External quality assessment of absorbance measurements on spectral and spectral-line photometers.
From 1984-1987, 12 quality control surveys on photometric measurements were carried out in 600-800 laboratories. The participants measured the photometric absorbance of the control samples at 4 wavelengths of the mercury spectrum: 334.1 nm, 365.4 nm, 404.7 nm and 546.1 nm. The medians of the results were without exception lower than the target values, but only very few of them deviated more than 1%. The dispersion of the values did not follow a normal distribution. Two thirds of the values were concentrated within a very small range, while about 10% lay outside the 2- to 3-fold range. It was found that longer wavelengths resulted in a smaller dispersion of readings than shorter ones. Furthermore, precision showed a significant dependency on the absorbance readings of the samples, on the one hand, and on the different photometers, on the other.
Institut für Klinische Biochemie, Universität Bonn.
G
G
Röhle
H
H
Schlebusch
R
R
Kruse
W J
WJ
Geilenkeuser
D002624:Chemistry, Clinical / Q000592:standards*; D007753:Laboratories / Q000592:standards*; D010783:Photometry / Q000295:instrumentation* / Q000592:standards; D011786:Quality Control; D013053:Spectrophotometry / Q000295:instrumentation* / Q000592:standards