Total sulfite in cellulosics by ion exclusion chromatography with electrochemical detection
1991
Reim, R.E.
Total sulfite at concentrations < or equal to 50 ppm was determined in commercially available thixotropic materials based on methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) by extraction into an alkaline solution of 5% (w/v) Na2SO4 and subsequent separation by anion exclusion chromatography and electrochemical detection. Results were compared to those obtained by Monier-Williams distillation which was shown to suffer from low recovery, poor reproducibility and false positive response. Mean sulfite recovery, added at concentrations of 10-50 ppm SO2 was 91 +/- 11% based on 12 determinations. Analysis time for the chromatographic method was < 25 min/determination. Aldehydes did not interfere at concentrations < 100-fold excess.
显示更多 [+] 显示较少 [-]