Autosampler Control
Autosampler Commands (AS/AS50)

Sample Loading and Injection

With the AS and AS50 autosamplers, sample loading and injection are two distinct events. The Load command switches the injection valve to the load position and moves the sample from the AS or AS50 inject port into the sample loop. The Inject command switches the injection valve to the inject position, which directs the pump flow through the loop. The sample is then transported from the loop to the column.

 Tip:

Clicking the Inject button on the control panel sends both the Load and the Inject commands to the autosampler.

 Note:

If the AS or AS50 is in Concentrate, Sequential Concentrate, or Simultaneous mode, separate Valve.LoadPosition and Valve.InjectPosition commands are required. See the descriptions and program examples for Concentrate and Simultaneous modes below for details.

Flush the Inject Port

The Flush and Wait commands must be in the order shown. We recommend that these commands occur either before any other Autosampler commands or after all other autosampler commands. If you use the Program Wizard to create a program (see The Program Wizard), these commands appear before the other autosampler commands in the program.

Autosampler Options

All AS and AS50 option commands must be grouped together in the Program. Place them at the beginning of the program, before t = 0.000. You do not need to specify event times for the option commands. If you use the Program Wizard to create a program, these commands are entered on the first Sampler Options page in the wizard and appear in the program after the Flush and Wait commands.

Sample Preparation

All AS and AS50 sample prep commands (Pipet, Mix, FlushSP, DelaySP, SetNeedleHeight, Dilute, Dispense, Concentrate, ReagentPrime, and ReagentFlush) must be grouped together in the program. Place them at the beginning of the program, after the AS and AS50 option commands and before t=0.000. You do not need to specify event times for the sample prep commands. Include a Wait SampleReady command after the sample prep commands to allow them to be completed before injection.

For details about the sample prep commands, see  Defining Sample Preparation Steps.

 Notes:

• If you use the Program Wizard to create a program (see The Program Wizard), the sample prep commands are entered on the second Sampler Options page in the wizard.

• The Dilute and Dispense commands are available only if the AS or AS50 is equipped with the sample preparation option.

• The Concentrate, ReagentPrime, and ReagentFlush commands require AS or AS50 (USB) Moduleware version 2.0.0 (or later). These commands are not available for the DX-LAN model of the AS50, regardless of which Moduleware version is installed in the autosampler.

In the example below, 20 µl are pipetted from vial 1 and delivered to vial 10. 200 µl are dispensed from reservoir A into vial 10. The contents of vial 10 is mixed by drawing in and expelling 100 µl of the vial contents. The mixing cycle is repeated 5 times.

 Note:

Due to space limitations here, commands are shown on two lines. In an actual program, one command must be entered on one line.

Concentrate Applications

The AS or AS50 (USB) runs in Concentrate or Sequential Concentrate mode when the mode is selected on the autosampler front panel and a concentrator column is installed. The default program for these modes has the following features:

• The Concentrate command is automatically listed on the first line of the Sample Prep Options page. You may add sample prep steps before or after this line.

• The Load, Inject, and Wait InjectState commands are not present.

• The Concentrate command includes a ValvePosition = LoadPosition parameter to switch the valve to load.

• The Sampler_InjectValve.InjectPosition command (to switch the valve to inject) is located after the Wait CycleTimeState command at time 0.00.

• The BeginOverlap command is inserted at 5.00 minutes. Sample overlap normally begins after the Wait InjectState command; however, since ReagentFlush programs do not include the Inject and Wait InjectState commands, sample overlap will start at the time specified for BeginOverlap.

• If the Sequential Concentrate mode is selected, the program also includes exclusive access commands that allow the autosampler to be shared by two timebases. Refer to  Sharing an Autosampler (AS or AS50 (USB)).

 To edit the default program, follow these guidelines:

• You may add sample prep commands before or after the Concentrate command.

• You may add or delete the Concentrate, ReagentPrime, ReagentFlush, and BeginOverlap commands as needed.

• A program may include multiple Concentrate, ReagentPrime, and ReagentFlush commands. However, if the program includes multiple BeginOverlap commands, all but the first BeginOverlap command is ignored. Make sure the multiple Concentrate or ReagentFlush commands do not exceed the volume of sample or reagent in the vial specified in the sequence.

Example Program for Concentrate Mode (Matrix Elimination)

In the following example program for the Concentrate mode, commands for the concentrate functions are in bold. Commands similar to these could be used for a matrix elimination application.

 Note:

Due to space limitations here, some commands are shown on two lines. In an actual program, one command must be entered on one line.

 Note:

In the above example program, the AspirateSpeed, and DispenseSpeed parameters for the Concentrate command require AS Moduleware version 2.0.2 (or later). These parameters are not available for the AS50 (USB or DX-LAN model), regardless of which Moduleware version is installed in the autosampler.

Relative Vial Location

In the sample preparation commands, a vial location can be specified either as an absolute position or as a relative position. In relative positioning, the CurrentVial is the current sample vial position, specified in the sample list in the Sequence. In the example below, 20 µl of liquid are pipetted from the current sample vial and then expelled into the vial, 1 position past the current vial.

Sample Overlap

If the AS or AS50 Sample Overlap option is enabled in the Server Configuration, the autosampler performs the following commands for the next sample in a sequence, while data acquisition is occurring for the currently running sample in the sequence:

• Flush

• Autosampler Option Commands (ColumnTemperature, TrayTemperature, WaitForTemperature, SyringeSpeed, CycleTime, NeedleHeight, CutSegmentVolume)

• Sample Prep Commands (Pipet, Mix, DelaySP, FlushSP, SetNeedleHeight, Dilute, Dispense, Concentrate, ReagentPrime, ReagentFlush)

When the autosampler is preparing a sample, the Status field in the sequence displays Preparing and the sample line is in yellow. A message is also logged in the Audit Trail.

Sample overlap is not allowed when the autosampler is running in the Sequential or Sequential Concentrate mode.

Also, refer to  Overlapping Samples.

Cycle Time

Cycle time controls the time between injections. When a cycle time is specified, the autosampler delays sample injection until the specified time has elapsed since the previous injection. This is accomplished with the Wait CycleTimeState command. When running a batch, the Wait CycleTimeState command in the first program in the batch is ignored.

The following example sets a cycle time of 30 minutes.

Priming the Liquid Lines

The Prime command is used to prime the flush reservoir line to the sampling valve and the sample transfer line. In addition, if the sample prep option is installed, the Prime command is used to prime the lines from each installed reagent reservoir. The following example uses the prep syringe to prime the line to reservoir A with 2000 µl.

Simultaneous Mode

If the Simultaneous mode is selected on the AS or AS50 front panel, the program includes additional commands for controlling two injection valves. The additional commands are used to switch the position of each valve during sample injection.

In the following example, an AS50 is connected to two ICS-2000 systems. Each ICS-2000 is equipped with an injection valve; no injection valves are installed in the AS50.

 Note:

For an overview of the individual commands for the autosamplers, refer to  Dionex AS/AS50 Autosamplers.