JPH0233149Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the sensitivity of an infrared spectrophotometer, and particularly to a single comb shape used as a dimmer.

With the advancement of liquid chromatography technology, various detectors for detecting separated components have been used, including infrared spectrophotometers, visible ultraviolet spectrophotometers, and fluorescence spectrophotometers. Among them, methods using infrared spectrophotometers have recently attracted attention for use as detectors in high-performance liquid chromatography. However, if a conventional infrared spectrophotometer is applied as is, the sensitivity is insufficient, and unless the sensitivity is increased by some method or means, the range of use is limited, and it cannot be used generally as a detector for high performance liquid chromatography. It is difficult. Therefore, the applicant first arranged a plurality of dimming means in the light beam on the reference side,
As one of these, we proposed an infrared spectrophotometer that consists of a single comb and expands the dynamic range of the extinction rate.
Note that the dynamic range referred to here means the amount of movement of the optical comb, and expanding the dynamic range means the relationship between the amount of attenuation of transmitted light and the amount of movement of the optical comb (attenuator). This means increasing the amount of movement of the optical comb relative to the amount of change in transmittance. However, with this method, high sensitivity can be obtained when there is little change in absorption, but when there is a large amount of absorption, the optical comb scales out, putting a mechanical burden on the comb mechanism, and It was not possible to see the spectral shape of large samples in terms of wavenumbers.

Therefore, the object of the present invention is to obtain a single comb mechanism that eliminates the above-mentioned drawbacks. In other words, the high-sensitivity infrared spectrophotometer according to the present invention is characterized in that a certain range of one comb has a shape that expands the dynamic range, and another range has a shape that is close to a normal range. .

Embodiments of the present invention will be described in more detail below with reference to the drawings.

In Fig. 1, 1 is the optical axis, 3 is the entrance slit of the spectrometer, and a comb 2 is placed on the optical axis 1 in front of the entrance slit 3 to expand the dynamic range of the attenuation rate. The so-called optical zero position measurement system is constructed by moving in and out. In the present invention, one comb 2 has a shape as shown in FIG. Figure 2 a is the first
In the embodiment, a certain range 4 of the comb 2 has a shape that increases the dynamic range, and another range 5 has a shape that becomes a normal range. For example, the light reduction rate of one comb is 10%.
If so, in the transmittance range of 90 to 100%, the shape expands the dynamic range, and in the transmittance range of 0 to 90%, which corresponds to the remaining 90% of light attenuation, the shape is in the normal range. By changing the ratio of the lengths of both ranges 4 and 5 and their respective slopes, the attenuation rate and the magnitude of the dynamic range can be selected in accordance with the desired measurement. FIG. 2b shows a second embodiment in which the temperature distribution characteristics of the light source are considered. In this example, the lengths and slopes of the dynamic range range 4 and the normal range range 5 are the same as in the first embodiment, but a gap 6 is formed in the normal range range 5. In the above embodiment, one comb 2 is divided into two parts, but the shape division of the comb is not limited to this. FIG. 2c shows an embodiment in this case, in which one comb 2 is composed of three parts: a first dynamic range range 4, a second dynamic range range 4', and a normal range range 5. . The third embodiment of FIG. 2c may be provided with a gap 6 as shown in FIG. 2b.

By configuring the single comb 2 in this way,
When the absorption is small, the dynamic range range 4 functions and high sensitivity is obtained, while when the absorption is large, the normal range range 5 functions. Therefore, the optical comb does not scale out, preventing mechanical stress from being applied to the comb mechanism, and furthermore, it becomes possible to measure spectra based on wave numbers even for samples with large absorption changes.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a comb portion of a high-sensitivity spectrophotometer according to the present invention, and FIGS. 2 a, b, and c are diagrams showing respective embodiments of the shape of a single comb used in the present invention. 1...Optical axis, 2...Single comb, 3...Inlet slit, 4...Dynamic range range, 5...Normal range range, 6...Gap.

Claims (1)

[Scope of utility model registration request] In an infrared spectrophotometer using a double beam optical zeroing method, which uses a single optical comb as a light attenuator to expand the dynamic range of the light attenuation rate, 1.
A high-sensitivity infrared spectrophotometer, characterized in that the main comb is composed of a plurality of parts having different amounts of change in attenuation rate with respect to the amount of movement of the single comb.