T. D. Harris Bell Labcratories Murray Hill, NJ. 07974
High-Sinsitivity Spectrophotomdry Quantitative analysis by solution spectrophotometry has been in continnous practice for more than a century ( I 1. Instrumental design has remained conceptually stable since the early part of this century. However, the advent of stable electronics and reliable lasers has spawned a group of techniques for measuring absorbance that provides a quantum leap in spectrophotometric sensitivity. The exceptional sensitivity available from a wide variety of methods is illustrated in Table I. This high sensitivity has not yet been aiven enouah attention bv
:
I. Absorptioil
:tion Limits in Solut D.,~ion limn (M)
Method
;onventionai transmission .aser intracavity nterlerometry ahotothermai dPfleCtinn Pholoacoust~i Thermal lens
1X i O F
sx
10-6
lo-' I
x
1n-7
