Non-Destructive Method for Alkaline Reserve Determination in Paper Diffuse Reflectance Infraded Fourier Transform Spectroscopy
| Main Authors: | , , |
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| Format: | Article |
| Language: | English Slovak |
| ISSN: | ISSN 0034-5806 |
| Online Access: | http://www.viks.sk/chk/res_1_04_47_67.doc |
| Abstract: | SUMMARIES. DRIFTS was applied to the quantita-tive analysis of magnesium carbonate content in papers treated with non-aqueous deacidifying solution. The method proved to be reasonably accurate for papers which are susceptible to im-pregnation, so that carbonate deposits áre evenly distributed throughout the paper (or its surface, where the actual measurement takes plače). The curve-fitting was performed by classical least-squares technique, using several sets of spectra from papers loaded with O to 7% (w/w) MgCO3. The method is applicable to low surface sized papers, the spectra of which are not very different from that of pure cellulose. Compared with the Standard method fór measuring alkaline reserve, based on acid-base titrimetry, DRIFT spectrometry provides a non-destructive, fast, clean method capable of giving a lot of information about the reserve distribution on the treated materials; so it can complément the current deacidification quality control methods (surface and water extract pH, DPv, mechanical tests, SEM-EDX, ICP, etc.). CONCLUSIONS. Quantitative determination of alkaline reserve by diffuse reflectance infrared spectroscopy (DRIFTS) is a non-destructive method, which provides reasonably accurate results in a quick and simple way. Each individual result obtained corresponds to the MgCO3 mass deposited in the surface layer of the paper, over a round spot of 0.8 mm diameter. The results will be more accurate as the sample to be measured and the paper used to prepare the calibration standards are sirnilar, and because of the need to be more careful in the preparation procedure. The method is intended especially fór papers the reflection spectra of which do not differ very múch from that of cellulose and the absorbency of which al-lows good impregnation by non-polar solutions. Because of the interferences encountered the method is not recommended for supercalendered or heavily coated papers, the reflection spectra of which be-long to the surface size instead of the cellulose support. DRIFTS technique al-lows a quick and sure identification of such papers. If a wide set of calibration methods is available, valid for the great mass of papers suitable for deacidification, the method may become a routine for quality control. |
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| ISSN: | ISSN 0034-5806 |
