Abstract: A clamping device for controlling liquid flow in a length of flexible tubing; the device includes a generally planar support having a keyhole, an annular flexible sleeve seated in the keyhole for receiving the tubing in an orientation generally perpendicular to the planar support, and a mechanism for moving the flexible sleeve between the larger side of the keyhole and the smaller side of the keyhole to cause pinching of the tubing to control liquid flow.

Abstract: An electrode for determining the lithium content of a liquid sample to be tested, has a membrane containing a lithium ion selective compound and a plasticizer, the improvement wherein the plasticizer is a liquid, lipophilic dialkyl phthalate compound or a liquid phenyl phenyl ether compound that has a strong electron withdrawing group at an ortho position on one of the phenyl rings. The ion selective compound has the formula: ##STR1## wherein A is an alkyl group having between 8 and 16 carbon atoms, B is an alkyl group having between 1 and 4 carbon atoms, and each C and D is, independently, a hydrogen atom or an alkyl group having between 1 and 16 carbon atoms, provided that both C and D are not alkyl groups having greater than 4 carbon atoms.

Abstract: An electrode assembly for polarographic assay of glucose in solution having a laminated membrane, the outer membrane being from 1 to 20 .mu.m thick and having a pore size of 10 to 125 .ANG., the inner membrane having a thickness of 2 to 4 .mu.m, and bonded to the outer membrane with immobilized glucose oxidase. Rapid assays are carried out by measuring the current difference before equilibrium is attained and at least 5 seconds after initial contact of sample with the outer membrane.

Abstract: A releasing reagent for releasing, as ionized calcium, protein-bound calcium in a biological sample for measurement of the ionized calcium, together with any ionized calcium originally present in the sample, using a calcium ion specific electrode, the releasing reagent including monochlorocoacetate salt, formate salt, and formic acid, in concentrations sufficient to render the pH of the sample, when mixed with the reagent, in the range of 4.0 to 5.5. Also disclosed is a method of measuring calcium in a liquid sample using such a releasing reagent.

Abstract: In an electrode for determining the potassium ion content of a liquid sample to be tested, the electrode including a membrane having incorporated therein an ion selective component, the improvement in which the ion specific component is a compound of the formula: ##STR1## wherein each R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, and R.sub.8 is hydrogen or an alkyl group containing between one and about 20 carbon atoms, p is 0 or 1, n is one or more, and, each s and r, independently, is 1, 2, or 3, provided that, when p is 1, n is 8 or more.

Abstract: An electrode assembly comprising an organic plastic sample flow-through tube, a portion of the wall of which comprises a membrane, the membrane comprising a matrix of an organic plastic material containing a non-volatile solvent-plasticizer and an ion exchange material dissolved in the solvent plasticizer, the membrane chemically bonded to and integral with said tube. The method of forming the membrane to the tube comprises dissolving the matrix material, the ion exchange material and the non-volatile solvent plasticizer in a volatile solvent, placing the resulting solution on a surface and evaporating the volatile solvent to form the membrane, contacting an edge of the tube to the membrane material, contacting the tube edge with said volatile solvent and allowing the solvent to evaporate.

Abstract: An electrode assembly comprising an organic plastic sample flow-through tube, a portion of the wall of which comprises a membrane, the membrane comprising a matrix of an organic plastic material containing a non-volatile solvent-plasticizer and an ion exchange material dissolved in the solvent plasticizer, the membrane chemically bonded to and integral with said tube. The method of forming the membrane to the tube comprises dissolving the matrix material, the ion exchange material and the non-volatile plasticizer in a volatile solvent, placing the resulting solution on a surface and evaporating the volatile solvent to form the membrane, contacting an edge of the tube to the membrane material, contacting the tube edge with said volatile solvent and allowing the solvent to evaporate.