JP3035460B2 - Control device for autosampler and control method therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for an autosampler and a control method therefor, and more particularly to an improvement in operation control of the autosampler in response to a change in an analysis sequence.

[0002]

2. Description of the Related Art Many analyzers such as a pump, a column, a column oven, and a detector are configured as a system in an analyzer such as a high performance liquid chromatograph. Recently, analyzers equipped with a system controller (system controller) for controlling the operation set values (analysis conditions) of the respective devices in a computer in a comprehensive manner by an apparatus control program (system program) are widely used.

When a large number of samples are measured, an autosampler is used as a sample injector of the analyzer, and continuous measurement by automatic injection can be performed by controlling the injection conditions by an automatic sample injection program. Become. Although the standard value of the basic operation is set in the system controller in advance in the automatic sample injection program, an autosampler user's program for setting a desired operation by an operator can be set in the system controller.

Furthermore, the sample to be injected by the autosampler is used under the same conditions (injection amount, injection frequency, measurement conditions,
Automatic measurement of all samples is possible by the analysis procedure setting program (analysis sequence) that specifies each successive sample to be measured in (measurement time, etc.) and makes the measurement for each sample (this is called a step). Becomes

That is, in the analysis sequence, as shown in Table 1 below, an analysis procedure is programmed in the order in which a series of samples are designated, and sample measurement is sequentially performed according to the conditions set in each step.

[Table 1] Step Measurement start Measurement end Number of injections Injection amount Measurement time Measurement condition number Sample number Sample number (μl) (min) File number ──────────────────── {11-10 11 10 20 12 11 11-20 11 10 10 23 33 35 40 25 15 53} ──────────────────────────

Here, after the automatic continuous measurement based on the analysis sequence is started, it may be necessary to add or reduce a sample, or the analysis time initially set may be long or short. is there. For this reason, the content of the analysis sequence can be edited even during the measurement, and in such a case, the condition set in each step is changed to an appropriate value. However, the operation according to the changed condition is started from the time when the content is instructed after the editing is completed. In addition, the conventional system controller operates the autosampler to perform suction injection according to the condition before the change even during editing of the analysis sequence, and continues the continuous measurement.

On the other hand, the operation of the autosampler requires several minutes from the start of the suction operation until the sample can be injected into the column. The time corresponding to the required time is called a delay time. In the automatic continuous measurement based on the analysis sequence, it is desirable that the injection for the next sample measurement is performed immediately after the end of the analysis of a certain sample because the measurement time can be reduced. Therefore, in order to perform such continuous continuous measurement, assuming that the sample injection time is set to 0 as shown in FIG. 5, the sample aspirating operation takes the delay time from the 0 time to obtain (0- (Delay time).

[0008]

However, in the conventional operation control of the autosampler by the system controller, it is difficult to change the condition in the above-described analysis sequence in the currently executed step, and in particular, it is difficult to change the condition. It was extremely difficult when the measurement was taken in. That is, even if the editing of the analysis sequence is started as described above, the operation of the autosampler is continued, and the operation is performed based on the set value before the editing until the editing of the analysis sequence is instructed.

Thus, for example, while measuring sample number 5 in Table 1, the editing is started and the sample number in step 1 is changed to 1-5, and the next injection is performed in step 2 instead of sample number 6. Attempt to number 11. At this time, if the delay time of the next sample arrives during the editing, the autosampler starts the sample suction operation of the sample number 6 which is the next sample before the editing. For this reason, although the sample number 6 is deleted in the analysis sequence, the next injection is actually performed on the sample number 6, and the obtained measurement data and the specified sample number become inconsistent. It will be lost. In order to avoid such danger, the conventional system controller has no choice but to make it impossible to change the condition of the measurement step being executed, and there is a problem that the range of the change is limited.

[0010] Even in the conventional system controller, if the system is stopped, reset, the conditions are changed, and the analysis is newly performed, it is naturally possible to change the conditions of the steps being executed. However, this method is very time-consuming and also causes a problem that it takes a long time to stabilize the baseline again since the liquid supply is stopped by stopping the system.
Further, even if the condition change in the analysis sequence is enabled for the next step that is currently being executed, the same problem as in the case where the condition of the above-described step being executed is changed may occur depending on the timing of the condition change.

That is, for example, it is assumed that the editing of the analysis sequence is started while the sample number 10 in Table 1 is being executed, and the sample number in step 2 is changed to 21-30. At this time, if the delay time of the next sample arrives during the editing, the autosampler continues to operate according to the conditions set in step 2 before the editing, and starts the sample suction operation of sample number 11. . Regarding the number of injections, the injection amount, and the like, if the suction operation of the next sample is started before the editing is confirmed, the operation values will be those before editing.

As described above, even in the next step during execution, depending on the timing of the change, the changed condition may not be reflected in the operation of the system. Therefore, in order to reduce such a risk, the conventional system controller does not incorporate a delay time at the transition of each step, and as shown in FIG. A method of starting the sample suction operation has been adopted. For this reason, the injection interval is not constant between the step change and the other steps, and there has been a problem that in the case of gradient analysis or the like, the deviation of the analysis interval lowers the reproducibility. Further, when a large number of steps are set, if the delay time cannot be taken in at each step change, a considerable loss occurs in the entire analysis time.

As described above, in the operation control of the autosampler by the conventional system controller, it is difficult to change the conditions of the currently executing step and the next step. There has been a problem that the risk that the actual operation differs from the change intended by the operator or that the operation of the auto-rampler and the operation of the system cannot be consistent is extremely high. The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to set an injection operation incorporating a delay time in each sample including a step change, and to set each condition in an analysis sequence. Is to provide a control device and a control method of an autosampler that can change all steps including the step currently being executed.

[0014]

According to the present invention, there is provided a control apparatus for an autosampler, comprising: an analysis procedure setting means; an input means; a system control means; an editing detection means; The control device includes a detection unit, a suction operation control unit, a next sample determination unit, and a time management control unit.

The analysis procedure setting means sets the conditions relating to the measurement and analysis of each sample for each step in which the conditions are combined into a sample group having the same condition, and the set contents can be edited at all times.

The input means inputs the setting and editing contents in the analysis procedure setting means. The system control means
The operation of each measurement / analysis instrument is controlled in accordance with the conditions set and edited by the analysis procedure setting means. The editing detecting means detects the start and end of editing of the setting contents in the analysis procedure setting means.

The autosampler operation detecting means detects an operation state of the autosampler. The suction operation control means controls the stop and start of the suction operation of the autosampler based on each detection signal from the edit detection means and the autosampler operation detection means. The next sample determination means determines whether the next measurement sample instructed by the system control means at the end of editing is the same as the next injection sample detected by the autosampler operation detection means.

The time management control means, based on detection signals from the edit detection means and the autosampler operation detection means,
It manages and controls the time progress and stop in the system control means. The method for controlling an autosampler according to the present invention includes an input step, an analysis procedure setting step, a system control step, an edit detection step, an autosampler operation detection step, a suction operation control step, and a next sample determination step. And a time management control step.

In the input step, conditions relating to measurement and analysis of each sample are input for each step in which the conditions are combined into a sample group. In the analysis procedure setting step, the conditions are set and edited according to the input contents in the input step. The system control step controls the operation of each measurement / analysis instrument according to the conditions set and edited in the analysis procedure setting step. The editing detection step detects the start and end of editing of the setting conditions in the analysis procedure setting step.

The autosampler operation detecting step detects an operation state of the autosampler. The suction operation control step controls the stop and start of the suction operation of the autosampler in accordance with the operation state detected in the autosampler operation detection step when the edit start or the edit end is detected in the edit detection step. The next sample determination step determines whether the next measurement sample instructed to be measured in the system control step is the same as the next injection sample detected in the autosampler operation detection step at the time of completion of editing in the editing detection step. The time management control step manages and controls the time progress and stop in the system control step based on the edit start or edit end signal detected in the edit detection step and the operation signal detected in the autosampler operation detection step.

[0021]

The control apparatus and the control method of the autosampler according to the present invention first specify a series of consecutive sample groups to be measured and analyzed under the same conditions together with the conditions before starting the measurement, and further specify the sample groups in the measurement order. The arranged analysis procedures are input and set from the input means to the analysis procedure setting means. Then, according to the conditions of the set analysis procedure, each measurement / analysis device is controlled by the system control means, and the measurement / analysis of the sample is sequentially performed.

Next, if it is desired to change the set analysis procedure conditions after the start of the measurement, the conditions are edited and set again in the analysis procedure setting means from the input means. here,
When editing is performed in the analysis procedure setting means,
The start or end is detected by the edit detection means. When the editing detection means detects the start or end of the editing, the signal is input to the suction operation control means to control the suction operation of the autosampler. That is, when the editing start signal is input, the suction start operation of the autosampler is locked so that the suction of a new next sample is not started, and when the editing end signal is input, the lock of the autosampler is unlocked. , So that suction can be started.

On the other hand, the operation state of the autosampler is detected by the autosampler operation detection means, and the detection signal is also input to the suction operation control means. When the editing start signal is input while the autosampler is in the operating state before the injection after the start of the suction, after only the suction operation is terminated (the sample is held in a loop),
Control is performed so that the operation of the autosampler is stopped until the editing end signal is input. Further, when the autosampler has completed only the suction operation, a signal indicating which sample has been suctioned is input from the autosampler operation detection means to the next sample determination means when the measurement analysis is restarted by the end of editing. . Further, the signal of the next measurement sample instructed to be measured by the system control means according to the newly set condition is also input to the next sample determination means, and it is determined whether the next measurement sample is the same as the aspirated sample. .

The result of this determination is input to the system control means, and if the values are the same, the operation of the autosampler is controlled so as to inject the sucked sample. The sampler is discarded, and the autosampler is controlled so as to start the suction operation of the next measurement sample. Further, a detection signal of the start or end of editing and a detection signal of the operation of the autosampler are inputted to the time management control means, and the time progress and stop of the analysis time and the delay time are managed and controlled based on the detection signals. That is, when the end time of the analysis time arrives between the editing start and the end, the progress of the analysis time is stopped. Then, when the editing is completed, the autosampler starts the injection, and at the same time, the progress of the analysis time is resumed. The autosampler suction start time (analysis time end time-
Even if the delay time arrives, the capture of the delay time remains stopped, and the delay time starts simultaneously with the end of the editing.

As described above, the system control means operates the respective devices in accordance with the conditions newly edited and set by the analysis procedure setting means based on the input signals from the next sample determination means and the time management control means. Control.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an analyzer using a system controller as an autosampler control device according to one embodiment of the present invention. In the figure, a measuring device 10 constituted by each measuring device,
A system controller 14 is connected to an autosampler 12 as a sample injector.

The system controller 14 includes an input unit 16, a measurement condition setting unit 18, and an analysis procedure setting unit 2.
0, system control means 22, edit detection means 24, suction operation control means 26, next sample determination means 28, time management control means 30, and autosampler operation detection means 32. The input means 16 is connected to the measurement condition setting means 18 and the analysis procedure setting means 20. Further, the measurement condition setting means 18 and the analysis procedure setting means 20 are connected to a system control means 22, and a next sample determination means 28 and a time management control means 30 are connected to the system control means 22.

The analysis procedure setting means 20 is also connected to an editing detection means 24, which is connected to a next sample discriminating means 28, a time management control means 30, and a suction operation control means 26. ing. Further, an automatic sampler operation detection means 32 is connected to the suction operation control means 26, the next sample determination means 28, and the time management control means 30. On the other hand, the autosampler 12 includes a system control unit 22 and a suction operation control unit 2.
6 and the autosampler operation detecting means 32 are connected, and the measuring apparatus 10 is connected to the system control means 22.

The above is the schematic configuration of the system controller according to the present embodiment. Next, a specific operation will be described. First, the measurement condition setting unit 1 is input from the input unit 16.
In 8, the measurement conditions (system programs) of each device in the measurement apparatus 10 are input and set for each required file type. Further, the analysis procedure setting means 2 is input from the input means 16.
To 0, all conditions including the measurement conditions (injection amount, number of injections, measurement time, etc.) are designated by a step number for each of a series of consecutively measured samples, and an analysis sequence in which the steps are continued is designated. Set.

Then, according to the set analysis sequence, the measurement analysis is performed while the condition control relating to the measurement analysis is performed by the system control means 22.
During the measurement analysis, the continuous analysis monitor screen shown in FIG. 2 is displayed on the output means 34 connected to the system control means 22, so that the operating state of the system can be constantly checked.

Next, when it is desired to change the contents of the analysis procedure set at the start of the measurement in the middle of the measurement, by selecting "F1" shown in the lower part of FIG. 2, the analysis sequence screen shown in FIG. 3 is displayed. It is displayed on the output means 34. Further, by selecting "0: edit" shown in FIG. 3, a cursor appears on the analysis sequence screen as shown in FIG. 4, and the contents can be edited. Then, by selecting "1: fixed" shown in FIG. 4 after the editing is completed, the edited content is stored in the system control means 22, and the system is controlled in accordance with the edited content.

Here, in the conventional system controller, as described above, there is a problem in changing the contents of the currently executed and next steps. That is, conventionally, until the editing of the analysis sequence is determined, the autosampler continues to operate according to the conditions before the editing, and the measurement is sequentially continued. For this reason, the edited contents are not reflected in the operation of the system until the editing is confirmed, and even if the edited contents and the next step are edited during which there is a possibility that the edited contents and the operation of the system may overlap with each other, the operator's intention is changed. In some cases, the change differs from the actual operation.

Therefore, in the present embodiment, the conventional problems are solved by providing the edit detecting means 24, the suction operation control means 26, the next sample discriminating means 28, the time management control means 30, and the autosampler operation detecting means 32. This has been fixed, and the current step or the next step can be edited. That is, the system controller 14 operates as follows from the start of editing (when "0: edit" is selected) to the end of editing (when "1: fixed" is selected) in the analysis procedure setting means 20. . First, the editing start is detected by the edit detecting means 24, and the detection signal is output to the suction operation control means 26. Then, when the detection signal is input, the suction operation control means 26 prevents the autosampler 12 from starting a new sample suction operation even if the next suction start time (analysis time end time-delay time) arrives. Lock control. During the editing of the analysis sequence, a message indicating the locked state of the autosampler is displayed at the bottom of the screen as shown in FIG. 4 to notify the operator.

On the other hand, the sample whose suction operation has already started at the start of editing continues the measurement and analysis in accordance with the progress of the analysis time in the time management control means 30, but when the analysis time ends, the time management control starts. In the means 30, the progress of the analysis time is stopped. Further, when the editing is started before the injection after the start of the sample suction operation and the autosampler 12 is locked, only the suction operation of the sample is continued, and the sample is kept in a loop while waiting. .

Next, at the end of the editing of the analysis sequence, the system controller 14 operates as follows. The end of the editing is detected by the editing detecting means 24, and the detection signal is output to the suction operation control means 26. When the detection signal is input, the suction operation control means 26 releases the lock control of the suction start operation. If the lock release time is before the next suction start time, the analysis time continues to advance, and after the suction start time, the suction operation of the autosampler is started according to the newly edited and set condition. .

If the lock release time has passed the next suction start time, the autosampler immediately starts the suction operation of the next sample according to the newly edited and set conditions, and performs the analysis time currently in progress. At the end point, inject the sample. However, at the end of the analysis time, if the operation detected by the autosampler operation detection means 32 is still in the middle of suction, the progress of the analysis time in the time management control means 30 is stopped, and the analysis is completed at the time of completion of suction. The sample is injected at the same time as the time progress is resumed. If the analysis time has already ended and the progress has been stopped at the time of unlocking, the autosampler immediately starts aspirating the sample. Then, when the completion of the suction is detected by the autosampler operation detecting means 32, the progress of the analysis time in the time management control means 30 is resumed, and at the same time, the sample is injected.

When the editing is started during the sampling of the delay time, the sample is determined by the next sample determining means 28, and then the sample is injected based on the determination result. That is, the sample number sucked (or sucked) is output from the autosampler operation detecting means 32 to the next sample determining means 28 when the lock is released. Further, the next measurement sample number newly edited and set by the analysis procedure setting means 20 is output to the next sample discriminating means 28 via the system control means 22 to determine whether it is the same as the sample number from the autosampler operation detecting means 32. Determine.

The result is transmitted to the system control means 22.
And if it is determined that they are the same, an instruction is issued to continue the operation of the autosampler 12 and to perform injection. On the other hand, if it is determined that they are not the same, the autosampler 12 immediately starts the washing operation and instructs to discard the aspirated sample. Then, immediately after the completion of the washing, the autosampler 12 starts the suction operation of the sample to be measured next, and instructs to perform the injection after the suction is completed.

As described above, in the present embodiment, only the measurement analysis already performed at the start of the editing of the analysis sequence is continued, and during the editing, the start of the suction operation of the next sample is stopped, whereby a new measurement is started. Control not to perform analysis. Then, after the editing is completed, the suction operation of the next sample is started based on the new set value. In addition, for a sample that is being suctioned at the start of editing, injection is performed at the end of editing after determining the identity of the next measurement sample in the new setting. Further, according to the operation of the autosampler controlled during the editing, the progress and stop of the analysis time and the delay time are managed and controlled.

Therefore, in the system controller 14 according to the present embodiment, even if the currently executing step or the next step is edited, the operation of the system including the autosampler is performed regardless of the timing. Measurement values can be measured and analyzed according to the analysis sequence according to the intention of the operator to change without being different from the set values.

That is, for example, even if the sample number is changed during execution or in the next step, the consistency between the sample number specified in the analysis sequence and the actual measurement sample number is always maintained, and the sample number is changed. Addition and reduction can be easily performed. In the above embodiment, when the step currently being executed is edited, it is preferable to operate the system controller 14 as follows according to the changed item. First, the change of the analysis time is applied from the end of editing, and the analysis time of the sample being measured is also changed at the end of editing. That is, at the end of editing, the time at that point is compared with the newly set analysis time, and if the set analysis time is shorter, the analysis of the next sample is started immediately, and the set analysis time is longer. If so, continue with the current analysis. Further, the progress or stop of the analysis time at the time of unlocking, and the start of sample suction based on the analysis time are also determined based on the changed analysis time.

In changing the number of injections of the sample, the injection of the sample is controlled as follows depending on the relationship between the number of injections at the end of editing and the number of injections changed and set. 1. If (the number of injections of the sample at that time) ≧ (the number of injections after the change), the current sample number is ended, and the sample injection of the next sample number to be measured is performed based on the new analysis sequence. Start from 1. 2. If (the number of injections of the sample at that time) <(the number of injections after the change), the injection / measurement is repeated until the sample of the current sample number reaches the number of injections after the change. In addition, when changing the injection amount of the sample and the measurement conditions (system program), the change is applied from the sample to be injected the next time after the editing is completed.

As described above, the system controller according to the present embodiment can edit the currently executed step, and furthermore, the edited settings are reflected on the sample number currently being measured. It is possible to change to the optimum setting while watching, and to perform analysis and measurement immediately corresponding to the contents. So, for example, by observing the analysis,
Even if the peak elution is later than the expected time or an unexpected peak appears, changing the analysis time at that point can change the subsequent analysis time from the sample currently being analyzed. Can be prevented. If the peak elution is uncertain, for example, set the analysis time to be longer at the beginning, and after analyzing the results of several samples, shorten the subsequent analysis time to an appropriate time. And efficient measurement and analysis can be performed.

[0043]

As described above, according to the system control apparatus and the control method of the present invention, even if any subsequent steps are edited, including the step currently being executed by the analysis procedure setting means. In addition, it is possible to accurately control the operation of the system in accordance with the analysis sequence regardless of the editing timing.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a schematic configuration of a system controller according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram of a continuous analysis monitor screen when a system controller is activated.

FIG.

FIG. 4 is an explanatory diagram of an analysis sequence screen on which the contents of an analysis procedure setting unit are output.

FIG. 5 is an explanatory diagram of an injection timing of each sample in which a delay time is captured in the same step.

FIG. 6 is an explanatory diagram of a conventional sample injection timing that does not take in a delay time at a step change.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Measuring apparatus 12 ... Autosampler 14 ... System controller 16 ... Input means 18 ... Measurement condition setting means 20 ... Analysis procedure setting means 22 ... System control means 24 ... Edit detection means 26 ... Suction operation control means 28 ... Next sample determination means 30 ... time management control means 32 ... autosampler operation detection means 34 ... output means

Continuation of the front page (72) Inventor Miki Kuwashima Inside of Nihon Bunko Co., Ltd., 2967, Ishikawa-cho, Hachioji-shi, Tokyo (72) Inventor Koji Yoshida 5th Nippon Bunko Co., Ltd., 2967 Ishikawacho, Hachioji-shi, Tokyo (72) Inventor Hitomi Abe 5th Japan 2953 Ishikawacho, Hachioji-shi, Tokyo Nippon Bunko Co., Ltd. (72) Invention Shao Ping 5 Nihon Bunko Co., Ltd., 2967 Ishikawa-cho, Hachioji-shi, Tokyo (56) References JP-A-6-222830 (JP, A) JP-A-54-5793 (JP, A) JP-A-6 -265559 (JP, A) JP-A-3-191866 (JP, A) JP-T-63-502931 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 35/00- 35/10 G01N 1/00 101

Claims (4)

(57) [Claims] The present invention is used for an analyzer constituted by each measurement / analysis instrument including an autosampler, and sets conditions for measurement / analysis of each sample for each step in which the conditions are combined into a sample group, and An analysis procedure setting means capable of constantly editing the setting contents; an input means connected to the analysis procedure setting means for inputting setting and editing contents in the analysis procedure setting means; and an input means connected to the analysis procedure setting means; A system control means for controlling the operation of each measurement / analysis instrument in accordance with the conditions set and edited by the analysis procedure setting means; and a start / edit end of editing of setting contents in the analysis procedure setting means which is connected to the analysis procedure setting means. Edit detection means for performing the operation, an autosampler operation connected to the autosampler and detecting an operation state of the autosampler A means for notifying, the edit detecting means and the autosampler being connected to stop the next sample suction start of the auto sampler based on the edit start detection from the edit detect means, and restart the next sample suction start based on the edit end detection. A suction operation control means for controlling the operation of the autosampler, and a system control unit connected to the system control means, the edit detection means, and the autosampler operation detection means, based on a detection signal from the edit detection means and the autosampler operation detection means. controller autosampler, characterized in that and a time management control unit for managing and controlling the time progression and arrest in means. 2. The control device according to claim 1, wherein the suction operation control means is also connected to an autosampler operation detection means, and when the operation of the autosampler is in the course of sample suction at the time of starting editing, the sample suction is performed. Is continued to control the operation to be stopped at the time of completion of suction, and is connected to the system control means, the autosampler operation detection means, and the edit detection means, and the next measurement instructed by the system control means at the end of editing. A control device for an autosampler, comprising: a next sample discriminating means for discriminating whether or not the sample and the next injection sample which has been suctioned and detected by the autosampler operation detecting means are the same. 3. A system control method for an analyzer constituted by each measuring device including an autosampler, wherein conditions relating to measurement and analysis of each sample are input for each step in which the conditions are combined into a sample group having the same condition. An analysis step for setting and editing the conditions according to the input contents in the input step; and a system control step for controlling the operation of each measurement and analysis instrument in accordance with the conditions set and edited in the analysis procedure setting step. An editing detection step of detecting an edit start and an edit end of the setting conditions in the analysis procedure setting step; an autosampler operation detection step of detecting an operation state of the autosampler; and an edit start detection in the edit detection step. Stops the next sample from the autosampler from starting suction, and stops A suction operation control step of controlling the operation of the autosampler so as to restart the pull suction start, based on an edit start or edit end signal detected in the edit detection step, and an operation signal detected in the autosampler operation detection means A time management control step of managing and controlling time progress and stop in the system control step. 4. The control method according to claim 3, wherein if the operation of the autosampler is in the middle of sample suction at the time of start of editing in the edit detection step, the sample suction is continued, and the operation is stopped at the time of completion of suction. Controlling in the suction operation control step to stop, and at the time of editing end detection in the editing detection step, the next measurement sample to be instructed to measure in the system control step, and the completion of the suction detected in the autosampler operation detection step A next sample determination step of determining whether the next injected sample is the same as the next injected sample.