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Method for the determination of aldehyde residues on flexible endoscopes

Bepalingsmethode voor aldehyde-residuen in flexibele endoscopen


The Dutch National Institute for Public Health and the Environment has developed a method for the extraction of formaldehyde and glutaraldehyde residues on flexible endoscopes and for the analysis of these extraction samples. This method was used on 38 gastroscopes in 13 hospitals to gain an insight into the amount of aldehyde residues on endoscopes used in daily routine. The extraction of the distal end of endoscopes was performed at 40 degrees C in a jacketed glass tube using water as the extraction fluid. The aldehydes combined with the reagent DNPH, allowing these compounds to be separated and detected using HPLC techniques. The method is sensitive enough to detect and quantify residues of formaldehyde and glutaraldehyde present at the distal end of flexible endoscopes. The maximum amounts of formaldehyde and glutaraldehyde on a gastroscope during this investigation came to 11.0 plus or minus 4.4 ug and 68.0 plus or minus 27.2 ug, respectively. There were significant differences between the amount of residual formaldehyde and glutaraldehyde on the endoscopes, depending on the hospital it came from. Moreover, there was a significant difference between the amount of residual formaldehyde on endoscopes that had been disinfected using different disinfectants. This method can be used for process development of endoscope washer-disinfectors, when there is doubt about the condition of an endoscope and to compare the levels of residual aldehydes when using different disinfectants.

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