METHOD AND DEVICE FOR THE OPTICAL SCANNING OF A CHROMATOGRAPHIC SAMPLE

Abstract

A method and device for the optical scanning of a chromatographic sample (3), where a sample plate (2) holding the sample (3) is illuminated with light from a first illumination device (13) and the light emitted by the sample plate (2) is detected by an optical detector device (15) which detects in cell form or area form, a second illumination device (14) is preferably firstly activated in a preparation step. The sample plate (2) is displaced in a first displacement direction relative to the detector device (15), illuminated by the first illumination device (13) and a first measurement image is recorded. The sample plate (2) is displaced in a second displacement direction relative to the detector device (15), illuminated by the second illumination device (14), and a second measurement image is recorded.

Claims

1. Method for the optical scanning of a sample (3), where a sample plate (2) holding the sample (3) is, in a first measurement step, illuminated at least with light from a first illumination device (13) and the light emitted by the sample plate (2) is detected by means of an optical detector device (15) which reads line by line or field by field and a first measurement image of the sample plate (2) is recorded, where the sample plate (2) is displaced in a first displacement direction relative to the detector device (15), and where, in a subsequent second measurement step, the sample plate (2) is displaced in a second displacement direction relative to the detector device (15), illuminated by means of the second illumination device (14) and a second measurement image of the sample plate (2) is recorded.

2. Method according to claim 1, characterised in that, in a subsequent third measurement step, the sample plate (2) is displaced in a third displacement direction relative to the detector device (15), illuminated by means of a third illumination device (20) and a third measurement image of the sample plate (2) is recorded.

3. Method according to claim 1, characterised in that the second illumination device (14) and/or third illumination device is activated in a preparation step before and/or during a preceding measurement step.

4. Method according to claim 1, characterised in that light generated by the second illumination device (14) is screened off from the sample plate (2) during the first measurement step.

5. Method according to claim 1, characterised in that the second displacement direction is opposite to the first displacement direction.

6. Method according to claim 1, characterised in that information from the first measurement image is used for the recording of the second measurement image.

7. Method according to claim 1, characterised in that the illumination devices (13, 14) and the detector device (15) are located above the sample plate.

8. Device (1) for the optical scanning of a chromatographic sample (3) having a holder for a sample plate (2) having a first illumination device (13) and having an optical detector device (15), characterised in that the detector device (15) reads line by line or field by field, in that the holder has a carrier (5) for the accommodation of the sample plate (2) which can be displaced in a first displacement direction relative to the detector device (15), in that the first illumination device (13) and a second illumination device (14) each extend over a maximum width of a sample plates (2) which can be accommodated in the holder and are each orientated parallel to the line-by-line or field-by-field detector device (15) and perpendicular to the first displacement direction.

9. Device (1) according to claim 8, characterised in that the carrier is a drawer (5).

10. Device (1) according to claim 8, characterised in that a wavelength part-range is screened off from the sample plate (2) during a recording of a measurement image.

11. Device (1) according to claim 8, characterised in that the detector device (15) is arranged less than 100 mm, preferably less than 30 mm, above the carrier (5).

12. Device (1) according to claim 9, characterised in that the device (1) has a housing (4) in which the first illumination device (13) and the second illumination device (14), the optical detector device (15) and the drive device (6) for the drawer (5) are arranged, and in that the housing (4) has a drawer slot (9) through which the drawer (5) can be partly moved out of the housing (4) and can be moved into the housing (4).

13. Device (1) according to claim 12, characterised in that the drawer slot (9) has a sensor device for detecting a sample plate (2).

14. Device (1) according to claim 12, characterised in that the housing (4) has an exit slot for the drawer (5) on a housing side opposite the drawer slot (9).

15. Device (1) according to claim 8, characterised in that the detector device (15) is arranged between the first illumination device (13) and the second illumination device (14).

Description

[0057] Illustrative embodiments of the inventive idea are explained in greater detail below and are depicted in the drawing, in which:

[0058] FIG. 1 shows a diagrammatic representation of a device for the optical scanning of a sample plate holding a plurality of samples,

[0059] FIG. 2 shows a diagrammatic sectional view of the device shown in FIG. 1 along a section plane II-II in FIG. 1

[0060] FIG. 3 is a sectional view of the device shown in FIGS. 1 and 2 along a section plane III-III in FIG. 2, where the sample plate has been moved completely into a housing of the device,

[0061] FIG. 4 is a diagrammatic representation of a measurement head of the device having a detector device and having three illumination devices, and

[0062] FIG. 5 is a diagrammatic representation of a different design of a measurement head of the device having one detector device and having two illumination devices.

[0063] A device 1, depicted by way of example in FIGS. 1 to 3, for the optical scanning of a sample plate 2 on which a plurality of chromatographic samples 3 are arranged has a housing 4 and a drawer 5 stored therein in a displaceable manner. The drawer 5 can be moved to and fro along a displacement direction, indicated by an arrow 7, by means of a drive device 6. During this movement, the drawer 5 can be moved partly out of the housing 4 through a drawer slot 9 parallel to a housing base 8 and moved back into the housing 4.

[0064] In FIGS. 1 and 2 the drawer 5 is depicted in a state moved completely out or partly out. The drawer 5 has a recess 10, accessible from above, in which the sample plate 2 is located. The sample plate 2 is pushed into a corner of the recess 10 by spring tongues 11 arranged laterally in the recess 10 and thus positioned reliably within the recess 10, which is larger than the sample plate 2 located therein. In this way, it is possible to position the plate formats of, for example, 20×20 centimetres or 20×10 centimetres usually used for thin-layer chromatography in the recess 10 of the drawer 5.

[0065] A measurement head 12 is fixed in the housing above the drawer 5. A first illumination device 13, a second illumination device 14 and a line-by-line or field-by-field optical detector device 15 are arranged on an underside of the measurement head 12, facing the drawer 5, in such a way that light emitted by the first illumination device 13 or by the second illumination device 14 illuminates a region of the sample plate 2 located below the measurement head 12 and the light emitted by the sample plate 2 can be detected and recorded by the detector device 15. The first illumination device 13 emits, for example, light in a visible wavelength region. The second illumination device 14 emits, for example, UV light. Both light in the visible wavelength region and also the visible luminescence generated by the excitation with UV light can be detected and recorded by means of the detector device 15 scanning line by line or field by field.

[0066] In order to carry out a measurement, firstly the sample plate 2 must be placed in the recess 10 of the drawer 5 and fixed, for example with the aid of the spring tongues 11. Before the beginning of a first recording, the second illumination device 14 is activated and pre-warmed. The second illumination device 14 is covered by means of a cover, which is not depicted in FIGS. 1 to 3, in order to prevent UV light from falling on the sample plate 2 during the pre-warming time and the performance of a first recording. The first illumination device 13 is likewise activated and the drawer 5, which is still moved out of the housing 4, is pulled evenly into the housing 4 and moved past below the detector device 15 in the process. During the pulling-in of the drawer 5, the sample plate 2 arranged in the recess 10 is illuminated with visible light from the first illumination device 13 and the light emitted by the sample plate 2 is detected by the detector device 15. In this way, a first measurement image is recorded.

[0067] After the sample plate 2 has been moved completely past the detector device 15, the first illumination device 13 is switched off and the cover is removed from the second illumination device 14, so that the sample plate 2 is no longer illuminated with visible light, but instead with UV light. In order to record the second measurement image, the drawer 5 with the sample plate 2 accommodated therein is again moved in an opposite displacement direction below the detector device 15 scanning line by line or field by field and moved out of the housing 4 through the drawer slot 9 in the process. Since the second illumination device 14 has been pre-warmed during the recording time of the first measurement image, the sample plate 2 is illuminated uniformly by the second illumination device 15 during the recording of the second measurement image.

[0068] The first illumination device 13, the second illumination device 14 and the detector device 15 are each designed in strip form or tube form and are arranged, or oriented, in the housing 4 perpendicularly to the displacement direction indicated by means of the arrow 7. The first illumination device 13, the second illumination device 14 and a detector device 15 each extend with their ends or with their detection region respectively beyond the edges of the recess 10 in the drawer 5, so that very homogeneous illumination and illumination strength can be achieved over the entire area of the sample plate 2.

[0069] In order to be able to evaluate the individual measurement images as precisely as possible, a reference strip 16, which can likewise be illuminated during a measurement operation and recorded in the measurement image together with the sample plate 2, is optionally installed on the drawer 5 laterally alongside the recess 10.

[0070] Instead of a reference strip, the brightness in the regions which do not contain a sample is preferably measured and utilised as reference.

[0071] In order to prevent ambient light from entering the housing 4 through the drawer slot 9 during a measurement and affecting the measurement results, and in order to prevent UV light from unintentionally escaping from the housing 4, the drawer slot 9 optionally has a brush strip 17 below the drawer 5 and preferably a screening strip 18 above the drawer 5. The screening strip 18 is mounted in a pivotable manner and at the same time serves as sensor device. If a sample plate 2 has not been placed correctly in the recess 10 of the drawer 5 or if additional objects are located on an upper side of the drawer 5 and the pivotable screening strip 18 is therefore deflected during a displacement of the drawer 5, the measurement operation can be interrupted and, for example, a safety switch-off of the illumination devices 13 and 14 and of the drive can be carried out.

[0072] The influences of ambient light can be reduced further by a suitable nature of the inside wall of the housing. The inside of the housing is preferably black, it is particularly preferably black and anodised.

[0073] A contact-sensitive display 19 enables simple operation of the device 1 and can at the same time be used to display initial information during performance of a measurement operation.

[0074] In a further embodiment, not depicted in the figures, the screening-off of ambient light or UV light does not take place or does not take place only by screening strips or screening brushes, but instead merely or additionally by other screening devices, such as, for example, flaps, curtains, etc.

[0075] The two or more illumination devices and the detector device comprising one or more sensor devices are preferably located above the carrier in a fixed, non-movable measurement head 12. The measurement head may furthermore contain screening devices and optical devices, such as mirrors or lenses, which support image acquisition, or also light-refracting and/or light-scattering elements which enable more homogeneous illumination.

[0076] Various embodiments of the measurement head 12 are conceivable in order to be able, using the device, to record, as rapidly as possible, various measurement images which can be used together for the evaluation of the chromatographic separations of a sample plate 2. FIG. 4 shows diagrammatically a measurement head 12 in which, in addition to the detector device 15 and the first illumination device 13 and the second illumination device 14, a third illumination device 20 is arranged. The first illumination device 13 emits light in a visible wavelength region. The second illumination device 14 is a mercury vapour lamp, which, through suitable optical elements, emits UVC light having a wavelength of typically 254 nm or a plurality of UV LEDs arranged in strip form. The third illumination device 20 has a number of light-emitting diodes arranged in strip form or a mercury vapour lamp, which likewise, in combination with suitable optical components, emits light having a wavelength of typically 366 nm and having a very homogeneous illumination strength.

[0077] In order to prevent UV light from the second illumination device 14 being collected and acquired by the detector device 15 during the pre-warming time of the second illumination device 14 and the simultaneous recording of a first measurement image, a screening device 21 which is opaque to UV light may screen off the detector device 15 during the first measurement operation. The first illumination device 13, which emits visible light, and the third illumination device 20, consisting, for example, of LEDs, do not require a pre-warming time and can each be activated for the duration of the measurement operation in question and subsequently switched off again.

[0078] In the variant depicted in FIG. 5, the measurement head 12 has in each case a displaceable screening device 22 in front of the first illumination device 13 and in front of the second illumination device 14, by means of which the illumination device 13, 14 in question can be screened or uncovered.

[0079] Using the device 1 according to the invention, measurements of chromatographic sample plates 2 can be carried out very rapidly. However, other measurements are also possible with the device 1, for example quality tests, particle analyses or detection of security pigments. Further chemical or biological evaluations, for example of gels, agar plates, test sticks, etc., are also possible. In accordance with the invention, sample plates are therefore all samples which can be accommodated by a carrier of a device according to the invention, such as thin-layer chromatography plates, gels, agar plates, test sticks, printed circuit boards, etched circuit boards, tissue sections, samples of paper, plastic, metal, minerals, granules. The sample plate is preferably a thin-layer chromatography plate. In accordance with the invention, the carrier is able to accommodate one or more sample plates.

[0080] The carrier, for example in the form of a drawer 5, can also be removed completely from the housing 4 and re-used for carrying out measurements. Thus, for example, the sample plate 2 may already be arranged in the drawer before or during the chromatographic separation of the samples arranged thereon and thus stored and transported in a protected manner during preparatory or subsequent method steps.

[0081] Even without further comments, it is assumed that a person skilled in the art will be able to utilise the above description in the broadest scope. The preferred embodiments and examples should therefore merely be regarded as descriptive disclosure which is absolutely not limiting in any way.

[0082] The complete disclosure content of all applications, patents and publications mentioned above and below, in particular the corresponding applications EP 14004313.4, filed on 19 Dec. 2014, and EP 15000889.4, filed on 26 Mar. 2015, is incorporated into this application by way of reference.