A simple and efficient headspace gas chromatographic method for the determination of carboxyl groups in nanofibrillated cellulose
2018
Wu, Na | Wan, Xiaofang | Liu, Baolian | Chai, Xin-Sheng
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.
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