The invention relates to
melamine tail gas analysis, in particular to a quantitative
analysis method for isocyanato in
melamine tail gas. The quantitative
analysis method comprises the following steps of: S1, carrying out sampling; S2, carrying out pipetting; S3, accurately transferring 50.0 ml of a to-be-detected sample into an
iodine flask, adding 20 ml of an analytically pure
formaldehyde solution, dropwise adding a plurality of drops of a
phenolphthalein indicator, and neutralizing with a 1.0 mol / L NaOH
standard solution until the solution is light red; S4, heating the
iodine flask on an electric furnace until boiling for 1 minute; S5, plugging, cooling to
room temperature, not forming negative pressure in the flask, adding 5mL of a di-n-
butylamine toluene solution into the
iodine flask by using a transfer
pipette, and leaching the wall of the iodine flask by using 10ml of
toluene; S6, adding 50 ml of
acetone into a measuring cylinder, and subjecting the mixture to a standing reaction for 15 min at the
room temperature; S7, titrating excessive di-n-
butylamine by using a
potentiometric titration method or a
chromogenic titration method; and S8, calculating the content of isocyanato according to a
titration result in S7. The new quantitative
analysis method for isocyanato is provided through design, operation is easy, the result is accurate, and the method has popularization significance.