“吸光量”的原理、技术和应用  

PRINCIPLES AND PRACTICE OF “ABSORBABILITY”

作　　者：李酉开[1] 易小琳[1] 

机构地区：[1]北京农业大学

出　　处：《土壤学报》1995年第4期383-387,共5页Acta Pedologica Sinica

摘　　要：本文概述了吸光量的概念、原理、测试技术和一些应用实例。Absorbability (Q) is a new concenpt which is derived from absorbance of de-termining nitrate nitrogen in soil by UV spectrophotometry for characterizing thecontents of nitrate nitrogen and soluble organic nitrogen in soils. Absorbance indi-cates only the comcentration of a light-absorbing component in solution rather thanthe content of this component in sample (e. g., soil sample). Absorbability maybe used as an index of characterizing the content of a light-absorbing componentin sample.When a soil is extracted by an extractant, the absorbability (Q) of the soil ata particular wave length is directly proportional to the absorbance (A) and volume(V) of soil extract but inversely proportional to the mass(m) of soil sample andthe optical path length (b),Soil-Q = AV/bmwithin a certain range, the values of soil-Q possees additive property.The method of UV-absorbability is very simple, rapid, inexpensive, sensitiveand precise, and the results obtained are reliable. The results of our experimentshave shown that the soil absorbability values of total nitrogen, nitrate nitrogen, andsoluble organic nitrogen (soil-Q_T, -Q_(NO_3), and -Q_(OM).) extracted by electro-ultrafiltra-tion, 0.o1mol/L CaCl_2, and 0.01 or 0.05mol/L NaHCO_3 are closely correlated withthe content of extractable total nitrogen, nitrate nitrogen, and organic nitrogen (N_T,N_(NO_3), and N_(org)) determined by the Kjeldahi method or Technicon Autoanalyzer Te-chniqe, UV spectrophotometry or phenol disulphonic method, and Technicon Auto-analyzer techniqs, respectively, Therefore, the soil-Q values can really characterizethe content of different fractions of available nitrogen in soil. Although soil-Qvalues are provided with relative sense, the content of different forms of nitrogenin soil can be calculated by means of regression equation of these two variables.S

关 键 词：吸光度 吸光量 紫外光谱法 土壤 硝态氮 测定 

分 类 号：S158.2[农业科学—土壤学]