摘要
光度法工作曲线不成线性关系的情况多数是由体系存在逐级配合物所致。为获得线性关系,有些作者提出在两逐级配合物的互变等色点波长测量,认为这样可以避免同时生成第二配合物的影响,但没有深入的理论分析。作者之一曾试验过上述办法,未能得到直线。鉴于此法时见有人引用,我们认为有深入探讨并加以澄清的必要。本文通过实验与理论分析,证明此法在多数情况下仅可改善线性关系,但不能得到直线。经进一步研究,找到了这个问题的另外解决办法。
If the deviation of calibration curve from linearity in spectrophotometry is generated
by the simultaneous presence of second complex in a stepwise complex system, it has been
demonstrated theoretically that a straight line can not be obtained by measuring at the
wavelength of the isosbestic point of the two stepwise complexes. Because this wavelength
only provides a condition, i. e. ε_(1∶2)=2ε_(1∶1), and according to the absorbance formula of a
system in which both 1:2 and 1:1 complexes ara present at the same time, a straight line
can be obtained only when the requirement ε^(1∶3)= ε^(1∶1)+ε~L is met. So, it is necessary to
find another wavelength to meet this requirement. Now, we have found this wavelength
theoretically and use it in soandium-Xylenol system. As a result, a calibration curve
with satisfactory linear relationship has been obtained.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1989年第7期694-698,共5页
Acta Chimica Sinica
基金
中国科学院科学基金
