# US 12,216,041 B2 · Method to detect diesel in fluid samples using partially dissolvable cuvettes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,041 B2 - Document ID: US12216041B2 - Status: Granted - Kind: B2 - Application number: 17/828,912 - Filed: 2022-05-31 - Published: 2023-11-30 - Granted: 2025-02-04 - Earliest claimed: 2022-05-31 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Amjad Felemban; Maha Nour; Hamad Al Saiari - Web page: https://patentgrep.com/patent/US12216041B2 ## CPC - 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 21/272: {for following a reaction, e.g. for determining photometrically a reaction rate (photometric cinetic analysis)} - G01N 21/3577: for analysing liquids, e.g. polluted water - G01N 33/28: Oils {, i.e. hydrocarbon liquids} (edible oils or edible fats G01N33/03) - G01N 2021/0321: {One time use cells, e.g. integrally moulded} - G01N 2021/0389: {Windows} - 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 method includes providing a cuvette containing a fluid sample having a first substance and emitting light from a light source through the cuvette containing the fluid sample for a duration of time. The cuvette is made of a material that at least partially dissolves in the presence of the first substance. Over the duration of time, the cuvette at least partially dissolves and an intensity of light that passes through the cuvette and the fluid sample changes at a rate. The method also includes receiving, by a light detector, the light that passed through the cuvette, measuring a change in intensity of the received light over the duration of time, and determining that the rate of change in intensity of the light over the duration of time is greater than a threshold rate of change. ## Claims ### Claim 1 A method for detecting a level of a substance in a fluid sample, the method comprising: providing a cuvette containing a fluid sample having a first substance, the cuvette comprising a material that is configured to at least partially dissolve in the presence of the first substance; emitting light from a light source through the cuvette containing the fluid sample for a duration of time, wherein the cuvette at least partially dissolves over the duration of time such that an intensity of light that passes through the cuvette and the fluid sample changes at a rate over the duration of time; receiving, by a light detector of the system, the light that passed through the cuvette and the fluid sample; measuring a change in intensity of the received light over the duration of time; determining if the rate of change in intensity of the light over the duration of time is greater than a threshold rate of change; and outputting, in response to the determination, a signal indicating that the fluid sample includes the first substance. ### Claim 2 (depends on 1) The method according to claim 1, wherein the first substance is an aromatic compound. ### Claim 3 (depends on 2) The method according to claim 2, wherein the aromatic compound is diesel. ### Claim 4 (depends on 2) The method according to claim 2, wherein the aromatic compound is—gasoline or lubrication oils. ### Claim 5 (depends on 1) The method according to claim 1, wherein the fluid sample is a refined petroleum product. ### Claim 6 (depends on 1) The method according to claim 1, wherein the material is a first material and wherein the cuvette comprises a second material, different from the first material. ### Claim 7 (depends on 6) The method according to claim 6, wherein the cuvette comprises sidewalls having a first layer defining a cavity and a second layer, wherein the sample fluid is disposed in the cavity, wherein the first layer comprises the first material and the first material comprises cyclic olefin polymer (COP), and wherein the second layer comprises the second material. ### Claim 8 (depends on 7) The method according to claim 7, wherein the first layer is arranged between the cavity and the second layer. ### Claim 9 (depends on 6) The method according to claim 6, wherein the second material is glass or quartz. ### Claim 10 (depends on 1) The method according to claim 1, wherein the threshold rate of change is zero. ### Claim 11 (depends on 6) The method according to claim 6, wherein the first material of the cuvette is COP. ### Claim 12 (depends on 1) The method according to claim 1, wherein the threshold rate of change is greater than zero. ### Claim 13 (depends on 1) The method according to claim 1, further comprising determining a level of a first substance in the fluid sample based on the rate of change in intensity of the light over the duration of time. ### Claim 14 (depends on 13) The method according to claim 13, wherein the rate of change in intensity of the light over the duration of time is proportional to the level of the first substance in the fluid sample. ### Claim 15 A method for detecting a level of diesel in a fluid sample, the method comprising: emitting, from a light source of a system, light through a cyclic olefin polymer (COP) cuvette containing the fluid sample, wherein COP of the cuvette is at least partially dissolvable by diesel; receiving, by a light detector of the system, the light; measuring an intensity of the received light over a duration of time; and determining, by a computer sub-system of the system, a level of diesel in the fluid sample based on the measured intensity of the received light over the duration of time. ### Claim 16 (depends on 15) The method according to claim 15, wherein determining a level of the diesel in the fluid sample based on the measured intensity over the duration of time comprises: calculating a rate of change of the intensity of the received light over the duration of time. ### Claim 17 (depends on 15) The method according to claim 15, wherein determining the level of the diesel in the fluid sample based on the measured intensity over the duration of time comprises: determining a presence of the diesel based on the measured intensity of the received light over the duration of time. ### Claim 18 (depends on 17) The method according to claim 17, wherein determining the presence of the diesel based on the measured intensity of the set of received light over the duration of time comprises: calculating a measured rate of change of the measured intensity of the received light over the duration of time. ### Claim 19 (depends on 18) The method according to claim 18, wherein a positive measured rate of change indicates the presence of the diesel. ### Claim 20 (depends on 18) The method according to claim 18, wherein a zero or negative measured rate of change indicates the absence of the diesel.