Of all the common laboratory test methods, the Kjeldahl method for determining nitrogen subjects the boiling flask to the most severe thermal and chemical abuse. These Pyrex® Kjeldahl flasks have tooled finished necks for extra strength and uniform rubber stopper fit. Wall thickness is controlled to offer the optimum balance between thermal shock and chemical resistance. They can be used in ASTM E-258 procedures. Reference: ASTM E-1377.
Note: Flask bottoms should not come in contact with the heating elements.