This paper reports on a headspace gas
chromatography method (HS-GC) for efficient determination of carboxyl groups in nanofibrillated cellulose (NFC). By pretreating the NFC suspension with a
strong acid cation exchange resin for 30 min, the
carboxyl groups in NFC were converted to the
carboxyl acids. The pretreated suspension was added
into a closed headspace sample vial containing
bicarbonate solution. By HS-GC measuring the CO2
produced from the reaction between carboxyl acids
and bicarbonate (10 min at 60 C), the content of
carboxyl groups in NFC can be determined. The
results showed that the relative standard deviation of
the method in the repeatability testing was\ 3.7% and
the limit of quantitation was about 0.1 mmol/g.
Relative differences between the HS-GC and the
reference (a conductometric titration) method were
within 15.0%. The present method is simple and
efficient, and suitable to be used for determining the
content of carboxyl groups in NFC in the related
applications

• A simple and efficient headspace gas chromatographic method for the determination of carboxyl groups in nanofibrillated cellulose