AQ-00275-000, Rev. 3
1
Introduction
The traditional use of the spectrophotometer is to measure the transmittance of a clear or translu-
cent liquid or solid. Typical UV/VIS spectroscopy applications in this regard include reaction
kinetics, quantitative analysis or the simple identification of the chemical constituents in a sub-
stance. The measurement of reflectance offers an added dimension to the spectroscopy capabilities
of your spectrophotometer - your analysis is no longer limited to the portion of the beam that pen-
etrates the sample. Accordingly, you are no longer limited to samples that are clear or translucent.
The diffuse reflectance accessory (DRA) provides the means of measuring opaque, turbid and
reflecting substances using the same basic procedures used in traditional measurements.
Your DRA-CA-3300 is an integrating sphere accessory that replaces the sample compartment of
your spectrophotometer. An integrating sphere is a hollow optical device, either constructed from
or coated internally with a white diffusing material and fitted with the same detector as your spec-
trophotometer. At Labsphere, we use one of several proprietary reflective coatings in our reflec-
tance accessories, depending on the wavelength of your spectrometer and your application. The
integrating sphere collects the radiation from the sample and reference beams and measures the
signals for display by your CARY WinUV software.
Figure 1. The DRA-CA-3300 replaces the existing sample compartment of the
CARY 100 or CARY 300 spectrophotometers.