BUCHI Extraction Unit E-816 HE - Manual (Page 49)

8 Troubleshooting
49 E-812/816 Hot Extraction Operation Manual, Version B
8 .3 Too high/too low results
There are many reasons for too high or too low results even though the extraction process ran without
problems. The most important reasons are listed in the following:
Results too high
• Work with clean and dry hands and material (weighing and sample preparation).
• Dry the beakers completely after extraction until a constant weight is reached.
• Use clean and pure solvent.
• Make sure that the components in contact with solvent are out of solvent resistant material (solvent
resistant funnel, dispensette organic, for example).
Results too low
• Insufficient sample homogenisation
• Sample was wet before extraction.
• Fat is combusted during drying due to high temperature in the drying oven.
• Use clean and pure solvent.
Problems during hydrolysis with B-411/E-416
• If the hydrolysing temperature is too high fat of sample can combust or the sample solution can
boil over.
• If the hydrolysing time is too long sample fat might be destroyed.
• If the hydrolysing time is too short the fat is not unhinged completely of the matrix.
• If the temperature of the rinsing water (hydrolysis) is too hot, fat is washed out.
• If the celite content is too small the sample fat can not be bounded sufficiently.
• Fat can combust during too hot drying (too high temperature/power in microwave, drying oven or
vacuum drying oven).