[Bartlett's test in the statistical determination of amino acids using an automatic analyzer]

Bartlett's test was applied to estimate the precision of the determination method of amino acids using the automatic analyser "Unichrom". The calculations were done on the basis of the results obtained from determinations of the amino acids in 8 different materials of plant and animal origin. No significant differences among standard deviation of 11 amino acids were found; this allowed the authors to express the precision of the method for these amino acids by mean standard deviation. In order to express the error of the method in relative values (variation coefficient), the analysis of variance was carried out, which showed a significance of differences in the mean levels for all amino acids. Confidence intervals of the mean levels of the amino acids determined by the Duncan test allowed us to form groups of materials in which the levels of the individual amino acids were similar. The variation coeffitients (the error of the method expressed in percentage) were calculated for the material groups which did not differ significantly in regard to the mean content of the given amino acid. In the majority of cases the error of the method for determining amino acids was about 5%. As a rule, it was higher only for threonine and tyrosine, and it was from 5 to 9% in the particular materials.