JP2013053905A - Hydride generation mercury measurement apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydride generation mercury measurement apparatus capable of reducing a temperature difference between respective samples by uniformly heating the multiple samples, enabling highly accurate analysis, and shortening a cooling time after heating.SOLUTION: The hydride generation mercury measurement apparatus is the apparatus for performing the preprocessing of multiple samples S with the use of a sample preprocessor 1. The sample preprocessor 1 includes: a reagent dispensation device 2 for dispensing reagents into sample containers 10 with the samples S contained therein; a turn table 12 that has ring shape holding parts 122 for removably holding the sample containers 10 by ring shape arrangement around a vertically axial center 121 and exposing at least the upper parts of the sample containers 10, and is rotated around the axial center 121; a heater 13 arranged to partially face the lower surfaces of the ring shape holding parts 122 and heating by non-contact the ring shape holding parts 122 positioned immediately above; a temperature sensor 17 for measuring the temperature of the ring shape holding parts 122; and temperature adjustment means 18 for adjusting the temperature of the samples S on the basis of the measured temperature of the ring shape holding parts 122.

Description

  The present invention relates to a reduced vaporized mercury measuring apparatus for measuring mercury in a sample by generating mercury gas by a reduced vaporization method.

  2. Description of the Related Art Conventionally, there is known a reduction vaporization measuring apparatus that measures mercury in a sample by generating mercury gas by a reductive vaporization method after pretreatment of the sample. This equipment uses pre-treatment of samples such as factory effluent, soil elution water, drinking water, river water, rain water, lake water, etc., and then generates mercury gas by the reductive vaporization method. It measures mercury and automatically pre-processes the sample. As specified in the official method (JIS K 0102), mercury in the sample is injected with a reagent such as sulfuric acid or nitric acid into the sample. After predetermined treatment, the sample is kept at 95 ° C. for 120 minutes, and then cooled. Then, mercury gas is generated by the reductive vaporization method and measured by the atomic absorption method.

  An apparatus for measuring reduced vaporization with an automatic pretreatment mechanism that automates this series of steps is known (Patent Document 1). A schematic diagram of the entire apparatus is shown in FIG. As shown in FIG. 4, this apparatus includes a sample stage 12 made of an aluminum block that heats a sample stored in a sample container 10. This sample stage 12 is fixed at a predetermined location in the apparatus, and in order to heat the sample and maintain it at 95 ° C. for 120 minutes, a plurality of heaters 13 are connected to the sample container 10 and the sample from the side of the aluminum block of the sample stage. The sample container 10 is heated by being inserted into the gap between the container 10 at regular intervals and surrounded by a heat insulating material. After the heating, the cooling fan 14 for cooling the sample accommodated in the sample container 10 is disposed below the sample stage 12 to cool the sample stage 12 from below (FIG. 3).

JP 2006-98400 A

  However, in the apparatus described in Patent Document 1, a plurality of heaters 13 are inserted at regular intervals from the side of the aluminum block of the fixed sample stage into the gap between the sample container 10 and the sample container 10 and heated by heat conduction. Therefore, heating unevenness occurred, and the temperature between the samples was likely to vary depending on the position where the sample container 10 was held on the sample stage. Further, the entire sample container 10 is surrounded by the heat insulating material of the outer frame of the sample stage, it is difficult to dissipate heat in a short time, the cooling fan 14 is disposed below the sample stage 12, and the air blown by the cooling fan 14 is blown by the sample container 10. However, it took a long time to cool the sample accommodated in the sample container 10.

  The present invention has been made in view of the above-mentioned conventional problems. The samples accommodated in a plurality of sample containers are uniformly heated to greatly reduce the temperature difference between the samples, thereby enabling highly accurate analysis. It is an object of the present invention to provide a reduced vaporized mercury measuring apparatus in which the sample container 10 can easily dissipate heat and the cooling time after heating can be shortened.

  In order to achieve the above object, the reduced vaporized mercury measuring apparatus of the present invention generates a mercury gas by a reduced vaporization method after pretreatment of a plurality of samples by a sample pretreatment device, and in each sample. A reduced vaporization mercury measuring device for measuring mercury, wherein the sample pretreatment device is configured to vertically connect a reagent dispensing device for injecting a plurality of reagents into each of a plurality of sample containers containing samples, and a plurality of sample containers. A turntable having an annular holding portion that is detachably held in an annular arrangement around a direction axis and exposes at least an upper portion of the sample container, and is rotated around the axis, and a lower surface of the annular holding portion A heater that is disposed in opposition to a part of the annular holding part and that heats the part of the annular holding part located immediately above, a temperature sensor that measures the temperature of the annular holding part in a non-contact manner, and the temperature sensor Said ring Based on the temperature of the holding portion and a temperature adjusting means for adjusting the temperature of the sample by controlling the heating value of the heater.

  According to the reduced vaporized mercury measuring apparatus of the present invention, the turntable having an annular holding portion is rotated, whereby the entire annular holding portion holding the sample container is heated by radiant heat from the heater in a non-contact manner. Therefore, heating unevenness does not occur in the annular holder that is a heating medium, the samples stored in multiple sample containers are heated uniformly, the temperature difference between each sample is extremely small, and high accuracy analysis is performed. Can do. Furthermore, since at least the upper part of the sample container is exposed from the annular holding part, the sample container can easily dissipate heat, and the cooling time after heating can be shortened.

  In the reduced vaporization mercury measuring apparatus of the present invention, it is preferable that the annular holding part exposes 1/2 to 3/4 of the total height from the upper end of the sample container. With this configuration, since more than half of the sample container is exposed from the annular holding part, the sample container can more easily dissipate heat, and the cooling time after heating can be further shortened.

  In the reduced vaporized mercury measuring apparatus according to the present invention, it is preferable that the apparatus includes a blower unit or an exhaust unit that air-cools the annular holder and the sample container from the side. With this configuration, the air blowing means or the exhaust means can efficiently cool the annular holding portion and the exposed portion of the sample container, so that the cooling time after heating can be further shortened.

It is the schematic of the reductive vaporization measuring apparatus of embodiment of this invention. It is a top view of the turntable of the same apparatus. It is the schematic of the conventional reductive mercury measuring apparatus. It is a top view of the sample stage of the same apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a reduced vaporization measuring apparatus according to an embodiment of the present invention. This apparatus includes a sample pretreatment apparatus 1 including a reagent dispensing apparatus 2, a mercury detection apparatus 3, and a personal computer (control unit) 4.

  The sample pretreatment apparatus 1 of the present apparatus automatically performs sample pretreatment. A plurality of sample containers 10 and a plurality of reagent dispensing apparatuses 2 for injecting a plurality of reagents into each of the plurality of sample containers 10. The sample container cap 11 through which the tube 15 for sample dispensing is held, the sample container cap 11 is attached to the distal end portion, and a vertical axis that rotates and moves up and down is attached to the proximal end portion. A sample container cap drive arm (not shown) that pivots 11 up and down, a plurality of sample containers 10 that are detachably held in an annular arrangement around a vertical axis 121 and that exposes at least the upper part of the sample container 10 The turntable 12 having the holding portion 122 and rotated around the axis 121, the annular holding portion that is disposed to face a part of the lower surface of the annular holding portion 122 and is located immediately above The heater 13 for heating the portion 22 in a non-contact manner, the temperature sensor 17 for measuring the temperature of the annular holding portion 122 in a non-contact manner, and the amount of heat generated by the heater 13 based on the temperature of the annular holding portion 122 measured by the temperature sensor 17. A temperature adjusting means 18 for adjusting the temperature of the sample S by controlling, and a blowing means 14 for air-cooling the annular holder 122 and the sample container 10 from the side are provided.

  In addition to this, the sample pretreatment device 1 of the present apparatus includes a light sensor 7 that detects a change in color density of potassium permanganate injected from the sample container cap 11 into the sample container 10, an automatic cleaning device 8, and a sample S in front of the sample S. An exhaust fan (not shown) for exhausting acid vapor generated during the treatment is provided. The sample container 10 is, for example, a test tube.

  FIG. 2 is a plan view of the turntable 12. The portion A shows the sample container insertion hole 124, but the portion B is shown with the sample container insertion hole 124 omitted to make it easier to see FIG. Yes. As shown in FIG. 2, the turntable 12 holds a plurality of sample containers 10 (FIG. 1) so as to be removable in an annular arrangement around a vertical axis 121 and exposes at least the upper part of the sample container 10. A holding portion 122 and a circular concave portion 123 centered on the axis 121 are formed on the inner diameter side of the annular holding portion 122 and rotated around the axis 121. The sample container 10 is detachably held in the sample container insertion hole 124 of the annular holding part 122. As shown in FIG. 1, the turntable 12 is connected to a motor 126 that rotates the turntable 12 at an axis 121 and is driven to rotate about the axis 121. The annular holding part 122 preferably exposes 1/2 to 3/4 of the total height from the upper end of the sample container 10, and here, 3/4 of the total height is exposed.

  The turntable 12 is made of, for example, an aluminum block, and has an annular holding portion 122 that is a heating medium heated by the heater 13, for example, black anodized so that the surface becomes black with high heat absorption efficiency and heat dissipation efficiency. The sample S in the sample container 10 held by the annular holding part 122 can be heated and cooled in a short time. Note that the turntable 12 may be a circular plate that does not have the circular concave portion 123 and has the upper end of the annular holding portion 122 as a whole height, and may have any structure as long as the rotating shaft of the motor 126 is attached.

  The heater 13 is formed by a heating element 131 that is two rod-shaped infrared heaters, and a semi-cylindrical heat reflecting plate 132 that is disposed so as to surround the infrared heaters. The heater 13 is attached from below to the opening of the turntable frame 125 disposed so as to cover the lower part of the turntable 12, faces a part of the lower surface of the annular holding part 122, and the longitudinal direction of the heater 13 is annularly held. It arrange | positions so that the chord direction of the outer periphery of the part 122 may be arrange | positioned, and the part of the cyclic | annular holding | maintenance part 122 located immediately above will be heated by non-contact.

  The temperature sensor 17 is attached from below to the opening of the turntable frame 125 facing the attachment position of the heater 13 with the vertical axis 121 interposed therebetween, and measures the temperature of the annular holding part 122 in a non-contact manner. The temperature adjusting unit 18 adjusts the temperature of the sample S by controlling the amount of heat generated by the heater 13 based on the temperature of the annular holding part 122 measured by the temperature sensor 17.

  The cooling fan which is the air blowing means 14 is disposed on the side and upper side of the heater 13 so that the center height of the air blowing means 14 coincides with the height of the upper end of the annular holding portion 122. The sample container 10 is air-cooled from the side. By this air cooling, the sample S accommodated in the sample container 10 is cooled via the annular holding part 122 and the sample container 10. Note that an exhaust unit may be provided instead of the blower unit 14.

  The automatic cleaning device 8 automatically cleans the sample container cap 11. The sample container cap 11 is moved on the turntable 12 by a sample container cap drive arm (not shown) and injected from the sample dispensing device 2. After washing in the rinse bottle 16 containing distilled water, the washing liquid in the rinse bottle 16 is drained.

The reagent dispensing device 2 injects a plurality of reagents into each of the plurality of sample containers 10 in which the sample S is accommodated. The reagent dispensing apparatus 2 is connected to the sample container 10 via a tube 15, and a predetermined amount of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), permanganese as a dispensing liquid to the sample container 10. Potassium acid (KMnO ₄ ) solution, potassium peroxodisulfate (K ₂ S ₂ O ₈ ) solution, hydroxylammonium chloride (HONH ₃ Cl) solution, tin chloride (SnCl ₂ ) solution, distilled water (H ₂ O) are for example tube pumps Dispensing by a dispensing method (not shown). The stannous chloride (SnCl ₂ ) solution is used as a reducing agent in the reductive vaporization method, the hydroxylammonium chloride (HONH ₃ Cl) solution is used as a reducing agent, and at the same time as a rinse for washing the sample container. Instead of the hydroxylammonium chloride (HONH ₃ Cl) solution of the reagent, a hydroxylammonium sulfate ((HONH ₃ ) ₂ SO ₄ ) solution may be used.

  The atomic absorption spectrometer, which is the mercury detector 3, measures the mercury gas generated by the sample pretreatment device 1, and includes an absorption cell 21, two photoelectric tubes 22, a preamplifier 23, a processing unit 24, a low-pressure mercury discharge tube. 26, a dehumidifier 28, a drain tank 29, a filter 30, and an air pump 31.

  The control unit (personal computer) 4 controls, for the sample pretreatment device 1, detection control of color density change of the sample S in the sample container 10 by the optical sensor 7, control of each processing time using a timer (not shown), a turntable In addition to the control of the rotational speed of 12 and the control of the temperature adjusting means 18, the entire apparatus including the reagent dispensing apparatus 2 and the mercury detection apparatus 3 is controlled.

  An operation of the reduced vaporized mercury measuring apparatus of the present embodiment will be described. This operation is performed according to a procedure based on a program stored in the control unit 4.

First, a plurality of reagent injections are started from the sample container cap 11 conveyed by the sample container cap drive arm. Reagents of sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), and potassium permanganate (KMnO ₄ ) solution are added to the sample S, and a stirrer 35 (FIG. 2) provided below the sample container 10 at the reagent injection position. ), The stirring bar (not shown) placed in the sample container 10 is rotated and stirred for 15 minutes. At this time, the light sensor 7 detects the red-purple shade change of potassium permanganate. When the red purple color of potassium permanganate disappears, that is, when the undegraded sample remains, the potassium permanganate solution is added in small portions until the red purple color of sample S lasts 15 minutes. The reagent injection / stirring is sequentially performed for a large number of samples by rotating a turntable 12 in which a large number of sample containers 10 are held in an annular arrangement. In this way, after the reagent is injected, the change in reddish purple density of the potassium permanganate in the sample container 10 is automatically detected.

Next, a potassium peroxodisulfate (K ₂ S ₂ O ₈ ) solution is added to the sample S. When the potassium peroxodisulfate (K ₂ S ₂ O ₈ ) solution is added, the control unit 4 controls the temperature adjusting means 18 and the motor 126 that rotates the turntable 12, the heater 13 starts heating, and the turntable 12 is rotated at a constant speed of, for example, two rotations per minute, and the entire annular holding part 122 is heated. In this way, the amount of heat generated by the heater 13 is controlled based on the temperature of the annular holding part 122 measured by the temperature sensor 17 while the turntable 12 is rotated, so that the sample S contained in the sample container 10 is controlled. And the sample is pretreated automatically by heating at about 95 ° C. for 2 hours.

  When the turntable 12 having the annular holding part 122 is rotated, the entire annular holding part 122 that holds the sample container 10 is heated by the radiant heat from the heater 13 in a non-contact manner. Uneven heating does not occur in the holding part 122, and the sample S accommodated in the plurality of sample containers 10 is heated uniformly, and the temperature difference between the samples is extremely reduced.

  When the heating step is completed, the heater 13 is turned off, and the air blower 14 blows air to cool the turntable 12 and the sample container 10 to room temperature while the turntable 12 continues to rotate. The rotation of the turntable 12 in the cooling process may be the same rotational speed as in the heating process or a different speed.

  When the sample S is cooled to room temperature, the optical sensor 7 automatically detects the reddish purple color of potassium permanganate in the sample S again, and whether or not an undecomposed sample remains in the sample S. Confirmation is performed. Note that this second color detection step may be omitted.

As the sample S in the sample container 10 evaporates during heating, potassium permanganate, sulfuric acid, etc. contained in the solution stick to the inner wall of the sample container 10. In particular, potassium permanganate adsorbs the mercury gas generated later and affects the measured value, so it must be removed. Therefore, after cooling to room temperature, the inner wall cleaning is started by spraying a reagent solution of hydroxylammonium chloride (HONH ₃ Cl), which is sent from the sample dispensing device 2, and cleaning is performed for a predetermined time. Potassium manganate is reduced. In this way, using the sample dispensing device 2, the deposits (sulfuric acid, potassium permanganate, etc.) adhering to the inner wall of the sample container 10 before the measurement of mercury gas in the sample are automatically washed.

A tin chloride (SnCl ₂ ) solution is added as a reducing agent to the sample S after the pretreatment by a reductive vaporization method to generate mercury gas. In this case, air is sent from the air pump 31 (FIG. 1) of the mercury detector 3 to the bubbler 51 (FIG. 1) above the sample container 10. The mercury gas generated by the sample pretreatment device 1 is introduced into the absorption cell 21 (FIG. 1) of the mercury detection device 3 and measured.

  As described above, according to the present invention, when the turntable 12 having the annular holding portion 122 is rotated, the entire annular holding portion 122 that holds the sample container 10 by radiant heat from the heater 13 in a non-contact manner. Is heated, the heating holding ring 122, which is a heating medium, does not have uneven heating, the samples S accommodated in the plurality of sample containers 10 are uniformly heated, and the temperature difference between the samples is extremely reduced. High-precision analysis can be performed. Since at least the upper parts of the plurality of sample containers 10 are exposed from the annular holding part 122, the sample containers 10 can easily dissipate heat, and the cooling time after heating can be shortened.

  In particular, in the reduced vaporization mercury measuring apparatus of this embodiment, since a part of more than half of the total height is exposed from the annular holding part 122 from the upper end of the sample container 10, the sample container 10 is more easily dissipated and the cooling time after heating is increased. It can be made shorter. Moreover, since the annular holding part 122 which is a heating medium and the sample container 10 held by the annular holding part 122 are simultaneously cooled by the blowing means 14, it is further efficiently cooled and the cooling time can be further shortened. In addition, since the circular concave portion 123 is formed on the inner diameter side of the annular holding portion 122, the sample container 10 can easily dissipate heat, and the cooling time can be further shortened. In the conventional reduced vaporized mercury measuring device, it took 1 hour to cool the sample S to 30 ° C. However, in the reduced vaporized mercury measuring device of this embodiment, it can be cooled to 30 ° C. in 35 minutes. .

  In the reduced vaporized mercury measuring device of this embodiment, the atomic absorption analyzer is described as the mercury detector 3. However, in the present invention, the mercury detector 3 may be an atomic fluorescence analyzer.

DESCRIPTION OF SYMBOLS 1 Sample pretreatment apparatus 2 Reagent dispensing apparatus 10 Sample container 12 Turntable 13 Heater 14 Blowing means 17 Temperature sensor 18 Temperature adjusting means 121 Axis 122 of vertical direction Annular holding part S Sample

Claims (3)

A reductive vaporization measuring device for measuring mercury in each sample by generating mercury gas by a reductive vaporization method after pretreatment of a plurality of samples by a sample pretreatment device,
The sample pretreatment device includes:
A reagent dispensing device for injecting a plurality of reagents into each of a plurality of sample containers containing samples;
A turntable that has a plurality of sample containers removably held in an annular arrangement around a vertical axis and has an annular holding part that exposes at least the upper part of the sample container, and is rotated around the axis.
A heater that is arranged to face a part of the lower surface of the annular holding part and heats the part of the annular holding part located immediately above, in a non-contact manner,
A temperature sensor for measuring the temperature of the annular holding part in a non-contact manner;
A reduced vaporized mercury measuring apparatus comprising temperature adjusting means for adjusting the temperature of the sample by controlling the amount of heat generated by the heater based on the temperature of the annular holding part measured by the temperature sensor. In the reduced vaporization mercury measuring apparatus according to claim 1,
The reduced vaporized mercury measuring device in which the annular holding part exposes 1/2 to 3/4 of the total height from the upper end of the sample container. In the reduced vaporization mercury measuring apparatus according to claim 1 or 2,
A reduced vaporized mercury measuring apparatus comprising a blowing means or an exhaust means for air-cooling the annular holder and the sample container from the side.

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