Jasco J-1100 User Manual

3
E(LD) is defined by the following formula.
E LD LD cl( ) /=
(2-6)
where
c
: Concentration(mol/l)
l
: Cell length(cm)
These calculations can be performed using [processing]-[CD options]-[Optical Constant…] of
spectra analysis program.
The LD scale has been set at 0.133△OD (when two windows of the 45° quartz plates are
used) or 0.066△OD (when one window of the 45° quartz plate is used) at a wavelength of
500nm using a quartz plate tilted 45° with respect to incident light as sample.
1.1.3 Optical system
A schematic diagram of the optical system of the Model J-1100/1500 CD spectrometer is
shown in Figure 1.1.
M0
M1
LS1
LS2
M6
SH
S1
S2
S3
M2
M3
M4
M5
P1
F
P2
L
CDM
O-ray
E-ray
D
M
0
~ M6 : Mirrors O-ray : Ordinary ray
LS1 : Xenon lamp (for sample measurement) E-ray : Extraordinary ray
LS2 : Mercury lamp (for the instrument inspection) L : Lens
SH : Shutter F : Filter
S1 ~ S3 : Slits CDM : Modulator
P1 : First prism (horizontal optical axis) D : PMT
P2 : Second prism (vertical optical axis)
Note: In case of Model J-1100, there is not the M0 mirror.
Figure 1.1 Schematic diagram of optical system
Light source for measuring the sample is a xenon lamp. The light emitted from the xenon lamp
is focused by the M
1
mirror onto the S
1
entrance slit. The optical system between the S
1
entrance slit and the S
2
intermediate slit is referred to as the first monochromator, and the
optical system between the S
2
intermediate slit and the S
3
exit slit is referred to as the second
monochromator. Such an optical system, composed of two monochromators, is known as a
double monochromator. The ability of a double monochromator to reduce stray light makes it
indispensable for CD measurement.
The instrument uses crystal prisms (P
1
and P
2
) that have different axial orientations, so that the
light that passes through the monochromator is not only monochromated, but is also linearly
polarized in the horizontal direction.
This linearly-polarized light is modulated by the modulator into right and left circularly polarized
beams of light. The modulator subjects a quartz crystal to mechanical stress in order to
produce circular polarization in the quartz crystal, based on the principle of the Piezo effect.
When a sample with circular dichroism is placed in the sample chamber, the intensity, I, of the
transmitted light is modulated as shown in Figure 1.2.

Jasco J-1100 Specifications

General

Brand	Jasco
Model	J-1100
Category	Measuring Instruments
Language	English