be ready with answers before adopting a method.

• Source of sample and if any special precautions are required for its handling
• Compounds or elements that need to be identified or quantified
• Knowledge of sample matrix and other analytes present so as to determine interferences, if any
• Concentration levels at which the results are required
• Required degree of accuracy and precision

Step – II – Starting your search

• Look for the methods suggested in standard textbooks.
• Search for methods and standard references such as Pharmacopoeia’s, CODEX, ASTM, EPA, APHA, etc depending on nature of your sample
• Pubmed.com for methods published in indexed journals
• Google scholar for a broader range of journals and books
• Google.com should be your last option as it will provide you a large number of choices which will confuse you even further.

Stage – III – Practical viability of the selected method

• Methods should not be too lengthy or involve numerous stages such as concentration, extractions, serial dilutions, derivatizations, etc as such stages are capable of introducing errors.In addition lengthy procedures are time-consuming and lower the laboratory throughput
• Availability of required equipments and reagents
• Method should be for a same or a closely matching matrix
• The selected method should provide a high degree of reproducibility and provide a wide linear dynamic range, i.e, it should be possible to determine both low and high concentration levels
• The method should be both time and cost effective

Stage – IV– Key considerations before method adoption

• The method should be validated to ensure that it meets its intended purpose.
• Personal are provided training on technique, safe handling of equipment and chemicals and correct interpretation of results
• Calibration procedures are well understood
• Required reagents and chemicals are available of high quality and from reliable sources

It is understood that your search will not end up with an ideal method which meets all the criteria but do keep in mind that the simplest method will not necessarily be the most appropriate choice. Validation of the selected method is of utmost importance before it is put into practice.
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