JP2004212075A - Morphological analytical sample pretreatment method and device by hydride introducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the whole processing, to reduce the load of an operator, to shorten a processing time, and to resultantly heighten measurement accuracy. <P>SOLUTION: NaBH<SB>4</SB>solution is supplied to the bottom part of a reaction vessel 2 by a pipe, and sample solution, hydrochloric acid and an additive are provided by a pipe from above the reaction vessel 2. Volatile hydrides generated in the reaction vessel 2 are taken out together with helium gas through a generated gas pipe 38, transferred to a cooling trap 72 through a steam trap 38 and a carbon dioxide trap 70, cooled and collected. All semimetal volatile hydrides are condensed and collected at a liquid nitrogen temperature in the cooling trap 72, and by raising the temperature, the collected hydrides are evaporated successively from a hydride having a low-boiling point morphology, desorbed and introduced to an analytical instrument, and then morphological analysis is performed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a method for analyzing an atomic absorption spectrometry (AA), an inductively coupled plasma analysis (ICP), an ICP-MS (inductively coupled plasma excitation-mass spectrometry), etc., in which a substance to be measured in a sample solution is vaporized into an analyzer. The present invention relates to a sample pretreatment method and an apparatus therefor.
[0002]
[Prior art]
As a pretreatment method for introducing a sample into these analytical instruments, a hydride generation method in which a semimetal element such as arsenic (As), antimony (Sb), or selenium (Se) is introduced into the analytical instruments as a volatile hydride. There is. The elements to be measured contained in the sample include various compounds with different forms such as chemical bonding state and oxidation state, but hydrides generated by the hydride generation method are all analyzed at the same time regardless of the form. Will be introduced.
[0003]
As another pretreatment method, in the case of a sample supplied in a gaseous state, the sample is cooled and concentrated with a refrigerant such as liquid nitrogen for the purpose of concentrating the sample, then the temperature is increased and desorbed, and the sample is led to an analytical instrument. There is an ultra-low temperature collection method.
[0004]
As still another pretreatment method, the compounds in each form mixed in the sample are once collected by cooling, and then the temperature is increased to sequentially desorb from the low-boiling form. There is a separation method for each form using a boiling point separation method leading to an analytical instrument.
Each of these sample pretreatment methods is an independent method, and is used individually.
[0005]
[Problems to be solved by the invention]
When trying to analyze metalloid elements such as As, Sb, and Se by form, the hydride generation method, the ultra-low temperature collection method, and the boiling point separation method are individually and manually performed. It is conceivable that a separated sample is prepared and introduced into an analytical instrument.
[0006]
However, since such independent methods are manually controlled, the entire processing becomes complicated. Further, since the processing becomes complicated, stable control becomes difficult, and as a result, there is a problem that the measurement accuracy is reduced.
[0007]
In addition, since independent control is required for each method, there is a problem that the processing time becomes long as a result.
Further, since individual processes are controlled manually, the burden on the operator is large.
[0008]
Thus, the present invention simplifies the entire pretreatment method for converting a substance to be measured that produces volatile hydrides into volatile hydrides and introducing the volatile hydrides into analytical instruments according to the form, thereby reducing the burden on the operator. It is an object of the present invention to provide a method capable of reducing the processing time, shortening the processing time, and consequently improving the measurement accuracy, and an apparatus used for the method.
[0009]
[Means for Solving the Problems]
The sample pretreatment method of the present invention is a method of converting a substance to be measured in a sample solution into a volatile hydride and supplying the volatile hydride to an analyzer. The method includes the following steps (A) in a reactor connected by piping. (D) is performed as a series of processes.
(A) weighing out a predetermined amount of a sample solution and introducing it into a reaction tank of the reaction apparatus;
(B) a hydrogenation step of reacting a sample solution with a reaction reagent for hydrogenation in the reaction tank to generate a volatile hydride of a substance to be measured;
(C) a collection step of guiding the hydride to a cooling trap for collection, and
(D) Form-specific separation step in which the hydride collected by raising the temperature of the cooling trap is sequentially desorbed from those having a low boiling point and guided to the analyzer.
[0010]
As described above, in the sample pretreatment method of the present invention, each step of sample introduction, hydride generation, ultra-low temperature collection, and boiling point separation is performed as a series of processes in a reactor connected by piping. In addition, the entire process is simplified, the burden on the operator is reduced, the processing time is shortened, and as a result, the measurement accuracy can be improved.
[0011]
The sample pretreatment apparatus of the present invention for realizing this sample pretreatment method includes a sample pipe to which a sample solution is supplied, a reagent pipe to which a reagent is supplied, a carrier gas pipe to which a carrier gas is supplied, and A reaction tank connected to at least a product gas pipe for extracting volatile hydrides together with the carrier gas; a sampling mechanism connected to a sample pipe to measure a predetermined amount of a sample solution and supply the sample solution to the reaction tank; and a reagent pipe. And a reagent supply mechanism for supplying a predetermined amount of reagent to the reaction vessel, a carrier gas supply mechanism for supplying a carrier gas to the reaction vessel connected to the carrier gas pipe, and a production gas pipe for connection with the carrier gas. The hydride that has been sent out is cooled and collected, and the temperature of the collected hydride is higher than the boiling point of the highest boiling form of the collected hydride from the cooling temperature for collection. And a cooling trap capable of changing the temperature between the stomach temperature.
[0012]
In the sample pretreatment device of the present invention, preferably, a pipe for supplying cleaning water is also connected to the reaction tank, and an openable / closable drainage mechanism is connected to the bottom of the reaction tank. Thus, when cleaning the reaction tank before and after each pretreatment operation, the reaction can be performed with the reaction layer connected to the pipe, and the burden of the cleaning operation is reduced.
[0013]
It is preferable that the cross section of the bottom of the reaction vessel is smaller than the cross section of the top. Thereby, even a small amount of the sample solution can be processed.
The reaction tank preferably has a stirring mechanism for stirring the solution inside. Thereby, reaction and washing can be promoted.
[0014]
Since volatile hydride is generated from the sample solution and moves upward, and is sent from above through the product gas pipe, the carrier gas outlet of the carrier gas pipe is used to facilitate the movement of such product hydride. Is preferably arranged at the bottom in the reaction tank.
[0015]
Since water vapor and carbon dioxide gas often interfere with the measurement of the hydride of the substance to be measured, one or both of a water vapor trap and a carbon dioxide trap are arranged between the reaction tank and the cooling trap in the product gas piping. Is preferred.
[0016]
The sample pretreatment device of the present invention preferably includes a control device that controls the sample pretreatment method of the present invention. The control device has one or both of a manual mode and an automatic mode as an operation mode.
[0017]
In the manual mode, a series of operations are controlled by an operation mode in which a message prompting an operation instruction is displayed for some operations, and the operation is performed after the instructions are input.
[0018]
In the auto mode, when the start of the operation is instructed, a series of operations is controlled by an operation mode in which the operation automatically proceeds based on the set timing.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows a pretreatment apparatus according to one embodiment.
Reference numeral 2 denotes a reaction tank whose shape is such that the cross-sectional area of the bottom is small, so that a small amount of sample solution can be processed. A drain port 4 is provided at the bottom of the reaction tank 2, and a drain pump 6 is connected to the drain port 4 so that the liquid in the reaction tank 2 is discharged to the drain by the operation of the drain pump 6. It has become. A drain mechanism that can be opened and closed by the drain port 4 and the drain pump 6 is configured.
[0020]
A stirrer 5 is placed at the bottom of the reaction tank 2. The stirrer 5 is rotated by a magnetic field from a magnetic drive device disposed below the reaction tank 2 and can stir the liquid in the reaction tank 2.
[0021]
At the bottom of the reaction tank 2 is NaBH which is a hydrogenation reagent for converting a substance to be measured into a hydride. _Four Is connected through an opening / closing valve 8. NaBH _Four NaBH by pump 10 _Four A solution 12 is supplied. Helium gas supplied from the helium cylinder 14 and maintained at a constant pressure by the regulator 16 _Four Opening and closing are controlled by being supplied by the injection valve 18.
[0022]
The upper part of the reaction tank 2 is sealed by a lid 20. The lid 20 is connected to a sample pipe 22 to which a sample solution is supplied, a hydrochloric acid pipe 24 to which hydrochloric acid is supplied, an additive pipe 26 to which an additive is supplied, and a cleaning liquid pipe 28 to which a cleaning liquid is supplied. I have. The outlets of these pipes 22, 24, 26, 28 are positioned at the upper part in the reaction tank 2.
[0023]
A syringe 40 and a sample loop 42 are provided as a sampling mechanism for collecting a sample solution and supplying the sample solution to the reaction tank 2. Reference numeral 44 denotes a syringe valve. The syringe 40 is connected to a common port of the syringe valve 44, and the sample loop 42 is connected to one port of the syringe valve 44. A pipe connected to distilled water 46 is connected to the other port of the syringe valve 44. Reference numeral 48 denotes a sample valve, the sample loop 42 is connected to a common port (COM) of the sample valve 48, and a normally open port (NO) of the sample valve 48 is connected to a sampling nozzle 50. The closed port (NC) is connected to a sample pipe 22 connected to the reaction tank 2.
[0024]
In order to dispense the sample solution by the nozzle 50, a plurality of sample containers 52 accommodating the sample solution and a cleaning port 54 used for cleaning the nozzle 50 are arranged. The operation of taking the nozzle 50 into and out of the sample container 52 and the washing port 54 can be performed manually, or can be performed automatically using an autosampler. The autosampler is used when operating in the auto mode.
[0025]
Hydrochloric acid 56 is connected to a hydrochloric acid pipe 24 connected to the reaction tank 2 so as to be supplied by a hydrochloric acid pump 58.
An additive 60 is connected to the additive pipe 26 so as to be supplied by an additive pump 62.
[0026]
The cleaning pipe 28 is connected to the cleaning pipe 28 so that cleaning water 64 is supplied by a cleaning pump 66.
A carrier gas supply pipe 30 for supplying a carrier gas is attached to the center of the lid 20 of the reaction tank 2, and the outlet of the carrier gas supply pipe 30 is positioned near the bottom of the reaction tank 2. Helium gas adjusted to a constant pressure from the helium cylinder 14 by the regulator 32 is supplied to the carrier gas supply pipe 30 through the opening / closing valve 34, the flow regulator 35 and the flow meter 36.
[0027]
In order to take out the volatile hydride generated in the reaction tank 2 together with the helium gas as the carrier gas, a production gas pipe 38 is also attached to the lid 20, and the gas inlet of the production gas pipe 38 is connected to the reaction vessel 2. It is positioned at the top inside.
[0028]
Four steam traps 68 arranged in series are connected to the generated gas pipe 38, and the steam trap 68 is cooled to −20 ° C. by the refrigerant 74 to condense water in the gas flowing through the generated gas pipe 38. To collect.
[0029]
A carbon dioxide gas trap 70 is connected downstream of the steam trap 68. The carbon dioxide gas trap 70 traps carbon dioxide gas by filling the inside with particulate NaOH. The carbon dioxide gas trap 70 can be omitted.
[0030]
Downstream of the carbon dioxide trap 70, a cooling trap 72 that can cool and collect hydride is connected. The cooling trap 72 is formed of a U-shaped tube, and is filled with quartz glass wool. The cooling trap 72 can be cooled to about -190 ° C. using the liquid nitrogen 76 as a refrigerant. By removing the U-shaped tube from the liquid nitrogen 76, the temperature of the cooling trap 72 can be returned to room temperature. The downstream of the cooling trap 72 is connected to an analytical instrument such as an atomic absorption spectrometer.
[0031]
In the cooling trap 72, all the volatile hydrides of the metalloid are condensed and collected at the liquid nitrogen temperature. By removing the U-tube from the liquid nitrogen 76, the temperature of the cooling trap 72 rises, and as the temperature rises, the collected hydride volatilizes and desorbs sequentially from those having a low boiling point. , Led to analytical instruments. This allows for morphological analysis.
[0032]
Next, the operation of this embodiment will be described based on the flowcharts of FIGS. 2 to 6 and the timing charts of FIGS. 7 to 12. In this embodiment, a message is displayed for a plurality of operations, and the operator instructs the operation by a key operation in response to the operation, and a manual mode in which a part of the operation is performed manually, and a key operation for starting the operation. In this case, there are provided two operation modes, ie, an automatic mode in which all subsequent operations are automatically advanced when the instruction is given, and any one of the operation modes can be selected from the menu screen. 2 to 4 and 7 to 9 show the operation in the manual mode, and FIGS. 5, 6 and 10 to 12 show the operation in the auto mode. 2 to 4 are a series of flowcharts, and FIGS. 5 and 6 are also a series of flowcharts. 7 to 9 are a series of timing charts, and FIGS. 10 to 12 are also a series of timing charts. In the timing charts, some of the joints in the drawings are partially overlapped.
[0033]
In the present invention, drying of the quartz glass wool filled in the U-shaped tube of the cooling trap 72, which is a hydride collecting part, is an important element, and helium gas as a carrier gas is always flowed before and during use. Condition to promote drying.
[0034]
When you turn on the power, a menu screen appears on the display. Therefore, the operator selects either the manual mode or the automatic mode.
Now, assuming that the manual mode has been selected, the operation in the manual mode will be described with reference to the flowcharts of FIGS. 2 to 5 and the timing charts of FIGS.
[0035]
Initialization is performed before sample pretreatment. The initialization is a process for filling a sample supply flow path with cleaning water, filling each reagent supply pipe with each reagent, washing the reaction tank 2 and preparing for a sample pretreatment operation. First, the initialization operation will be described.
[0036]
When the operator performs a key input to start the initialization operation, the syringe 40 is positioned at the upper limit position, the syringe unit is initialized (step 1), and the cooling trap 72 is moved to the upper limit position of the U-tube. It is set (step 2). It should be noted that the numbers entered in the flowchart are the numbers of the steps, and are described as “step ○” in the description of the embodiment.
[0037]
Subsequently, when the operator inputs the key "PRIME" by filling the water, the helium valve 34 is opened and the helium gas in the cylinder 14 is sent to the reaction tank 2 and flows from the generated gas pipe 38 through the cooling trap 72 (step 3). ).
[0038]
Subsequently, a message prompting to put the nozzle into the cleaning port is displayed (step 4). Therefore, in order to proceed to the next step, when the operator inputs “GO” by key operation, switching of the syringe valve 44 and the operation of the syringe 40 are repeated with the sample valve 48 connected to the nozzle side, and the distilled water 46 is discharged from the nozzle 50 to the cleaning port 54, and the piping of the sample loop 42 and the nozzle 50 is filled with water (Step 5).
[0039]
When filling is completed, a message is displayed prompting the user to remove the nozzle from the washing port (step 6). In order to proceed to the next step, when the operator inputs "GO" by key operation, the drainage pump 6 starts operating (step 7), and the sample valve 48 is switched to the sample pipe 22 (reaction tank side). By switching the syringe valve 44 and the operation of the syringe 40, distilled water is discharged to the reaction tank 2 via the pipe 22, and the operation of discharging from the drain pump 6 is repeated a predetermined number of times. (Step 8).
[0040]
By operating the hydrochloric acid pump 58 for a predetermined time in parallel with the filling operation of the pipe 22, hydrochloric acid is discharged to the reaction tank 2 via the pipe 24, and the pipe 24 is filled with hydrochloric acid (step 9). Subsequently, when the additive pump 62 operates for a predetermined time, the additive is discharged to the reaction tank 2 via the pipe 26, and the pipe 26 is filled with the additive (step 10). Then NaBH _Four The pump 10 operates for a predetermined time, and then NaBH _Four When the injection valve 18 is repeatedly turned on and off, the valve 8 is turned on and off repeatedly, and the NaBH _Four NaBH from piping _Four Is discharged into the reaction tank 2, whereby NaBH _Four NaBH _Four (Step 11).
[0041]
After a predetermined time (for example, 3 seconds), the drain pump 6 stops operating (step 12), the cleaning pump 66 operates to supply cleaning water to the reaction tank 2, and the stirrer 5 is driven by an external magnetic drive. When driven and rotated by the apparatus, the stirring operation is performed to clean the inside of the reaction tank 2 (steps 13 and 14). Thereafter, the drainage pump 6 is operated to discharge the cleaning liquid, and the stirring operation is stopped to complete the cleaning of the inside of the reaction tank 2 (step 15). Thereafter, the carrier gas is continuously released from the end of the carrier gas supply pipe 30 for a predetermined time, so that the inside of the reaction tank 2 is dried, and at the same time, the cooling trap 72 is also dried from the generated gas pipe 38 (Step 16), and the initialization is completed. I do. A message "WAITING START" is displayed to prompt the user to instruct the start of the preprocessing operation (step 17).
[0042]
After that, the sample pre-processing operation is started. When the operator inputs "START" by a key operation, the helium valve 34 is opened and the carrier gas passes through the reaction tank 2 from the generated gas pipe 38 to the U-tube of the cooling trap 72, and is dried for a predetermined time. Is performed (step 18). Thereafter, the U-shaped tube of the cooling trap 72 is immersed in liquid nitrogen 76 (Step 19), and cooled for a predetermined time (Step 20). The pump 58 operates for a predetermined time, and a predetermined amount of hydrochloric acid is supplied to the reaction tank 2 (steps 21 and 22). Subsequently, the additive pump 62 operates for a predetermined time, and a predetermined amount of the additive is added to the reaction tank 2 (step 23).
[0043]
Here, a message "prompt for sampling" is displayed (step 24), and the operator manually immerses the nozzle 52 in the sample solution (step 25) and inputs "GO" by key operation. The sample solution descends and the sample solution is sucked (step 26). Next, "NOZZLE UP" is displayed to prompt the user to raise the nozzle (step 27). The operator manually removes the nozzle 50 from the sample solution (step 28) and inputs "GO" by key operation. The sample solution sucked into the nozzle 54 by moving down 40 is drawn into the sample loop 42 (step 29). Next, the sample valve 48 is switched to the reaction tank side, the syringe 40 is raised, and the sample solution in the sample loop 42 is injected into the reaction tank 2 (steps 30 and 31).
[0044]
Subsequently, in order to inject the hydrogenation reagent into the reaction tank 2, NaBH _Four The pump 10 is operated for a predetermined time (step 32), and then NaBH _Four A predetermined amount of NaBH is passed through the valve 8 by repeatedly turning on and off the injection valve 18 a set number of times. _Four The solution is injected into the reaction tank 2 (Step 33). Thereby, the sample solution and the NaBH _Four Reacts to generate hydride, which is led to the cooling trap 72 via the generated gas pipe 38 and collected.
[0045]
After a predetermined period of time for completing the collection of hydrides (step 34), the measuring instrument performs a zero level adjustment (auto zero), and then displays a message prompting the start of the measurement. When "GO" is input, a measurement start signal is output (step 35). Here, instead of waiting for the operator to input “GO” by key operation, after performing the zero level adjustment (auto zero), the process may proceed to step 35 for immediately outputting the measurement start signal.
[0046]
When the measurement start signal is output, the U-shaped tube of the cooling trap 72 is pulled up from the liquid nitrogen (step 36), and the hydride collected in the cooling trap 72 is volatilized sequentially from the one having a low boiling point. The desorption is started, the boiling point is separated, hydrides are sequentially introduced into the measuring instrument, and the measurement is performed for a predetermined time (step 37).
[0047]
Thereafter, a message prompting a drainage operation is displayed (step 38), and when the operator inputs "GO" by key operation, the drainage pump 6 is operated to discharge the reaction solution in the reaction tank 2 (step 39). ).
[0048]
At this time, a message prompting nozzle cleaning is displayed (step 40). After the operator manually inserts the nozzle 50 into the cleaning port 54 (step 41), and inputs "GO" by key operation, the syringe valve 44 is displayed. Is switched and the operation of the syringe 40 is performed to clean the nozzle 50 (step 42).
[0049]
Thereafter, a message prompting to lift the nozzle 50 from the cleaning port 54 is displayed (step 43). When the operator manually lifts the nozzle 50 from the cleaning port 54 and inputs "GO" by key operation (step 44), The syringe 40 is lowered to suck air into the nozzle 50, and an air gap is created (step 45).
[0050]
Next, the sample valve 48 is switched to the reaction tank side, the drainage pump 6 starts operating, and the sample path including the sample loop 42 and the sample pipe 22 is washed by switching the syringe valve 44 and operating the syringe 40. (Steps 46 and 47). After a predetermined time, the washing operation is stopped, the sample valve 48 is switched to the nozzle side, and the operation of the drainage pump 6 is stopped (steps 48 and 49).
[0051]
Subsequently, the cleaning pump 66 operates for a predetermined time to supply cleaning water to the reaction tank 2 (step 50). During this time, the stirrer 5 continues stirring. After the supply of the washing water is stopped, after stirring for a predetermined time, the drainage pump 6 is operated to discharge the washing liquid in the reaction tank 2 and the stirrer 5 is stirred. The operation stops (steps 51 and 52).
Thereafter, the helium gas valve 34 is opened for a certain period of time, and the operation for one sample solution ends (step 53). The same operation is repeated for the next sample solution.
[0052]
Next, the operation in the auto mode will be described. In the manual mode, a message is displayed on the display, and the operator performs work or inputs an instruction by key input according to the message.In the auto mode, a key input for starting the initial initialization operation and a water input are performed. The operator performs the key input of “PRIME” for instructing the start of the clogging operation and the key input of “START” for instructing the start of the pre-processing operation, but the subsequent operations are performed by an automatic sample changer (ASC). The operation is automatically processed while controlling. In the auto mode, an auto sampler is used as a mechanism for supplying the sample solution and a mechanism for cleaning the sampling nozzle.
5 and 6 show the operation, and FIGS. 10 to 12 are timing charts thereof.
[0053]
When the operator performs an input for starting the initialization operation, the syringe unit in which the syringe 40 is positioned at an intermediate position between the upper limit and the lower limit is initialized (step 1), and the position of the U-tube is changed. The upper limit is set (step 2).
[0054]
Subsequently, when the operator inputs a key "PRIME" for instructing water filling, the initialization operation up to step 15 is performed. The contents of the operation up to this point are the same as those in the manual mode. This processing device controls the autosampler and automatically advances the operation without waiting for a key input by the user. “PSD RD” in FIG. 8 is a command transmitted from the processing apparatus to the ASC, and means an operation of moving the arm to the cleaning port (the position of the RD) and lowering the nozzle. By the transmission of the command, the operation of the ASC enters a state where the nozzle position is inserted into the cleaning port, and the processing apparatus performs the cleaning operation of the nozzle.
Immediately after the end of the cleaning operation, a "NU" command is transmitted to the ASC, and the ASC is in a state where the nozzle is pulled up from the cleaning port. Thereafter, the processing apparatus performs an operation of creating an air gap, and performs the filling operation of the pump path and the filling operation of the distilled water in the sample injection path in parallel as in the manual mode.
When the drainage after the cleaning operation is completed, a command of “PSD WT” is transmitted to the ASC, and the ASC moves the nozzle position to the standby position (a position slightly shifted from above the cleaning port). Thereafter, the operation of drying the path is the same as in the manual mode.
[0055]
After that, the sample pre-processing operation is started. When the operator inputs the number of samples and the sample conditions, and inputs "START" by key operation, the helium valve 34 is opened and the carrier gas passes through the reaction tank 2 from the generated gas pipe 38 through the U-shaped pipe of the cooling trap 72. The drying of the U-shaped tube is performed for a predetermined time, during which a message indicating that the drying is in progress is displayed (steps 16 and 17). Thereafter, the U-shaped tube of the cooling trap 72 is immersed in the liquid nitrogen 76, and a message indicating that cooling is in progress is displayed (steps 18 and 19). After cooling for a predetermined time (step 20), the stirrer 2 is rotated in the reaction tank 2 to start stirring operation, the hydrochloric acid pump 58 is operated for a predetermined time, a predetermined amount of hydrochloric acid is supplied to the reaction tank, and sampling is performed. Is displayed (steps 21, 22, 23). Subsequently, the additive pump 62 operates for a predetermined time, and a predetermined amount of the additive is added to the reaction tank 2 (Step 24).
[0056]
Next, the nozzle 52 is immersed in the sample solution by ASC (step 25), and after a predetermined time, the syringe 40 is lowered by a predetermined amount and the sample solution is sucked. Next, a command "NU" for raising the nozzle is transmitted, the nozzle 50 is pulled up from the sample solution by the ASC, the syringe 40 is lowered, and the sample solution sucked into the nozzle 54 is drawn into the sample loop 42 (step 26). Next, the sample valve 48 is switched to the reaction tank side (step 27), the syringe 40 is raised, and the sample solution in the sample loop 42 is injected into the reaction tank 2 (step 28).
[0057]
Subsequently, in order to inject the hydrogenation reagent into the reaction tank 2, NaBH _Four The pump 10 is operated for a predetermined time (step 29), and then NaBH _Four A predetermined amount of NaBH is passed through the valve 8 by repeatedly turning on and off the injection valve 18 a set number of times. _Four The solution is injected into the reaction tank 2 (Step 30). Thereby, the sample solution and the NaBH _Four Reacts to generate hydride, which is led to the cooling trap 72 via the generated gas pipe 38 and collected.
[0058]
After a predetermined time period for completing the collection of hydrides (steps 31 and 32), the measuring instrument performs a zero level adjustment (auto zero), outputs a measurement start signal, and outputs a message indicating that the measurement is in progress. Is displayed (steps 33 and 34). When the measurement start signal is output, the U-shaped tube of the cooling trap 72 is pulled up from liquid nitrogen (step 35), and the hydride collected in the cooling trap 72 volatilizes sequentially from the one having a low boiling point. The dehydration is started, the boiling point is separated, hydrides are sequentially introduced into the measuring instrument, and the measurement is performed for a predetermined time (step 36).
[0059]
Thereafter, the drainage pump 6 operates to discharge the reaction solution in the reaction tank 2 (step 37).
In parallel with this, a message indicating that the cleaning operation is being performed is displayed (step 38), and after the nozzle 50 is inserted into the cleaning port 54 by the controller (step 39), the switching of the syringe valve 44 and the operation of the syringe 40 are performed. Is performed to clean the nozzle 50 (step 40).
[0060]
Thereafter, the nozzle 50 is pulled up from the cleaning port 54 by ASC (step 41), and the syringe 40 is lowered to suck air into the nozzle 50 to form an air gap (step 42).
[0061]
Thereafter, the sample valve 48 is switched to the reaction tank side, the drainage pump 6 starts operating, and the sample path including the sample loop 42 and the sample pipe 22 is washed by switching the syringe valve 44 and operating the syringe 40. (Steps 43 and 44). After a predetermined time, the cleaning operation is stopped, the sample valve 48 is switched to the nozzle side, and the operation of the drainage pump 6 is stopped (steps 45 and 46).
[0062]
Subsequently, the cleaning pump 66 operates for a predetermined time to supply cleaning water to the reaction tank 2 (step 47). During this time, the stirrer 5 continues stirring. After the supply of the washing water is stopped, after stirring for a predetermined time, the drainage pump 6 is operated to discharge the washing liquid in the reaction tank 2 and the stirrer 5 is stirred. The operation stops (steps 48 and 49).
[0063]
After a predetermined time, the helium valve 34 is opened for a certain time, and the operation for one sample solution is completed (step 50).
The count value of the number of samples is reduced by 1 (step 51), and the same operation is repeated until the number of samples set before the start becomes zero.
[0064]
【The invention's effect】
According to the present invention, in the reactor connected by piping, each step of sample introduction to hydride generation, ultra-low temperature collection, and boiling point separation is performed as a series of processing, so that control of the processing is performed here. The processing control can be simplified by integrating the processing into a series of processing, and labor saving can be realized by integrating the processing into one apparatus, thereby shortening the processing time and improving the measurement accuracy.
As a result, conventionally, a single process from sampling to the end of the process required a time of several tens of minutes due to the division of the processing procedure, but in the present invention, a single process can be performed in about 5 minutes. Was.
In addition, the accuracy of the measurement was improved, and the reproducibility of the repeated measurement by the atomic absorption method was improved from about 20% in the past to 10% or less.
In the present invention, the amount of work of the processing operator has conventionally been all manual work, but in the present invention, it can be simplified to only sample preparation and device operation (key input).
[Brief description of the drawings]
FIG. 1 is a flow diagram illustrating a pretreatment device according to an embodiment.
FIG. 2 is a flowchart showing a part before an operation in a manual mode of the embodiment.
FIG. 3 is a flowchart showing an intermediate part of the operation in the manual mode of the embodiment.
FIG. 4 is a flowchart showing a part after the operation in the manual mode of the embodiment.
FIG. 5 is a flowchart showing the first half of the operation in the auto mode of the embodiment.
FIG. 6 is a flowchart showing the latter half of the operation in the auto mode of the embodiment.
FIG. 7 is a timing chart showing a part before the operation in the manual mode of the embodiment.
FIG. 8 is a timing chart showing an intermediate portion of the operation in the manual mode.
FIG. 9 is a timing chart showing a part after the operation in the manual mode.
FIG. 10 is a timing chart showing a part before the operation in the auto mode of the embodiment.
FIG. 11 is a timing chart showing an intermediate portion of the operation in the auto mode.
FIG. 12 is a timing chart showing a part after the operation in the auto mode.
[Explanation of symbols]
2 Reaction tank
4 drainage outlet
5 stirrer
6 Drainage pump
8 Open / close valve
10 NaBH _Four pump
12 NaBH _Four solution
18 NaBH _Four Injection valve
30 Carrier gas supply pipe
38 Generated gas piping
40 syringe
42 sample loop
44 syringe valve
48 sample valve
50 nozzles
58 hydrochloric acid pump
62 additive pump
66 Cleaning pump
68 steam trap
70 Carbon dioxide trap
72 Cooling trap

Claims (12)

The following steps (A) to (D) are performed as a series of processes in a reactor connected by piping in order to convert a substance to be measured in a sample solution into a volatile hydride and supply the volatile hydride to an analyzer. A sample pretreatment method, characterized in that:
(A) weighing out a predetermined amount of a sample solution and introducing it into a reaction tank of the reaction apparatus;
(B) a hydrogenation step of reacting a sample solution with a reaction reagent for hydrogenation in the reaction tank to generate a volatile hydride of a substance to be measured;
(C) a collecting step of guiding the hydride to a cooling trap to collect the hydride, and (D) sequentially increasing the temperature of the cooling trap so that the collected hydride is in a form having a low boiling point. A separation step for each form that is desorbed and led to an analyzer. Reaction in which at least a sample pipe to which a sample solution is supplied, a reagent pipe to which a reagent is supplied, a carrier gas pipe to which a carrier gas is supplied, and a generated gas pipe for taking out the generated volatile hydride together with the carrier gas are connected. Tank and
A sampling mechanism connected to the sample pipe, for weighing a predetermined amount of the sample solution and supplying the sample solution to the reaction tank;
A reagent supply mechanism connected to the reagent pipe, for supplying a predetermined amount of reagent to the reaction tank,
A carrier gas supply mechanism connected to the carrier gas pipe and supplying a carrier gas to the reaction vessel;
The hydride that is connected to the generated gas pipe and cooled and collected together with the hydride that has been sent out together with the carrier gas has a temperature higher than the boiling point of the highest boiling form of the collected hydride from the cooling temperature for collection. A sample pretreatment device, comprising: a cooling trap capable of changing a temperature between high temperatures. 3. The sample pretreatment device according to claim 2, wherein a pipe for supplying washing water is also connected to the reaction tank, and an openable / closable drainage mechanism is connected to a bottom of the reaction tank. 4. The sample pretreatment device according to claim 2, wherein a cross-sectional area of a bottom portion of the reaction vessel is smaller than a cross-sectional area of a top portion. 5. The sample pretreatment device according to any one of claims 2 to 4, wherein the reaction tank includes a stirring mechanism that stirs an internal solution. The sample pretreatment device according to any one of claims 2 to 5, wherein a carrier gas outlet of the carrier gas pipe is disposed at a bottom in the reaction tank. The sample pretreatment device according to claim 2, wherein a steam trap is disposed between the reaction tank and the cooling trap in the generated gas pipe. The sample pretreatment device according to any one of claims 2 to 7, wherein a carbon dioxide gas trap is disposed between the reaction tank and the cooling trap in the generated gas pipe. 9. The sample pretreatment device according to claim 2, further comprising a control device for performing the following steps (A) to (D) as a series of processes.
(A) weighing out a predetermined amount of a sample solution and introducing it into a reaction tank of the reaction apparatus;
(B) a hydrogenation step of reacting a sample solution with a reaction reagent for hydrogenation in the reaction tank to generate a volatile hydride of a substance to be measured;
(C) a collecting step of guiding the hydride to a cooling trap to collect the hydride, and (D) sequentially increasing the temperature of the cooling trap so that the collected hydride is in a form having a low boiling point. A separation step for each form that is desorbed and led to an analyzer. 10. The control device according to claim 9, wherein the control device displays a message prompting an operation instruction for some operations, and controls a series of operations in a manual mode in which the operations are performed after the instructions are input. Sample preparation equipment. 10. The sample pretreatment according to claim 9, wherein when the start of the operation is instructed, the control device controls a series of operations in an auto mode in which the operation automatically proceeds based on a set timing. apparatus. The control device displays a message prompting an operation instruction for some operations, a manual mode in which the operation is performed after waiting for the input of the instruction, and a start mode of the operation when the operation is instructed. The sample pretreatment according to claim 9, further comprising two operation modes of an automatic mode for automatically performing an operation based on the set timing, wherein a series of operations can be controlled by any of the operation modes. apparatus.

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