Firma:              Merck-Hitachi

Modell:                         L-7200

Kommentar:     Dokumente engl.

Application

This instrument is used in combination with a liquid chromatography system to perform automatic analyses.

Configuration

The configuration of the L-7200 Autosampler is shown in Figure 3-1.

Samples to be analyzed are stored in a rack which is placed in a chamber that includes a syringe to allow aspiration of the samples can be moved along the transverse axis (X), the longitudinal axis (Y), and the vertical axis (Z). The injection valve is used to inject samples into the mobile phase flow. Syringes with a delivery volume of 0.1 and 0.5mL are available.

Analytical conditions are set via the keys on the keypad. The display panel presents information about the operational status of the system.

Flow path

Figure 1-3 includes the various components of the system that are

in contact with the sample and the wash solution in the L-7200

Autosampler. The needle can be moved along the X, Y and Z

axes to permit free movement between sample vials, the wash

port and the injection port. The action of the syringe is used to

withdraw sample from the sample vial and to deliver lt to the

injection port.

A cycle includes the following steps:

* The needle is cleaned in the wash port

* A sample solution is aspirated by the needle

* The sample solution is Ioaded into the loop of the injection valve

* The valve is switched to inject the sample into the mobile phase

Sample Injection Methods

The L-7200 permits three injection methods. In the standard injection method, the amount of sample that is withdrawn by the needle is slightly larger than the amount of sample that will be transferred from the injection valve to the column. The middle part of the sample is injected; the leading and trailing ends of the sample are not injected. This method is commonly called the cut injection method.

If the amount of a sample is small, the entire sample that is withdrawn via the needle is transferred into the sample loop and into the column. This method is called the all volume injection method.

In the full loop injection method, sample loop is filled with sample for measurement.

Cut lnjection Method

This method provides good reproducibility, however some of the sample is wasted.

Specifications

(1)      Number of standard samples: 80

         The vial number setting range is from 1 to 200

(2)      Rack/sample vials:

         Conditions can be set to accommodate a variety of sample vials and racks

(3)      Syringe capacity:

          0.5 mL (standard syringe)

(4)      Sample injection volume:

         0.5 pL to 400 pL (standard loop: 100 pL)

(5)      Syringe speed:

          5 speeds can be chosen by the analyst

(6)      Sample injection method:

          Syringe measurement cut injection

          Synnge measurement all volume injection

          Full loop measurement injection

(7)      Pressure resistance: 34 MPa (350 kgf/cm ² )

(8)      Composition of components that are in contact with liquid:

         Stainless steel (SUS316), tetrafluoroethylene (Teflon), borosilicated glass,      Vespel, PEEK (polyethy lether ketone)

(9)      Display:

          LCD with back light (40 characters x 2 lines)

(10)    Control system:

          Sequential injection function for LC

(11)    Vial detecting function:

          Provided

(12)    Data storage:

          Battery backed-up memory

(13)    Number of injections per sample:

          Up to 99 times

(14)    Analysis time:

          999.9 minutes

(15)    Extemal communication function:

          D-Line communication

(16)    GLP function:

         Error detection: Abnormality in operation of the system is detectable.

         Maintenance logbook:      After part replacement, the number of injections is                                     recorded. The count can be reset to zero after certain                              parts (e.g. injection port seal) have been replaced.

(17)    Ambient temperature:

          4 to 35°C

(18)    Ambient humidity:

          45 to 85%

(19)    Power requirement:

          100- 240 V AC ± 10%, 50/60 Hz

(20)    Power consumption:

          Approx. 85 VA

(21)    Dimensions:    

          260(W) x 500(D) x 235(H) mm (excluding protrusions)

(22)    Weight:

          Approx. 19 kg