Determination of boron levels in solution and in treated wood
F J Romero, P Vinden, P Kho
Four methods of measuring boron levels in solutions were investigated. The methods compared included the azomethine-H method which is commonly used in soils and plant tissues, the methods outlined in the Australian Standard AS 1605 (1974) and in Wilson (1958), and the atomic absorption spectrophotometry method. Defect-free radiata pine (Pinus radiata D. Don) sapwood and wood flakes were treated to different percentage boric acid equivalent (%BAE). A slightly acidic aqueous medium was used to extract boron from the samples. Extracts were analysed using the azomethine-H and carmine methods. The recovery and coefficient of variation were calculated and discussed. Results confirmed that all methods can be used for measuring boron in solution and wood samples at the range of%BAE investigated. However, the azomethine-H method was found not only to be the simplest and quickest but the most accurate method. It was also found that wood extractives in the wood did not affect the results.