Direct Method of Measuring the pH Value of Wood

Abstract

A direct method of measuring the pH value of wood substance is proposed in the paper. The achieved results were completed by determining the pH value on the wood surface using the contact method. Moreover, the results were compared to the results achieved using the indirect methods to determine the pH value in cold water, as well as hot water, extract of wood. Using the direct method for measuring the pH value in drilled fresh sawdust, the pH value of beech was 5.11, of birch was 5.29, of alder was 4.88, and of maple was 4.65. Following the achieved results, the possibility to measure the pH value using a fast, accurate method useful in practice complying with the condition of the minimum free water in wood (moisture content of wood above the fibre saturation point) was presented. The results of measurements of the pH value using the contact method on the wood surface showed that this method can be used in the case of coniferous as well as broadleaved trees with heartwood. The value of pH measured on the surface of pine was 4.50, of spruce was 4.79, of the heartwood of oak was 3.46, and of the sapwood of oak 5.04. The measurement of pH values of water extracts confirmed great dependence of measured values on the conditions of wood extraction.

Confocal spectral microscopy, a non-destructive approach to follow contamination and biofilm formation of mCherry Staphylococcus aureus on solid surfaces

“…Effect of acidic pH on fluorescence properties of fluorescent protein mCherry of S. aureus was studied at pH of 3.5, 4 and 6. These values were chosen because the ground wood samples of oak, Douglas fir and poplar had pH values of 3.8, 4.4, 6.4, respectively 21 .…”

“…Therefore, mCherry S. aureus was chosen in the present work to investigate red S. aureus bio-distribution on green wood and melamine surfaces. A critical point was the high acidic environment of wood 21 , for example, the pH of oak wood is 3.5, which could influence the investigation. However, we have demonstrated that strong acidic pH responsible for green fluorescence switch of mCherry could be avoided by using phosphate buffer for bacterial inoculation and the storage of inoculated wood.…”

Impact of Steaming Mode on Chemical Characteristics and Colour of Birch Wood

“…The sample was drilled using an electric drill machine, and the resulting sawdust was pressed back into the opening; subsequently, a piercing electrode was applied. After achieving appropriate contact between the sawdust and probe, changes in the pH value were recorded every 15 s for a 7-min period [16].…”

Chemical composition of Luffa aegyptiaca Mill., Agave durangensis Gentry and Pennisetum sp.

“… Nemli, Yıldız & Gezer (2008) stated that a lower pH in lignocellulosic materials may be attributed to presence of more amounts of extractives and resin acids. The acidic reaction of most tree species is caused by free acids and acidic groups easy to be separated, that is, especially by acetic acid and acetyl groups ( Geffert, Geffertova & Dudiak, 2019 ). Variations of pH along the stem have also been associated with the presence of extractives ( Campbell, Kim & Koch, 1990 ).…”