INDICATOR STRIP

• US 3,715,192 A
• Filed: 08/07/1970
• Issued: 02/06/1973
• Est. Priority Date: 08/12/1969
• Status: Expired due to Term

• Current Assignee: Adolf Wenz, Alfred Stein, Dieter Schmitt
• Original Assignee: Adolf Wenz, Alfred Stein, Dieter Schmitt
• Inventors: Stein, Alfred, Schmitt, Dieter, Wenz, Adolf
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Reese, R. M.
• Application Number:
  US05/062,017
• Time in Patent Office: 914 Days
• Field of Search: 23/230,232,253,253TP,254
• US Class Current: 422/421
• CPC Class Codes: C12Q 1/46 involving cholinesterase
• CPC Class Codes: G01N 33/525 Multi-layer analytical elements

Abstract

An indicator strip, useful in analytical chemical procedures, which comprises an impregnated capillary material having at least a partially transparent film on one side and on the other side, a film forming a hollow space which is in communication with said capillary material.

Claims

1. An indicator strip characterized by quick absorption of a liquid medium to be analyzed, comprising at least one absorbent, reagent-impregnated capillary material disposed between liquid-impermeable films, wherein at least one of said films is at least partially transparent, said strip having open ends and said capillary material having its edges exposed at least at said ends, and at least one slot extending longitudinally through said strip to said open ends and disposed adjacent said capillary material.

2. An indicator strip in accordance with claim 1 wherein the said slot extends over at least 40 percent of a surface of the impregnated absorbent capillary material.

3. An indicator strip in accordance with claim 1 wherein said capillary material contacts one of said films on one side, and wherein said slot is between said other film and said capillary material.

4. An indicator strip in accordance with claim 1 wherein said slot is subdivided into several smaller slots.

5. An indicator strip in accordance with claim 1 wherein said capillary material is also exposed on at least one of its lateral edges.

6. An indicator strip in accordance with claim 1 wherein said capillary material is exposed on all of its edges.

7. An indicator strip in accordance with claim 1 wherein the ratio of the thickness of said capillary material to the maximum height of said slot, in cross section, is about 1 :

0.5 to about 1 ;

10.

8. An indicator strip in accordance with claim 1 wherein the ratio of the thickness of said capillary material to the maximum height of said slot, in cross section, is about 1 :

1 to about 1 ;

2.

9. An indicator strip in accordance with claim 1 wherein said capillary material has a thickness of about 0.05 to 3 mm.

10. An indicator strip in accordance with claim 1 wherein the capillary material is filter paper.

11. An indicator strip in accordance with claim 1 wherein said strip has a length of about 30 - 100 mm., and a width of about 3 - 10 mm.

12. An indicator strip in accordance with claim 1 wherein said strip has a length of about 50 - 70 mm., and a width of about 5 -7 mm.

13. An indicator strip in accordance with claim 1 wherein said capillary material has a surface of about 10 - 50 mm2 and an approximately square configuration.

14. An indicator strip in accordance with claim 1 wherein said capillary material has been impregnated in situ.

15. AN indicator strip in accordance with claim 1 wherein one of said films is transparent.

16. An indicator strip in accordance with claim 1 wherein one of said films forming said slot has a geometrical configuration.

17. An indicator strip in accordance with claim 1 wherein said film forming said slot has a patterned inner surface.

18. An indicator strip in accordance with claim 1, comprising at least two adjacent indicator strips wherein each of said strips is independent from the other and comprises a said capillary material and a said slot, and each of said strips have common films.

19. An indicator strip in accordance with claim 1 wherein said slot is partially filled by projections extending from the inner side of one of said films.

20. An indicator strip in accordance with claim 19 wherein up to about 60 percent of the volume of said slot is filled by said projections.

21. An indicator strip in accordance with claim 1 wherein said capillary material is disposed on one of said films and between hydrophobic separating layers.

22. An indicator strip in accordance with claim 21 wherein the ratio of the thickness of the said capillary material to the thickness of said hydrophobic separating layers is about 1 :

0.5 to about 1 ;

10.

23. An indicator strip in accordance with claim 21 wherein the ratio of the thickness of the said capillary material to the thickness of said hydrophobic separating layers is about 1 :

1 to about 1 ;

2.