# US 2014/0192350 A1 · Flow Cells For Differential Refractive Index Detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192350 A1 - Document ID: US20140192350A1 - Status: Published application - Kind: A1 - Application number: 14/238,045 - Filed: 2012-08-16 - Published: 2014-07-10 - Earliest claimed: 2011-08-16 - Assignees: Waters Technologies Corporation - Inventors: Anthony C. Jeannotte - Web page: https://patentgrep.com/patent/US20140192350A1 ## CPC - G01N 21/05: Flow-through cuvettes (G01N21/09 takes precedence; handling fluid samples G01N1/10) - G01N 21/0303: {Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment (G01N21/031 - G01N21/15 take precedence)} - G01N 21/4133: {Refractometers, e.g. differential} - G01N 2021/0346: {Capillary cells; Microcells} - G01N 2021/0389: {Windows} - G01N 2021/4146: {Differential cell arrangements} - G01N 2021/4153: {Measuring the deflection of light in refractometers} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A flow cell for differential refractive index detection. The flow cell includes a transparent body that extends from a first end to a second end along a longitudinal axis. The transparent body defines a sample prism chamber and reference prism chamber. The sample prism chamber is configured to allow fluid flow between the first and second ends of the transparent body along the longitudinal axis. The reference prism chamber is configured to receive a reference fluid. The sample and reference prism chambers each include a grating comprising a plurality of grooves extending along the longitudinal axis in the direction of fluid flow. ## Claims ### Claim 1 A flow cell for differential refractive index detection, the flow cell comprising: a transparent body extending from a first end to a second end along a longitudinal axis, the transparent body defining: a sample prism chamber configured to allow fluid flow between the first and second ends of the transparent body along the longitudinal axis; and a reference prism chamber configured to receive a reference fluid; wherein the sample and reference prism chambers each comprise a grating comprising a plurality of grooves extending along the longitudinal axis in the direction of fluid flow. ### Claim 2 (depends on 1) The flow cell of claim 1, wherein the grating is an echelle grating. ### Claim 3 (depends on 1) The flow cell of claim 1, wherein transparent body includes first and second outer optical surfaces with the sample and reference prism chambers being disposed therebetween, and wherein the gratings are arranged parallel to each other and at an angle relative to the first and second outer optical surfaces. ### Claim 4 (depends on 1) The flow cell of claim 1, wherein the transparent body comprises a transparent partition wall separating the sample and reference prism chambers, the partition wall comprising a first smooth surface defining a boundary of the sample prism chamber and a second smooth surface, opposite the first smooth surface, defining a boundary of the reference prism chamber. ### Claim 5 (depends on 4) The flow cell of claim 4, wherein the transparent body includes first and second outer optical surfaces with the sample and reference prism chambers being disposed therebetween, and wherein the smooth surfaces of the transparent partition wall are arranged parallel to the gratings and at an angle relative to the first and second outer optical surfaces. ### Claim 6 (depends on 1) The flow cell of claim 1, wherein the gratings provide the prism chambers with the same optical edge length as chambers with triangular cross-sections while also providing the prism chambers with a comparatively smaller cross-sectional area. ### Claim 7 (depends on 6) The flow cell of claim 6, wherein the gratings provide the prism chambers with a cross-sectional area that is four (4) times smaller than chambers having triangular cross-sections with the same optical edge lengths as the prism chambers. ### Claim 8 (depends on 1) The flow cell of claim 1, wherein the transparent body is formed, at least in part, of silica ### Claim 9 (depends on 1) The flow cell of claim 1, wherein the transparent body is formed, at least in part, of an optical grade transparent polymer. ### Claim 10 (depends on 9) The flow cell of claim 9, wherein the optical grade transparent polymer is selected from the group consisting of polycarbonate, acrylics, and cyclo-olefin polymers. ### Claim 11 (depends on 1) The flow cell of claim 1, further comprising a protective surface layer on surfaces of the transparent body defining the sample and reference chambers, wherein the protective surface layer is resistant to chromatography mobile phase. ### Claim 12 A flow cell for differential refractive index detection, the flow cell comprising: a transparent body extending from a first end to a second end along a longitudinal axis, the transparent body defining: a first prism chamber configured to allow fluid flow between the first and second ends of the transparent body along the longitudinal axis; and a second prism chamber; wherein the first prism chamber comprises a grating comprising a plurality of grooves extending along the longitudinal axis in the direction of fluid flow. ### Claim 13 (depends on 12) The flow cell of claim 12, wherein the grating is an echelle grating. ### Claim 14 (depends on 12) The flow cell of claim 12, wherein transparent body includes first and second outer optical surfaces with the first and second prism chambers being disposed therebetween, and wherein the grating is arranged at an angle relative to the first and second outer optical surfaces. ### Claim 15 (depends on 14) The flow cell of claim 14, wherein the grating is arranged at an angle of about 5 degrees to about 85 degrees relative to the first and second outer optical surfaces. ### Claim 16 (depends on 15) The flow cell of claim 15, wherein the grating is arranged at an angle of about 45 degrees relative to the first and second outer optical surfaces. ### Claim 17 (depends on 12) The flow cell of claim 12, wherein the transparent body comprises a transparent partition wall separating the sample and reference prism chambers, the partition wall comprising a first smooth surface defining a boundary of the sample prism chamber and a second smooth surface, opposite the first smooth surface, defining a boundary of the reference prism chamber. ### Claim 18 (depends on 17) The flow cell of claim 17, wherein the transparent body includes first and second outer optical surfaces with the first and second prism chambers being disposed therebetween, and wherein the smooth surfaces of the transparent partition wall are arranged parallel to the grating and at an angle relative to the first and second outer optical surfaces. ### Claim 19 (depends on 18) The flow cell of claim 18, wherein the transparent body is arranged at an angle of about 5 degrees and about 85 degrees relative to the first and second outer optical surfaces. ### Claim 20 (depends on 19) The flow cell of claim 19, wherein the transparent body is arranged at an angle of about 45 degrees relative to the first and second outer optical surfaces. ### Claim 21 (depends on 1) The flow cell of claim 1, wherein the grating provides the sample prism chamber with the same optical edge length as a chamber with a triangular cross-section while also providing the prism chambers with a comparatively smaller cross-sectional area. ### Claim 22 (depends on 21) The flow cell of claim 21, wherein the grating provides the first prism chamber with a cross-sectional area that is four (4) times smaller than a chamber having a triangular cross-section with the same optical edge length as the first prism chamber. ### Claim 23 (depends on 12) The flow cell of claim 12, wherein the transparent body is formed of silica ### Claim 24 (depends on 12) The flow cell of claim 12, wherein the transparent body is formed of an optical grade transparent polymer. ### Claim 25 (depends on 24) The flow cell of claim 24, wherein the optical grade transparent polymer is selected from the group consisting of polycarbonate and cyclo-olefin polymers. ### Claim 26 (depends on 1) The flow cell of claim 1, wherein the diffracting grating comprises a protective surface layer. ### Claim 27 A method comprising: directing an optical beam through a flow cell containing sample and reference prism chamber, conveying a fluid flow through the sample prism chamber; detecting presence of an analyte in the fluid flow based on a detected deflection of the optical beam, wherein the sample prism chamber includes a grating comprising a plurality of grooves extending parallel to the direction of the fluid flow. ### Claim 28 (depends on 27) The method of claim 27, comprising detecting deflection of the optical beam with one or more detectors. ### Claim 29 (depends on 27) The method of claim 27, wherein the conveyed fluid flow comprises eluent from a separation device. ### Claim 30 A method comprising: molding an optical grade transparent polymer to form at lest part of a transparent body for a flow cell, the transparent body defining: a sample prism chamber configured to allow fluid flow through the transparent body and comprising a grating; and a reference prism chamber configured to receive a reference fluid; and depositing a protective surface layer on surfaces of the transparent body to make the sample and reference chambers resistant to fluids that are to be contained within sample and reference chambers.