Abstract
The studies covered laboratory, pilot and industry scale
instrumentation, method development and process sample measurements with
various capillary electrophoresis (CE) instruments. The research started by
modification of commercial CE apparatus for on-line sampling and on-line
sample pre-treatment. Afterwards, the studies were performed with
process-scale designed on-line CE systems. The instruments were used in
on-line mode, even under industrial process conditions, when studying sulphur
compounds at above 100 oC temperatures. The projects were challenging, since
many of the analytes exhibit weakly acidic properties and some of them were
only totally ionized in alkaline solutions. Direct UV detection of the
analytes was achieved by in-capillary complex formation, but mainly the
analytes were studied using indirect detection techniques. In on-line CE
instrument, contactless conductivity detection (CCD) was used. The methods
were capable for monitoring and determination of inorganic and organic
compounds from different process waters. The tests we made by coupling the
instruments in on-line with paper machines and in analyzing ions from the wet
end waters. The technology and methodology could be used to monitor
formaldehyde as the biocide chemical in wire washing and, in general, to
observe process disturbances resulting from concentrations for periods between
two weeks and one month at paper and pulp mills in Finland. As to the pulp
samples, they were digested using sample preparation. The solution obtained
from the procedure was analyzed. Mainly the interest was the metal ions in the
pulp and the performance of the bleaching chemicals, but also amounts of
carbohydrates in pulp cooking conditions. The studies with off-line and
on-line techniques convinced that the ionic compositions changed when the
samples were taken to laboratory measurements. High temperature analysis and
on-line determination can be used to avoid changes in the sample, which occur
during sample cooling and transportation (precipitation, oxidation, chemical
reactions, etc.) As a conclusion, the research on development and testing of
the instruments showed that CE could be used for troubleshooting purposes of
processes (quality of the product and performing of machine condition).
| Original language | English |
|---|---|
| Title of host publication | 4th Pulp and Paper Chemical Analysis Seminar, September, Stockholm, Sweden |
| Publisher | Skogs- och träforskningsinstitutet |
| Publication status | Published - 2007 |
| MoE publication type | A4 Article in a conference publication |
Keywords
- Analysis
- pulp and paper