JP4897308B2 - Analysis equipment - Google Patents

Description

  The present invention relates to an analyzer that detects the amount of measurement light transmitted through a sample held in a container and measures the absorbance of the sample based on the amount of transmitted light.

  Conventionally, a sample in which a sample such as blood or urine and a reagent are mixed is stored in a measurement cell, and the stored sample is irradiated with measurement light and transmitted, and the absorbance of the sample is measured based on the amount of transmitted light. An analyzer for performing component analysis of a sample is known (see, for example, Patent Document 1). In such an analyzer, the measurement light transmitted through the sample is dispersed and received, and an intensity signal corresponding to the amount of transmitted light of the received measurement light is generated for each wavelength. The intensity signal is amplified by a log amplifier, and the amplified intensity signal is A / D converted and subjected to a predetermined calculation process to obtain the absorbance of the sample.

Japanese Patent Laid-Open No. 10-132735

  However, in the above-described analyzer according to the prior art, since the intensity signal is amplified by the log amplifier, there is a problem that the measurement accuracy of the absorbance decreases due to the influence of noise generated by the log amplifier.

  On the other hand, it is generally considered that a linear amplifier excellent in low noise performance and high-speed response is used for amplification of the intensity signal instead of the log amplifier. However, since the absorbance of the sample changes according to the logarithm of the magnitude of the intensity signal, in a general-purpose A / D converter (A / D converter), the sample component concentration is high and the absorbance is large. In addition, there is a problem that a desired measurement resolution with respect to absorbance cannot be obtained. On the other hand, when the number of bits of the A / D converter is increased, the intensity signal conversion processing time increases and the absorbance measurement time increases, which causes a problem that the throughput of the analyzer decreases.

  The present invention has been made in view of the above, and an object of the present invention is to provide an analyzer that can measure the absorbance of a sample at a desired speed and at a wide speed without reducing measurement accuracy. To do.

  In order to solve the above-described problems and achieve the object, an analyzer according to claim 1 is an analyzer that measures the absorbance of a sample held in a container, receives measurement light transmitted through the sample, Light receiving means for outputting an intensity signal corresponding to the transmitted light amount of the measurement light, a linear converter for linearly converting the intensity signal and outputting a level signal corresponding to the magnitude of the intensity signal, and the level signal as A / An A / D converter that performs D conversion, the number of bits of the A / D converter is determined based on the conversion resolution of the A / D converter, the optical path length of the container, and the absorbance in a predetermined measurement range. In the relationship with the level change amount of the level signal corresponding to a predetermined measurement resolution, it is the smallest integer that is not more than the maximum value of the level change amount, and the container corresponds to the minimum integer with the level change amount More than the conversion resolution It characterized in that it has an optical path length becomes.

In the analysis apparatus according to claim 2, in the above invention, the number of bits n of the A / D converter is such that the predetermined measurement range is OD _r , the predetermined measurement resolution is ΔOD, The minimum integer calculated by Equation 1 where P is the ratio between the level value of the level signal corresponding to the maximum transmitted light amount of the measurement light in the measurement range and the conversion range of the A / D converter, The optical path length L of the container satisfies Formula 2 when the bit number n is the minimum integer.

  In the analyzer according to claim 3, in the above invention, the number of bits of the A / D converter is 18, and the optical path length of the container is 0.5 mm or more and 3 mm or less. And

  According to a fourth aspect of the present invention, there is provided the analyzer according to the above invention, wherein the first condensing optical system that condenses the light in a predetermined wavelength region emitted from the light source into the sample, and the predetermined wavelength region transmitted through the sample. A second condensing optical system that condenses the light on the slit, and a spectroscopic unit that divides the light in the predetermined wavelength range that has passed through the slit for each wavelength, and condenses the light on the light receiving unit for each branched wavelength. And the light receiving means receives the light in the predetermined wavelength range collected for each wavelength by the spectroscopic means as the measurement light.

  According to a fifth aspect of the present invention, in the above invention, at least one of the first condensing optical system and the second condensing optical system is a parabolic mirror pair.

  According to the analyzer of the present invention, the absorbance of a sample can be measured widely and at high speed with a desired measurement resolution without degrading measurement accuracy.

  Hereinafter, preferred embodiments of an analyzer according to the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals.

(Embodiment)
FIG. 1 is a diagram showing a main configuration of an analyzer 1 according to an embodiment of the present invention. As shown in FIG. 1, the analyzer 1 dispenses a sample and a reagent as an analysis target into a measurement cell as a sample, and optically measures a reaction occurring in the dispensed measurement cell, A control analysis mechanism 21 that controls the entire analysis apparatus 1 including the measurement mechanism 11 and analyzes a measurement result in the measurement mechanism 11 is provided. The analyzer 1 automatically performs biochemical, immunological or genetic analysis of a plurality of specimens by linking these mechanisms.

  The measurement mechanism 11 roughly includes a sample transfer unit 12, a sample dispensing unit 13, reagent tables 14A and 14B, reagent dispensing units 15A and 15B, a reaction table 16, a photometric unit 18 and a cleaning unit 19. The control analysis mechanism 21 includes a control unit 22, an input unit 23, an output unit 24, and a storage unit 25. These units included in the measurement mechanism 11 and the control analysis mechanism 21 are electrically connected to the control unit 22.

  The sample transfer unit 12 includes a plurality of sample racks 12b that hold a plurality of sample containers 12a containing liquid samples such as blood and urine and sequentially transfer them in the direction of the arrows in the figure. The sample in the sample container 12a transferred to a predetermined position on the sample transfer unit 12 is dispensed by the sample dispensing unit 13 to the measurement cell 17 that is arranged and conveyed on the reaction table 16. The sample dispensing unit 13 includes an arm 13a that pivots in the horizontal direction and a pipette-like probe that is attached to the pivoting tip of the arm 13a in the vertical direction. The sample accommodated in the sample container 12a is aspirated by the probe. Dispensing is performed by discharging into the measurement cell 17 transported to a predetermined position on the reaction table 16.

  Each of the reagent tables 14A and 14B is formed in a circular shape in the horizontal plane, and is rotated in the circumferential direction by a driving mechanism (not shown) to hold a plurality of reagent containers 14Aa and 14Ba held along the circumferential portion. Rotate and move. As with the sample dispensing unit 13, each of the reagent dispensing units 15A and 15B includes arms 15Aa and 15Ba that pivot in the horizontal direction, and pipette-like probes that are vertically attached to the pivoting tip of each arm. The measuring cell 17 is aspirated by the probe with the reagent in the reagent containers 14Aa and 14Ba moved to a predetermined position on the reagent tables 14A and 14B and conveyed to the predetermined position on the reaction table 16. Dispense into.

  The reaction table 16 is formed in a circular shape in the horizontal plane, is rotated in the circumferential direction by a drive mechanism (not shown), is arranged along the circumferential portion, and rotates and conveys the plurality of measurement cells 17 in the circumferential direction. The reaction table 16 normally rotates and conveys the measurement cell 17 continuously in the clockwise direction in the drawing at a predetermined rotation speed, but the rotation speed and the rotation direction can be changed based on an instruction from the control unit 22.

  The photometry unit 18 irradiates the sample in the measurement cell 17 with measurement light in a predetermined wavelength region, and receives the measurement light transmitted through the sample, and measures the absorbance of the sample. The measurement result is output to the control unit 22 and analyzed. Details of the mechanism and operation of the photometry unit 18 will be described later.

  The cleaning unit 19 performs cleaning by sucking and discharging a sample in the measurement cell 17 that has been measured by the photometry unit 18 by using a nozzle (not shown) and injecting and sucking a cleaning liquid such as detergent or cleaning water.

  The control unit 22 is configured using a CPU or the like, and controls processing and operation of each unit of the analyzer 1. In particular, the control unit 22 includes an analysis calculation unit 22a. The analysis calculation unit 22a performs component analysis of a sample, that is, a specimen based on the measurement result acquired from the photometry unit 18. The control unit 22 acquires various information necessary for sample analysis, analysis operation instruction information, and the like from the outside through the input unit 23 configured using a keyboard, a mouse, and the like. In addition, the control unit 22 outputs various information including the analysis result of the sample to the output unit 24 configured using a display, a printer, a communication mechanism, and the like, and also stores the information configured using a ROM, a RAM, and the like. Record in section 25.

  In the analyzer 1 configured as described above, the sample dispensing unit 13 dispenses the sample in the sample container 12a to the plurality of measurement cells 17 that are sequentially conveyed in a row, and the reagent dispensing unit. After 15A and 15B dispense the reagents in the reagent containers 14Aa and 14Ba, respectively, the photometry unit 18 measures the absorbance of the sample in a state where the sample and the reagent are reacted, and the control unit 22 analyzes the measurement result. Thus, the component analysis of the specimen is automatically performed. Further, the cleaning unit 19 cleans the measurement cell 17 transported after the measurement by the photometry unit 18 is completed while transporting, so that a series of analysis operations are continuously repeated.

  The analyzer 1 includes two sets of the reagent table and the reagent dispensing unit, but may include one set or three or more sets depending on the analysis item or the like. Moreover, the reagent accommodated in each reagent container 14Aa, 14Ba is selected according to an analysis item etc., and may be the same or different. Furthermore, the analyzer 1 can also include a stirring mechanism (not shown) that stirs the measurement cell 17 when the sample and the reagent are dispensed. Note that the sample and reagent dispensing order for each measurement cell 17, the number of reagents dispensed to the same measurement cell 17, and the like can vary depending on the analysis item, reagent type, analysis protocol, and the like.

  Next, the photometry unit 18 will be described in detail. FIG. 2 is a diagram illustrating a main configuration of the photometry unit 18. As shown in FIG. 2, the photometry unit 18 includes a light source 31, lenses 32 and 33, a spectroscope 34, a photodetector array (PDA) 35, a current-voltage converter (I / V converter) 36, a wavelength selector switch 37, A A / D converter 38 and an absorbance calculation unit 39 are provided. The light source 31 and the lens 32 are provided inside the circular row of the measurement cells 17 arranged on the reaction table 16, and each part from the lens 33 to the absorbance calculation unit 39 is outside the circular row of the measurement cells 17. Is provided.

  The light source 31 emits measurement light in a predetermined wavelength range, and the lens 32 collects the measurement light emitted from the light source 31 and irradiates the sample SP in the measurement cell 17. The lens 33 condenses the measurement light transmitted through the sample SP and causes the measurement light to enter the spectroscope 34. The spectroscope 34 branches the incident measurement light for each wavelength, and the branched measurement light is reflected on the light receiving surface of the PDA 35. The light is collected for each wavelength. Here, an incandescent bulb such as a halogen lamp or a discharge lamp such as an Xe lamp is used as the light source 31, and a concave diffraction grating or the like is used as the spectroscope 34.

  The PDA 35 receives the measurement light collected by the spectroscope 34 and outputs an intensity signal that is a photocurrent corresponding to the amount of transmitted light of the measurement light through the sample SP. At this time, the PDA 35 receives measurement light for each wavelength branched by the spectroscope 34 and outputs an intensity signal for each wavelength. The I / V converter 36 as a linear converter linearly converts the intensity signal for each wavelength output from the PDA 35 into a current and voltage, and outputs a level signal corresponding to the magnitude of the intensity signal for each wavelength. To do. The wavelength changeover switch 37 selectively outputs a level signal for each wavelength output from the I / V converter 36 based on an instruction from the control unit 22.

The A / D converter 38 performs A / D conversion on the level signal of the analog signal selected and output from the wavelength selective switch 37 and outputs it as a level signal of a digital signal. At this time, the A / D converter 38 A / D-converts a level signal having a magnitude within a predetermined conversion range with a predetermined number of bits. The absorbance calculation unit 39 acquires the level signal output from the A / D converter 38, and uses the level value V of this level signal, the level value V ₀ of the reference level signal, and the optical path length L of the measurement cell 17, The absorbance OD of the sample SP is calculated by the following equation (1).
OD = (10 / L) log ₁₀ (V ₀ / V) (1)
The absorbance calculation unit 39 calculates the absorbance OD for each wavelength and outputs it to the control unit 22, and the analysis calculation unit 22a performs component analysis of the sample SP based on the absorbance OD for each wavelength.

The absorbance OD calculated by the equation (1) is the absorbance per 10 mm of the thickness of the sample SP in the optical path direction, and the optical path length L of the measurement cell 17 is the sample SP accommodated in the measurement cell 17 in the optical path direction. Thickness measured in units. On the other hand, the reference level signal is a level signal corresponding to the light amount of the measurement light immediately before entering the measurement cell 17, and corresponds to the maximum transmitted light amount as the transmitted light amount of the measurement light when absorption by the sample SP does not occur. It is a level signal. The level value V ₀ indicating the magnitude of the reference level signal is obtained in advance by, for example, measuring the transmitted light amount of the measurement light transmitted through the measurement cell 17 containing a reference liquid such as pure water having extremely low absorption. , Stored in the storage area of the absorbance calculation unit 39 or the storage unit 25. Further, the level value V is a level value corresponding to the amount of measurement light transmitted through the sample SP.

Here, when both sides of the formula (1) are differentiated, the following formula (2) is obtained.
From this equation (2), it can be seen that the change rate dOD / dV of the absorbance OD changes according to the level value V, and the magnitude thereof increases as the level value V decreases. That is, as the component concentration of the sample SP is higher and the transmitted light amount of the measurement light is smaller, the change rate dOD / dV of the absorbance OD is larger. Therefore, the conversion resolution of the level value V in the A / D converter 38 is smaller (higher). Otherwise, it can be seen that high resolution cannot be obtained with respect to the absorbance OD. On the other hand, when the number of bits of the A / D converter 38 is increased in order to reduce the conversion resolution of the level value V, the conversion processing time of the level value V is increased, and the measurement time of the absorbance OD in the photometry unit 18 is increased. I know that.

  Therefore, the number of bits of the A / D converter 38 according to the present embodiment is such that the conversion resolution of the level value V in the A / D converter 38 is within a predetermined measurement range of the optical path length L of the measurement cell 17 and the absorbance OD. The minimum integer that is equal to or less than the maximum value of the change amount of the level value V in the relationship with the change amount of the level value V corresponding to a predetermined measurement resolution is set. The measurement cell 17 has an optical path length L in which the amount of change in the level value V is equal to or greater than the conversion resolution corresponding to the minimum integer number of bits.

Such conditions for the A / D converter 38 and the measurement cell 17 were derived as follows. That is, first, as shown in FIG. 3, the measurement range of the absorbance OD using the A / D converter 38 and the conversion range of the level value V in the A / D converter 38 corresponding thereto are set. In FIG. 3, the axis indicating the absorbance OD is taken as the OD axis, and the axis showing the level value V corresponding to the absorbance OD is taken as the V axis. Further, the conversion range of the level value V corresponding to the entire measurement range OD _A absorbance OD to a total conversion range V _A, the absorbance OD ₀ absorbance across the entire measurement range OD _A, OD _max, the total conversion range V _A The level values at both ends are the level values V _max and V _min . Furthermore, 'and, the absorbance OD _0' predetermined absorbance OD ₀ within the entire measurement range OD _A and the level value V _mid corresponding to the partial measuring range OD _r absorbance OD determined by absorbance OD ₀ ', the provided Yes.

All measurement range OD _A, in formula (1), the level value V ₀ which is a reference level signal and the level value V _max, the level value V as a measure by the level value V _min, the following equation (3) Indicated by The total measurement range OD _A is a level value V in the case where the measurement light is maximum light transmission and level value V _max, the measurement range of the absorbance OD in the case of the absorbance OD ₀ = 0 corresponding to the level value V _max It corresponds to.
OD _A = (10 / L) log ₁₀ (V _max / V _min ) (3)

Further, the partial measurement range OD _r is obtained by setting the level value V ₀ of the reference level signal as the level value V _mid and the level value V as the measurement value as the level value V _min in the formula (1). 4). This partial measurement range OD _r is a measurement of the absorbance OD when the level value V when the measurement light reaches the maximum transmitted light amount is the level value V _mid and the absorbance OD ₀ ′ = 0 corresponding to this level value V _mid. Corresponds to the range.
OD _r = (10 / L) log ₁₀ (V _mid / V _min ) (4)

By subtracting Equation (4) from Equation (3) on both sides, the following Equation (5) is obtained.
_{OD A -OD r = (10 /} L) log 10 (V max / V mid) ··· (5)
This equation (5), using the ratio P between the level value V _mid and full conversion range V _A, the entire measurement range OD _A is represented by the following formula (6). However, the ratio P = V _mid / V _max is assumed here, assuming that the level value V _min ≈0 and the total conversion range V _A ≈V _max .
OD _A = OD _r + (10 / L) log ₁₀ (1 / P) (6)

The partial measurement range OD _r corresponds to a substantial absorbance measurement range set in consideration of the fact that the maximum transmitted light amount of the measurement light decreases with time according to the deterioration of the light source 31, and the ratio P corresponds to the margin portions measurement range OD _r corresponding to the entire measurement range OD _a.

On the other hand, the level value V is expressed by the following equation (7) by modifying the equation (1).
By differentiating both sides of the equation (7), the rate of change dV / dOD of the level value V with respect to the absorbance OD is expressed by the following equation (8), and further the equation (8) is modified to change the amount of change in the absorbance OD. The amount of change dV of the level value V with respect to dOD is expressed by Equation (9).

Variation dV level value V when the absorbance OD is the maximum absorbance OD _max in the entire measurement range OD _A is to the equation (9), the level value V ₀ = V _max, and the absorbance OD = OD _A, further absorbance by using the equation (6) as OD _a, represented by the following formula (10).

In order to make the measurement resolution of the absorbance OD smaller (higher), it is necessary to increase the amount of change in the level value V corresponding to the amount of change in the absorbance OD, and thus the amount of change represented by the equation (10). It is preferable that the absolute value of dV be a maximum value. The optical path length L for obtaining such a maximum value is given by the equation (12) by setting the differential value d (dV) / dL = 0 in the following equation (11) obtained by differentiating the equation (10). .
L = 10 / (OD _r · log _e 10) (12)
By substituting this equation (12) into equation (10), the maximum value | dV _M | shown in the following equation (13) is obtained.

A / D converter 38 is the maximum value | dV _M | To be able convert the converted resolution V _max / 2 ⁿ indicated by the bit number n of the A / D converter 38, the maximum value | dV _M | less It is necessary to. Therefore, the bit number n needs to satisfy the relationship represented by the following equation (14). Here, the level resolution V _min ≈0 and the total conversion range V _A ≈V _max , and the conversion resolution is V _max / 2 ⁿ .
When this equation (14) is solved for the number of bits n, the following equation (15) is obtained.
Further, by substituting the measurement resolution ΔOD necessary for measuring the absorbance OD in the photometry unit 18 into the change amount dOD, a necessary condition for the bit number n is obtained as the following equation (16).

Further, in the A / D converter 38 of n bits satisfying the equation (16), the necessary condition for the optical path length L for setting the change amount dV of the level value V to the conversion resolution V _max / 2 ⁿ or more is Based on 10), the following equation (17) is obtained.
Further, this equation (17) is rearranged to obtain the following equation (18).

In the present embodiment, from the necessary conditions derived as described above, the number of bits n of the A / D converter 38 is set to the smallest integer that satisfies Expression (16), and the measurement cell 17 satisfies Expression (18). It is assumed that it has an optical path length L. Thereby, the photometry unit 18 can measure the absorbance OD of the sample SP at a high speed with a predetermined measurement resolution ΔOD in a wide measurement range OD _r . In addition, the A / D converter 38 can be realized at low cost.

Here, a setting example of various parameters of the photometry unit 18 will be described more specifically. For example, in accordance with the characteristics of the sample SP, the total measurement range OD _A = 6 of the absorbance OD by the photometry unit 18 is set, and the partial measurement range OD _r = 3 as a substantial measurement range. Accordingly, the total conversion range V _A ≈V _max = 6 (V) of the A / D converter 38, the level value V _mid = 3 (V), and the ratio P = 0.5. Further, when the equation (16) is calculated with the measurement resolution ΔOD = 1/10000 necessary for the absorbance OD in the analysis of the sample SP, the number of bits is n ≧ 17.3. Thus, the number of bits n of the A / D converter 38 can be set to 18.

In addition, when the number of bits n = 18 and the relationship represented by Expression (18) is represented in a graph, it is as shown in FIG. In FIG. 4, a curve C1 shows a change of the right side of the equation (18) according to the optical path length L, and a straight line C2 is a value 1/2 ¹⁸ (= 3.8 × 10 ⁻⁶ ). The curve C1 and the straight line C2 intersect at an optical path length L = 0.46, 3.3 (mm). As a result, the optical path length L is 0.46 mm or more and 3.3 mm indicated by an arrow in the figure. It can be seen that the formula (18) is satisfied within the following range. In this case, the optical path length L of the measurement cell 17 is preferably set to 0.5 mm or more and 3 mm or less in consideration of a margin for manufacturing errors and the like.

Further, from FIG. 4, the curve C1 shows the maximum value at the optical path length L = 1.5 (mm). At this time, the conversion resolution V _max / 2 ⁿ of the A / D converter 38 is the change amount dV of the level value V. It can be seen that it has the most margin. That is, it can be seen that the optical path length L = 1.5 (mm) is the optimum value in the measurement cell 17.

FIG. 5 shows the amount of change dOD in the absorbance OD corresponding to the conversion resolution V _max / 2 ⁿ for each of the optical path lengths L = 0.46, 1.5, and 3.3 (mm) thus obtained. the is a graph showing a change with respect to partial measurement range OD _r. Curves C3 to C5 shown in FIG. 5 correspond to the optical path length L = 0.46, 1.5, and 3.3 (mm) in order. As can be seen from FIG. 5, the change amounts dOD shown by the curves C3 to C5 are all within the range of the partial measurement range OD _r = 0 to 3 and the measurement resolution ΔOD = 1/10000 (= 0.0001) or less. . It can also be seen that when the optical path length L = 1.5 (mm), the measurement resolution ΔOD generally has a margin within the same range.

The curves C3 to C5 shown in FIG. 5 are obtained as follows. That is, first, the following equation (19) is obtained by solving the equation (10) for the change amount dOD.
In this equation (19), the following equation (20) is obtained with the change amount dV = V _max / 2 ⁿ .
By substituting into this equation (20) the optical path length L = 0.46, 1.5, 3.3 (mm), the ratio P = 0.5, and the number of bits n = 18, the curve C3- Obtaining C5.

From the above specific example, by setting the bit number n of the A / D converter 38 to 18 and the optical path length L of the measurement cell 17 to 0.46 mm or more and 3.3 mm or less, preferably 0.5 mm or more and 3 mm or less. It can be seen that the photometry unit 18 can measure the absorbance OD of the sample SP with a predetermined measurement resolution ΔOD = 1/10000 or less in a wide measurement range OD _r = 3.

  Up to this point, the best mode for carrying out the present invention has been described as an embodiment. However, the present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention. is there. For example, in the above-described embodiment, the measurement light emitted from the light source 31 is collected by the lens 32 and is irradiated to the sample SP in the measurement cell 17. For example, as shown in FIG. It is also possible to collect measurement light using the mirror pairs 32A and 32B and irradiate the sample SP.

  Similarly, in the above-described embodiment, the measurement light transmitted through the sample SP is collected by the lens 33 and is incident on the spectroscope 34. For example, as shown in FIG. It is also possible to collect the measurement light by using the pairs 33A and 33B and make the measurement light enter the slit 34A and the concave diffraction grating 34B as a spectroscope.

  Further, preferably, the concave reflecting mirror pair 32A, 32B and the concave reflecting mirror pair 33A, 33B are each configured as a parabolic mirror pair. Thereby, each paraboloid mirror pair can easily reduce chromatic aberration and ray aberration (especially spherical aberration) as compared with the case where a lens is used. Measurement light can be irradiated with a small beam diameter. As a result, the absorbance can be measured with a smaller volume of the sample SP accommodated in the measurement cell 17.

It is a figure which shows the structure of the analyzer concerning embodiment of this invention. It is a figure which shows the structure of the photometry part shown in FIG. It is a figure which shows the correspondence of the measurement range of an absorbance, and the conversion range of the level value converted by an A / D converter. It is a figure which shows the relationship between the change of the level value according to optical path length, and conversion resolution. It is a figure which shows the relationship between the measurement range of light absorbency, and variation | change_quantity. It is a figure which shows the modification of a structure of a photometry part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Analyzer 11 Measurement mechanism 12 Specimen transfer part 12a Specimen container 12b Specimen rack 13 Specimen dispensing part 13a Arm 14A, 14B Reagent table 14Aa, 14Ba Reagent container 15A, 15B Reagent dispensing part 15Aa, 15Ba arm 16 Reaction table 17 Measurement cell DESCRIPTION OF SYMBOLS 18 Photometry part 19 Washing part 21 Control analysis mechanism 22 Control part 22a Analysis calculation part 23 Input part 24 Output part 25 Storage part 31 Light source 32, 33 Lens 32A, 32B, 33A, 33B Concave reflector 34 Spectroscope 34A Slit 34B Concave diffraction Lattice 35 PDA
36 I / V converter 37 Wavelength changeover switch 38 A / D converter 39 Absorbance calculation unit SP Sample

Claims (5)

An analyzer for measuring the absorbance of a sample held in a container ,
Light receiving means for receiving the measurement light transmitted through the sample, and outputs an intensity signal corresponding to the transmitted light amount of the measuring light,
A linear transducer of the intensity signal to linear transformation, and outputs a level signal corresponding to the magnitude of the intensity signal,
Said level signal and an A / D converter for converting A / D,
The number of bits of the A / D converter, converts the resolution of the A / D converter, and the optical path length of the vessel, the level change of the level signal corresponding to a predetermined measurement resolution in a predetermined measuring range of the absorbance relative to the amount, the smallest integer equal to or less than the maximum value of the level variation,
The analyzer has an optical path length in which the level change amount is not less than the conversion resolution corresponding to the minimum integer. The number of bits n of the A / D converter is the smallest integer calculated by Equation 1.
The optical path length L of the container satisfies Formula 2 when the bit number n is the minimum integer :
Equation 1 and Equation 2, the predetermined measurement range and OD _r, the predetermined measurement resolution and .DELTA.OD, level values of the level signal corresponding to the maximum light transmission of the measuring light in the predetermined measurement range Based on the assumption that the ratio P is expressed by P = Vmid / Vmax under the assumption that the level value Vmin≈0 and the total conversion range VA≈Vmax, where P is the ratio of the A / D converter to the conversion range. The analyzer according to claim 1, wherein the analyzer is derived .
The number of bits of the A / D converter is 18,
The analyzer according to claim 1 or 2, wherein the optical path length of the container is 0.5 mm or more and 3 mm or less. A first condensing optical system that condenses light in a predetermined wavelength range emitted from a light source into the sample;
A second condensing optical system that condenses the light of the predetermined wavelength range that has passed through the sample onto a slit;
With branches the light of the predetermined wavelength region having passed through the slits for each wavelength, further comprising a spectroscopic means for focusing on said light receiving means for each branched wavelength,
The analyzer according to any one of claims 1 to 3, wherein the light receiving unit receives the light in the predetermined wavelength range collected for each wavelength by the spectroscopic unit as the measurement light.   5. The analyzer according to claim 4, wherein at least one of the first condensing optical system and the second condensing optical system is a parabolic mirror pair.