Abstract: A chemical sensor having a field-effect transistor as an electronic transducer and used for the analysis of specific constituents in a liquid, the chemical sensor comprising means which permits an externally supplied sample solution to reach a chemical receptor of said chemical sensor but substantially prevents external light from reaching said field effect transistor.

Abstract: A method for quantitative determination of bilirubin is disclosed. The method comprises bringing a bilirubin-containing aqueous liquid sample into contact with a hydrophobic bilirubin extracting composition containing a hydrophobic amine capable of extracting bilirubin. The amine extracts the bilirubin in said aqueous liquid sample. Photometry is then used to determine the concentration of bilirubin extracted with the bilirubin extracting composition. A device for use in this method is also disclosed. The device has a layer containing a hydrophobic bilirubin extracting composition containing a hydrophobic amine capable of extracting bilirubin.

Abstract: In a device for measuring ion activity in a liquid sample such as a body fluid comprising at least one pair of ion-selective electrodes selectively responsive to a specific ion, a porous liquid distributing member for feeding a liquid sample to one electrode of the pair of electrodes, a porous liquid distributing member for feeding a reference liquid to another electrode of the pair of electrodes and a porous bridge for electrically connecting both liquids to each other, the improvement wherein the liquid distributing members are made of a nonwoven fabric composed of cellulosic long fibers.

Abstract: A dual pipette device comprises a pair of housings joined rotatably around a vertically extending axis or disposed for lateral movement, a pair of cylinders disposed respectively at lower sections of the housings, a pair of piston members extending vertically, supported by the housings or the cylinders, and respectively having lower end portions vertically slideable in the cylinders, and dropping tip fitting sections disposed at lower end of the housings or the cylinders so that the dropping tip fitting sections communicate with the cylinders. The piston members are provided with a lock member for locking them to each other when the housings are rotated or laterally moved and the distance between the piston members becomes not larger than a predetermined distance, so that the piston members are vertically slideable integrally with each other.

Abstract: In a method of measuring ion activity of a liquid sample comprising steps of spotting a reference liquid and the liquid sample on surfaces of ion-selective membranes, respectively, of at least a pair of ion-selective electrode sheets which is electrically insulated from each other, said ion-selective membranes being provided on the top of said ion-selective electrode sheets; and measuring a potential difference between the ion-selective electrodes under the conditions that both liquids are electrically connected to each other by a bridge, the improvement wherein:said each ion-selective electrode sheet is arranged upside down in such a manner that the ion-selective membrane is positioned on the lowest side;andsaid each liquid spotted from the upper side is temporarily conveyed downwardly to the lower level than the surface of the ion-selective membrane or the spotting is done on the lower level than the surface of the ion-selective membrane, and then conveyed upwardly to the surface of the ion-selective membra

Abstract: An ionic activity measuring device comprises ion selective electrodes, porous liquid distributing members for distributing a reference solution and a sample solution to the ion selective electrodes, a frame for housing the ion selective electrodes and the porous liquid distributing members and provided with a pair of liquid feed holes for feeding the reference solution and the sample solution to the porous liquid distributing members, and a porous bridge for achieving electrical conduction between the reference solution and the sample solution fed in drops to the liquid feed holes. The porous bridge is disposed in a recess formed in the surface of the frame so that the depth of the recess is not smaller than the height of the porous bridge. End portions of the porous liquid distributing members are protruded to regions under the liquid feed holes so that the fed solutions may enter from side faces of the end portions. The porous bridge may extend at positions deviated from centers of the liquid feed holes.

Abstract: In a chlorine ion-selective electrode for analysis of chlorine ion in a liquid sample which comprises a silver metal layer, a silver chloride layer and a chlorine ion-selective membrane, superposed in order, the chlorine ion-selective membrane containing a hydrophobic organic polymer as a binder, the improvement wherein the hydrophobic organic polymer is a vinyl acetal polymer such as vinyl butyral or a copolymer of a vinyl acetal and at least one monomer copolymerizable therewith such as a copolymer of vinyl butyral and vinyl alcohol.

Abstract: A duplex pipette comprises a housing, a pair of cylinders separately formed in the housing to extend substantially in parallel to each other, first and second piston members each having a lower end portion slidably received in one of the cylinders and a handle portion projecting outside the cylinder, and a pair of pipette tips mounted on the lower end of the housing by way of a connecting member, each of the pipette tips having a passage which communicates one of the cylinders with the outside of the housing. The connecting member is arranged so that the distance between the distal ends of the pipette tips can be changed. One of the piston members is arranged to be movable separately from the other piston member and the other piston member is arranged to be movable only together with said one piston member.

Abstract: A multi-layered, chemical analysis material for analysis of an aqueous liquid, which comprises in one embodiment(a) a light-transmitting, water-impermeable support having provided thereon in sequence(b) a reagent layer and(c) a porous, sample-spreading layer, with(i) the reagent layer (b) containing a lake dye precursor dispersed in a hydrophilic binder,(ii) urease incorporated in the reagent layer (b) or in a layer adjacent the reagent layer (b), and(iii) a lake forming metal salt or lake forming metal oxide, which does not substantially inhibit the activity of urease, incorporated in the reagent layer (b) or in a layer adjacent the reagent layer (b) or a lake forming metal salt or oxide incorporated in a layer adjacent the reagent layer (b); and in a second embodiment the chemical analysis material includes(d) a radiation-blocking layer interposed between said reagent layer (b) and said porous, sample-spreading layer (c).

Abstract: An integral ion selective electrode for the analysis of a potassium ion comprising:(I) a support;(II) an electroconductive metal layer such as a silver metal layer;(III) a layer of a water-insoluble salt of said metal such as a silver chloride layer;(IV) an electrolyte layer which comprises crystalline electrolyte salts of cations including a potassium ion and a sodium ion with the same anions as the anion of the water-insoluble salt, said electrolyte layer being substantially free from a binder; and(V) a potassium ion selective layer.

Abstract: In a method of measuring ion activity of a liquid sample comprising steps of spotting a reference liquid and the liquid sample on surfaces of ion-selective membranes, respectively, of at least a pair of ion-selective electrode sheets which is electrically insulated from each other, said ion-selective membranes being provided on the top of said ion-selective electrode sheets; and measuring a potential difference between the ion-selective electrodes under the conditions that both liquids are electrically connected to each other by a bridge, the improvement wherein:said each ion-selective electrode sheet is arranged upside down in such a manner that the ion-selective membrane is positioned on the lowest side; andsaid each liquid spotted from the upper side is temporarily conveyed downwardly to the lower level than the surface of the ion-selective membrane, and then conveyed upwardly to the surface of the ion-selective membrane so as to reach the surface of the ion-selective membrane.

Abstract: A conductive layer is formed on an insulating base, and at least one groove is formed in the conductive layer by cutting a part of the material of the conductive layer so that the conductive layer is divided into at least a pair of portions electrically isolated from each other by the cut groove. Thereafter, an ion selective layer is formed on the conductive layer to cover substantially the entire surface of the conductive layer including the cut groove.

Abstract: A probe assembly has at least two pairs of probes and a relay for switchably connecting any one pair of the probes to a single electric impedance lowering means. When the pairs of probes are brought into contact with terminals of at least two pairs of ion-selective electrodes of an ionic activity device, the potential difference generated between each pair of said electrodes is successively transferred to a measuring means by way of the electric impedance lowering means.

Abstract: An integral ion selective electrode for analysis of a potassium ion, etc., comprising:(I) a support;(II) an electroconductive metal layer such as a silver metal layer;(III) a layer of a water-insoluble salt of said metal such as a silver chloride layer;(IV) an electrolyte layer which comprises electrolyte salt of a sodium ion with the same anion as the anion of the water-insoluble salt, said electrolyte salt having a mean crystal size of not more than 8 .mu.m, and said electrolyte layer being substantially free from a binder; and(V) an ion selective layer selected from the group consisting of a potassium ion selective layer, a halogen ion selective layer and a carbonate ion selective layer.

Abstract: An apparatus for measuring ionic activity has a nozzle connected to a reservoir containing a reference solution. The reference solution is pumped up from the reservoir without coming into contact with air, so as to be quantitatively dripped through the nozzle when a slide-type ionic activity measuring device is located at a position below the nozzle. After the reference and sample solutions are spotted on the ionic activity measuring device, at least one pair of probes comes into contact with the device so as to measure potential difference corresponding to ionic activity difference of at least one ion between the reference and sample solutions.

Abstract: An apparatus for measuring ionic activity is comprised of a rotatable turret and at least one pair of vertically movable probes. The turret intermittently conveys slide-type ionic activity measuring devices, one by one, on each of which are spots of reference and sample solutions, to a measuring section where the probes come into contact with the measuring device so as to measure the potential difference corresponding to the difference in ionic activity of a specific ion between the reference and sample solutions. After measurement the turret further conveys the device to a discharging section where the device is automatically discharged.

Abstract: A method for quantitative determination of bilirubin is disclosed. The method comprises bringing a bilirubin-containing aqueous liquid sample into contact with a hydrophobic bilirubin extracting composition containing a hydrophobic amine capable of extracting bilirubin. The amine extracts the bilirubin in said aqueous liquid sample. Photometry is then used to determine the concentration of bilirubin extracted with the bilirubin extracting composition. A device for use in this method is also disclosed. The device has a layer containing a hydrophobic bilirubin extracting composition containing a hydrophobic amine capable of extracting bilirubin.

Abstract: An integral ion selective electrode for the analysis of a potassium ion comprising a support, an electroconductive metal layer such as a silver metal layer, a layer of a water-insoluble salt of said metal such as a silver chloride layer, an electrolyte layer which comprises an electrolyte salt of a potassium ion with the same anion as the anion of the water-insoluble salt, said electrolyte layer being substantially free from a binder, and an ion selective layer, which is characterized in that the electrolyte layer comprises crystalline electrolyte having a mean crystal size of not more than 60 .mu.m. Processes preferably employable for the preparation of the ion selective electrode are also disclosed.

Abstract: An integral ion selective electrode for the analysis of a sodium ion comprising a support, an electroconductive metal layer such as a silver metal layer, a layer of a water-insoluble salt of said metal such as a silver chloride layer, an electrolyte layer which comprises an electrolyte salt of a sodium ion with the same anion as the anion of the water-insoluble salt, said electrolyte layer being substantially free from a binder, and an ion selective layer, which is characterized in that the electrolyte layer comprises crystalline electrolyte having mean size of not more than 8 .mu.m. Processes preferably employable for the preparation of the ion selective electrode are also disclosed.

Abstract: An ion selective electrode comprising a support having provided thereon, in sequence, a conductive layer and an ion selective layer, which is characterized by having at least one groove through the conductive layer and covering the surface of the groove with the ion selective layer is disclosed. Half cells or electrodes useful for the measurement of ionic activity of chlorine, sodium, potassium or, carbonate or hydrogen carbonate ions in blood or other aqueous sample liquids can be prepared in an extremely simple manner. The single ion selective electrode element comprising paired ion selective electrodes in accordance with the present invention are electrochemically equivalent. A process for forming the same is also disclosed.