How to minimize Analytical Measurement Errors?

How to minimize Analytical Measurement Errors?
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Diligence in laboratory reduces errors

Analytical measurements may appear to be simple but present a significant potential for errors because they involve several stages from sample collection to sample processing and final observation. If proper care is not taken at any stage there is ample scope for errors to creep in.

Errors in any analytical measurement are a sum total of :

  • Errors in procedure
  • Measurement errors
  • Errors in noting down results or transcription
  • Calculation errors

The objective of this article is to suggest guidelines for minimization of measurement errors

Determinate and Indeterminate errors

Determinate Errors

Systematic errors can be identified even before the start of analysis and can be minimized through corrective actions. These errors comprise of errors in the method, instrumental errors and reagent errors. Such errors can be corrected through

  • Calibration of instrument against reference standards
  • Control of laboratory environment
  • Increasing the number of observations
  • Use of high quality reagents and standards procured from reliable sources and method validation
  • Running blanks and standards in between runs
  • Making observations at higher concentration levels or increasing sensitivity through use of derivatizing agents

Personal Errors

Personals errors are not related to the technique but are due to a personal bias in making observations or lack of attention to the procedural details

  • Errors in weighing or use of uncalibrated balances or weights
  • Incomplete drying of sample or precipitate before weighing
  • Material loss during transfer of precipitates or sample processing
  • Errors in quantitative transfer of solutions
  • Parallax errors while making volumetric observations
  • Errors in serial dilutions
  • Errors in colour change observation during titrimetric determinations

Personal errors cannot be eliminated totally but can be reduced through proper training and introduction of automated analysis systems.

Errors in noting down results or transcription errors and calculations are greatly taken care of by modern software controlled techniques where the manual data recording and calculations are taken over by the software and procedural errors can be eliminated by validation of methods prior to adoption.

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