Question

a. What type of error is responsible for high precise but low accurate results? b. How can you avoid or reduce this error?

Answer 1

1. systematic error.

2.

There are three types of systematic errors:

•      Instrumental errors (caused by non-ideal instrument behaviour by faulty calibrations or by use under inappropriate conditions & Calibration eliminates most instrumental errors)

•      Method errors (caused by non-ideal chemical/physical behaviour of reagents & reactions

•      Personal errors (caused by the carelessness or personal limitations of the experimenter)

Elimination of systematic errors

•      Continuous calibration of equipment

•     Personal errors can be reduced by careful and disciplined laboratory work.

•      Systematic checking of instrument readings, notebook entries and calculations.

•      Careful selection of the analytical method or an automated procedure can eliminate errors due to limitations of the experimenter.

•      Independent analysis is helpful to eliminate systematic errors

If standard samples are not available, practice a second independent and reliable analytical method in parallel to minimize the possibility of some common factor in the sample.

•      Blank determinations is helpful to eliminate systematic errors

Blank contains all the reagents and solvents used in a determination except the analyte.  In a blank determination, all steps of the analysis are performed and the results are applied as a correction factor to the sample measurements to understand errors due to interfering contaminants from the reagents and vessels employed in the analysis