Gary Clayton Lang

US Patent:

51399563, Aug 18, 1992

Filed:

Mar 4, 1991

Appl. No.:

7/663791

Inventors:

Karl G. Schick - Milwaukee WI
Paul M. Karges - Milwaukee WI
Gary A. Lang - Brookfield WI
David A. Uhen - Palmyra WI

Assignee:

FIAtron-Eppendorf, Inc. - Madison WI

International Classification:

G01N 2101
G01N 2175
G01N 3122

US Classification:

436 52

Abstract:

The peroxide content of a non-aqueous medium is measured by a system including separate supplies for two carrier solutions, a first one containing an acid for acidifying the sample and the second containing an iodide compound for reacting with the peroxide(s) in the sample and producing a free iodine ion, such as I. sub. 3. sup. -, and a flow-through detector, such as a colorimetric device. The sample and first carrier solution streams are controlled by a sample injection valve which is movable between a load position wherein the sample stream is routed to a sample waste collector via a sample loop and the first carrier solution stream passes through a first carrier solution conduit and is combined with a stream the second carrier solution prior to passing through the detector and a measure position wherein a slug of the sample is introduced into the first carrier solution conduit, mixed with the first carrier solution and combined with the second carrier solution prior to passing through the detector. The peroxide(s) in the sample reacts with the iodide compound in the second carrier solution to produce I. sub. 3. sup. - which is measured by the detector.

US Patent:

51961695, Mar 23, 1993

Filed:

Oct 2, 1991

Appl. No.:

7/771318

Inventors:

Karl G. Schick - Milwaukee WI
Paul M. Karges - Milwaukee WI
Gary A. Lang - Brookfield WI
David A. Uhen - Palmyra WI

Assignee:

Eppendorf North America, Inc. - Madison WI

International Classification:

G01N 3303
G01N 3508

US Classification:

422 81

Abstract:

The free fatty acid content of an edible oil is measured by a system including a supply of a carrier solution containing an organic solvent for dissolving the oil and a color indicating reagent and an oil sample supply connected to a flow-through colorimetric detector via a sample injection valve. The sample injection valve is movable between a load position wherein a sample stream of the oil is routed to a sample waste collector via a sample loop and a stream of the carrier solution passes through the detector via a carrier solution conduit and a measure position wherein a slug of the oil in the sample loop is introduced into the carrier solution conduit and mixed with the carrier solution prior to passing through the detector. The free fatty acid in the oil reacts with the color indicating reagent in the carrier solution to produce a color of an intensity indicative of the free fatty acid content which is measured by the detector. The system also includes a selector valve manifold including up to three different calibration solutions which can be selectively introduced.