PT Scheme for Pre-university Students

Abstract

As part of the Valid Analytical Measurement (VAM) programme and in conjunction with Nuffield Science, an organisation involved with vocational and academic qualifications, LGC has developed a proficiency testing (PT) scheme appropriate for pre-university students.

All PT schemes share two key objectives:

• the provision of a regular, objective and independent assessment of the accuracy of analytical laboratory’s results on routine test samples

  the promotion of improvements in the quality (accuracy) of routine analytical data.

In broad terms these are the objectives of the PT scheme organised by LGC for schools and colleges. The students, working in groups, have to determine the concentration of ethanoic acid samples using good laboratory practice. The PT scheme is conducted in a similar manner to PT schemes used by professional analytical chemists and as such

• vialed samples of ethanoic acid are distributed to all participating centres

  the homogeneity and stability of the acid solutions are measured by analysts at LGC

  statistical analysis is performed on the students experimental data and their calculations of the acid concentrations.

In this way, the performance of students in one centre is compared with that of students at the other centres and this information is relayed back to the participating centres.

The PT scheme has been run on two occasions and from teacher’s feedback, the PT scheme is a ‘user friendly’ activity for both students and teachers. Participating centres also receive teachers notes, student information sheets (practical details) and student reporting sheets. In the light of teachers comments, the difficulties encountered by students performing the analysis and the student reports a ‘Guide to Improving Analytical Quality in Chemistry’ has been produced to help students with analytical techniques such as titration.

The PT scheme for schools and colleges runs over an entire school term (approximately 3 months) and so this allows students to perform the analysis when it best fits in with their studies. It provides a friendly analytical challenge for students and, at the same time, it has helped to improve the way in which students perform their measurements.