Resumen Se realizó un análisis para determinar los principales componentes químicos de la madera de tres cabezas de vigas de pino procedentes del área de archivo del edificio histórico conocido como La Mitra, de la ciudad de Morelia, en Michoacán, México. Este análisis es complementario a uno previamente realizado, por medio de ultrasonido y con fines de conservación y restauración de estructuras de carácter histórico. Las vigas que aquí se analizaron forman parte del grupo que se estudió en esa primera fase; seleccionadas de forma aleatoria de un grupo de 40 y con dimensiones de 25 cm × 17 cm × 60 cm. Se tomaron muestras de albura y de duramen en dos secciones distintas (zona de empotramiento deteriorada y sana). Para cada viga se determinaron valores de pH, cenizas, análisis de las cenizas, sustancias extraíbles, holocelulosa y lignina. Los resultados encontrados fueron: pH de 3.20 a 4.67, cenizas 0.25% a 1.36%, con mayor concentración de oxígeno (3.36% a 6.64%), calcio (1.80% a 3.46%), carbono (1.18% a 3.45%), potasio (0.20% a 0.84%), aluminio (0.17% a 0.31%), silicio (0.15% a 0.59%) y magnesio (0.15% a 0.56%); solubilidad en sosa de (9.83% a 27.78%), extraíbles totales, en la extracción secuencial, la mayor solubilidad se obtuvo con acetona, (2.92% a 6.96%), seguido de agua caliente (0.25% a 7.49%), metanol (2.03% a 6.22%) y ciclohexano (0.98% a 2.66%); holocelulosa (68.22% a 84.01%) y lignina (24.19% a 31.83%). El pH, la solubilidad en sosa, la holocelulosa y la lignina presentaron una variación estadística significativa (P < 0,05) entre albura y duramen de las zonas sanas y deterioradas.
Abstract An analysis was carried out to determine the main chemical components of the wood of three pieces of pine beams from the archive area of the historic building known as La Mitra, in the city of Morelia, in Michoacán, Mexico. This analysis is complementary to one previously carried out, by means of ultrasound and for the purpose of conservation and restoration of historical structures. The beams that were analyzed here are part of the group that was studied in that first phase, randomly selected from a group of 40 and with dimensions of 25 cm × 17 cm × 60 cm. Sapwood and heartwood samples were taken in two different sections (decayed and healthy embedment area). For each beam, pH, ashes, ash analysis, extractable substances, holocellulose and lignin values were determined. The results found were: pH from 3.20 to 4.67, ashes 0.25% to 1.36%, with a higher concentration of oxygen (3.36% to 6.64%), calcium (1.80% to 3.46%), carbon (1.18% to 3.45%), potassium (0.20% to 0.84%), aluminum (0.17% to 0.31%), silicon (0.15% to 0.59%), and magnesium (0.15% to 0.56%); solubility in soda (9.83% to 27.78%), total extractables, in the sequential extraction, the highest solubility was obtained with acetone, (2.92% to 6.96%), followed by hot water (0.25% to 7.49%), methanol ( 2.03% to 6.22%) and cyclohexane (0.98% to 2.66%); holocellulose (68.22% to 84.01%) and lignin (24.19% to 31.83%). The pH, solubility in soda, holocellulose and lignin presented a statistically significant variation (P < 0.05) between sapwood and heartwood in healthy and deteriorated areas.