TECHNICAL FIELD

The present invention relates to a sample plate in which a plurality of wells each for accommodating a container containing a sample or a sample itself is provided on a principal plane, and also relates to an auto-sampler configured to allow an access to a desired well of the sample plate using a sampling needle.

BACKGROUND OF THE INVENTION

As an auto-sampler of a liquid chromatograph, there is an auto-sampler provided with a sample rack for installing a sample plate having a plurality of wells each for accommodating a container containing a sample or a sample itself. In such an auto-sampler, a plurality of sample plates is generally installed in the same plane so as not to overlap each other (see Patent Document 1).

On the other hand, there are some auto-samplers in which a plurality of sample plates is arranged in the up-down direction in multiple stages. In such an auto-sampler, since a sampling needle cannot access sample plates other than a sample plate installed in the uppermost stage in a state in which sample plates are arranged so as to overlap with each other, the auto-sampler is configured so that each sample plate can be moved to a position where the sampling needle can access each sample plate as required.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-176749

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In a system in which a plurality of sample plates is installed in the same plane, the installation area of the auto-sampler becomes large. On the other hand, in a system in which a plurality of sample plates is arranged in the up-down direction in multiple stages, the mechanism for moving the respective sample plates is required, which increases cost.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to increase the number of installable sample plates in an auto-sampler without increasing cost.

Means for Solving the Problem

A sample plate according to the present invention has a principal plane in which a plurality of wells is arranged. The sample plate has a plurality of through-holes each allowing a sampling needle to pass through in a region of the principal plane where the wells are not provided. Positions of the wells and positions of the through-holes are designed so that when two pieces of the sample plates are arranged up and down with a predetermined positional relationship in a state in which respective principal planes are arranged in parallel each other, the plurality of through-holes of the sample plate arranged on an upper side is arranged at positions directly above respective wells of the lower sample plate.

That is, in the sample plate according to the present invention, even if two pieces of the sample plates are arranged up and down, a sampling needle can access the wells of the lower sample plate through the through-holes provided in the sample plate arranged on an upper side.

The sample plate according to the present invention is preferably provided on a lower surface side thereof with a protrusion configured to be inserted into the through-hole of the other sample plate arranged on a lower side of the sample plate when the sample plate is arranged on the upper side of the other sample plate. With this configuration, the positional relationship of both the sample plates can be fixed by inserting the protrusion provided on the lower surface side of the sample plate into the through-hole of the sample plate arranged on the lower side thereof.

On the upper surface of the sample plate, a sheet for sealing the upper surface of the well to prevent the liquid from evaporating may sometimes be arranged. Such a sheet is made of an elastic material such as silicone and can be penetrated by a sampling needle. When such a sheet is arranged on the upper surface of the sample plate, it is conceivable that the protrusion provided on the lower surface side of the sample plate is less likely to be inserted into the through-hole of the sample plate arranged on the lower side thereof. Therefore, the protrusion preferably has a shape with a pointed lower end. When the tip end of the protrusion is sharp, the tip end of the protrusion can penetrate the sheet covering the upper surface of the lower sample plate.

Further, the sample plate of the present invention is preferably provided with a downwardly protruding ridge portion on the lower surface side, and when the sample plate is arranged on a lower side of the other sample plate with a predetermined positional relationship in a state of being stacked up and down, a groove configured to fit the ridge portion of the other sample plate arranged on an upper side of the sample plate may be provided on an upper surface side of the sample plate. With this, it is easy to arrange two pieces of sample plates in a state of being stacked up and down with a predetermined positional relationship.

In cases where the upper surface of the sample plate is covered with a sheet made of an elastic material to seal the openings of the wells, the groove may be provided on an upper surface of the sheet. With this, even in cases where the upper surface of the sample plate is covered with a sheet, it is easy to arrange two pieces of the sample plates in a state of being stacked up and down with a predetermined positional relationship.

A plurality of through-holes each allowing the sampling needle to pass through may be provided in the sheet at positions corresponding to the plurality of through-holes of the sample plate.

The auto-sampler according to the present invention is provided with a sample plate installation member, a sampling needle, and a needle control unit. The sample plate installation member is a sample plate installation member for installing the above-mentioned sample plate, and is configured to allow a plurality of the sample plates to be arranged up and down in two stages with a predetermined positional relationship such that the plurality of through-holes of the sample plate arranged on the upper side is arranged at positions directly above respective wells of the sample plate arranged on a lower side. The sampling needle is for sucking liquid from the well of the sample plate or discharging the liquid to the well, and has mobility. The mobile means that it can be moved in the horizontal direction or vertical direction by a drive mechanism. The needle controller is configured to drive the sampling needle such that, when sucking or discharging the liquid from or to a target well which is the well of the lower sampling plate of two pieces of the sample plates installed on the sample plate installation member up and down with the predetermined positional relationship, the sampling needle is lowered from a position directly above the through-hole of the sample plate arranged on an upper side directly above the target well to pass through the through-hole so that a tip end of the sampling needle reaches the target well.

That is, the auto-sampler according to the present invention is configured such that the above-mentioned sample plates can be installed up and down in two stages, namely, the sampling needle can access either the upper sample plate or the lower sample plate installed in two stages.

In the auto-sampler of the present invention, the sample plate installation member may be provided with an upper sample rack and a lower sample rack for mounting the upper sample plate and the lower sample plate independently of each other, respectively. In this instance, the upper sample rack is provided with through-holes each allowing the sampling needle to pass through at positions corresponding to the through-holes of the upper sample plate installed on the upper sample rack.

Effects of the Invention

In the sample plate according to the present invention, since the sampling needle can access the well of the lower sample plate through the through-hole provided in the upper sample plate even if two pieces of the sample plates are arranged up and down, a plurality of sample plates can be arranged so as to be stacked up and down without providing a mechanism for moving the sample plates. With this, the installable number of the sample plates can be increased while suppressing the expansion of the installation area of the auto-sampler.

The auto-sampler according to the present invention is configured such that the above-mentioned sample plates can be installed up and down in two stages, and the sampling needle can access both the upper sample plate and the lower sample plate installed in two stages. Therefore, the number of installable sample plates can be increased while suppressing the expansion of the installation area of the auto-sampler without providing a mechanism for moving the sample plates.

