Prosecution Insights
Last updated: April 19, 2026
Application No. 18/151,161

POTASSIUM MALEATE BUFFER FOR FREE CHLORINE ANALYSIS

Non-Final OA §101§103
Filed
Jan 06, 2023
Examiner
ALABI, OYELEYE A
Art Unit
1797
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Hach Company
OA Round
3 (Non-Final)
86%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 86% — above average
86%
Career Allow Rate
227 granted / 263 resolved
+21.3% vs TC avg
Strong +22% interview lift
Without
With
+21.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
31 currently pending
Career history
294
Total Applications
across all art units

Statute-Specific Performance

§101
5.7%
-34.3% vs TC avg
§103
44.5%
+4.5% vs TC avg
§102
25.5%
-14.5% vs TC avg
§112
20.2%
-19.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 263 resolved cases

Office Action

§101 §103
DETAILED ACTION In application filed on 01/06/2023, Claims 1 and 3-14 are pending. The claim set submitted on 01/15/2026 is considered because this is the most recent claim set. Claims 1 and 3-14 are considered in the current office action. Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Information Disclosure Statement The information disclosure statement (IDS) submitted on 06/17/2024 are in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner. Claim Rejections - 35 USC § 101 35 U.S.C. 101 reads as follows: Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title. Claims 7-14 are rejected under 35 U.S.C. 101 because the claimed invention is directed to an abstract idea without significantly more. The claims have been analyzed for eligibility in accordance with their broadest reasonable interpretation. All claims are directed to statutory categories, i.e., a method (Claims 7-14) (Step 1: YES). Analysis: Claim 7: Ineligible. Step 1: The claim recites a series of steps or acts, including “measuring a concentration of free chlorine in a water system”. Thus, the claim is directed to a method, which is one of the statutory categories of invention (Step 1: YES). Step 2A Prong 1: Claim 18 recites “determining a concentration of the free chlorine in the water system based on the measured light absorbance “(math or mental step)”. Therefore, the claim is directed towards an abstract idea, and more specifically to the abstract idea group of a math or mental process since claim 7 relates to using a math or mental process to “determine a concentration of the free chlorine in the water system based on the measured light absorbance” (Step 2A, Prong 1: YES). Step 2A, Prong 2: This judicial exception is not integrated into a practical application. Once the determination is done, No further action takes place, much less a particular practical application. (Step 2A, Prong 2: NO). In addition, the steps of,” adding an indicator…, “measuring a light absorbance; and “wherein a concentration of the potassium maleate…” are recited at a high level of generality that that they amount to mere data gathering (insignificant extra-solution activity). See MPEP 2106.05(g). Step 2B: Furthermore, the courts have found that limitations adding insignificant extrasolution activity to the judicial exception, such as mere data gathering in conjunction with a law of nature or abstract idea, are limitations found not to be enough to qualify as ‘significantly more’ when recited in a claim with a judicial exception (see the 2014 Interim Guidance on Patent Subject Matter Eligibility of the Federal Register dated December 16, 2014; and MPEP 2106.05(I)(A)). Note that mere data gathering is not significantly more than the abstract idea. See MPEP 2106.05(g). Here, there are no additional elements which are significantly more than the abstract idea in independent Claim 7. The limitation of “adding an indicator and a buffer including potassium maleate to a water sample collected from the water system”; “measuring a light absorbance of the water sample after the indicator and the buffer have been added to the water sample”; and “wherein a concentration of the potassium maleate in the buffer is in a range of 2 to 4 mol/liter (M)” from the background section of the claim appear well-understood, routine, and conventional (WURC) in the field of water quality analysis, as evidenced by Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024); in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995). further in view of Morin et al. (US3822115A). Also See the instruction manual for additional teachings: PCA 310, PCA 320, PCA 330 Chlorine, pH, Temperature, ORP Analyzers (https://www.instrumart.com/assets/manpca_310_320_330.pdf?srsltid=AfmBOoo6nItiVtYElk8dnn-46kh7v85dzKcwiW21ZnN8OVUHZ9JiYdA0 (Step 2B: NO). Therefore, Claim 7 is ineligible. Moreover, Claims 8-14 are rejected by virtue of their dependency on Claim 7. Claims 8-14: Ineligible. Step 2A, Prong One and Prong Two: Claims 8-14 further define the data gathering steps which appear to be generic and WURC. Step 2B: The claims do not recite any elements which are significantly more. Therefore, Claims 8-14 are ineligible. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claims 1, 3-9 and 13-14 are rejected under 35 U.S.C. 103 as being unpatentable over Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024) in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995).) in view of Morin et al. (US3822115A). Regarding Claim 1, Kurani teaches a kit comprising: a buffer (Col. 12, line 52…buffer solutions; 1M HEPES buffer]); and an indicator for measuring free chlorine in water (See Table 1…Free Chlorine DPD reagent; Col. 22, lines 8-10…The reagent can be added and mixed with the buffer and water 365. In an embodiment, the reagent can be free chlorine DPD). Kurani does not teach a buffer including potassium maleate. In the analogous art of the current technology of Chlorine analysis for water and waste water, Harp teaches a buffer including maleate (See Page 26…the free chlorine buffer reagent is a maleate-type buffer). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the kit of Kurani to include maleate, as taught by Harp for the benefit of having a buffer for the analysis of free chorine in the CL17 Chlorine Analyzer (Harp, Page 26, Fig. 5.2), allowing for the facilitation of online automated testing to ensure that that residual chlorine be monitored continuously on distributed water for systems serving more than 3300 persons (Harp, Section 5c.; Page 26). The combination of Kurani and Harp does not explicitly teach a buffer including potassium maleate. In the analogous art of using an acidic buffer system for the determination of an analyte in an aqueous solution, Morin teaches the use of a buffer including potassium maleate (See Col. 2, lines 70-73 Col. 3, lines 1-4…the term acid buffer, as used herein, means that a salt thereof is included. An example is maleic acid buffer which includes maleic acid and a salt or ester thereof, e.g., sodium maleate, potassium maleate, barium maleate and lithium maleate; Also See Col. 2, lines 59-60…Examples of useful acidic buffers are maleic acid (preferred)…). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the kit of the combination of Kurani and Harp to include the use of a buffer including potassium maleate, as taught by Morin for the benefit of using a suitable acidic buffer system, as, for example, maleic acid…which have a suitable pK for buffering in the pH range of 3 to 6.5, preferably at 5.5; (Morin, Col. 2, lines 10-11)…a maleic acid buffer or other suitable acidic buffer. The reagent has a pH in the range of 3 to 6.5, preferably at pH 5.5 (Morin, Col. 2, lines 19-21), allowing for the provision of a method for uric acid determination that is colorimetric in the visible range (Morin, Col.1, lines 46-60). The combination of Kurani, Harp and Morin does not teach that a concentration of the potassium maleate in the buffer is in a range of 2 to 4 mol/liter (M). However, MPEP § 2144.05, Part II, Subpart B holds that a particular parameter that is recognized as a result effective variable (“a variable that achieves a recognized result”) would be one, but not the only motivation for a person of ordinary skill in the art to experiment to reach another workable product or process. In the preparation of buffers as reagents in the laboratory, the selection of optimal experimental conditions including buffer concentration (Molarity) affects a solution's buffering capacity, allowing it to resist pH changes more effectively by consuming larger amounts of added acids or bases. Thus, a concentration of the potassium maleate in the buffer is in a range of 2 to 4 mol/liter (M) is a result effective variable. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to prepare a concentration of the potassium maleate in the buffer that is in a range of 2 to 4 mol/liter (M) for the benefit of providing a buffer with an optimal buffering capacity in a kit for monitoring free chorine in water, which facilitates a monitoring system that will help owners properly maintain their pools and spas so that they are always in proper pH balance to save money, conserve water and prevent unnecessary maintenance (Kurani, Col.1, lines 45-50). Regarding Claim 3, the kit of claim 1 is obvious over Kurani in view of Harp and further in view of Morin. Kurani teaches that the buffer (Col. 12, line 52…buffer solutions) includes an aqueous solution of the buffer (See Col. 22, lines 1-10…the buffer can be free chlorine phosphate buffer with a volume of 5% v/v; See Col. 22, lines 24-25…the buffer can then be added to the flowcell and mixed with the water). Kurani does not teach a buffer including potassium maleate. The combination of Kurani and Harp does not explicitly teach a buffer including potassium maleate. In the analogous art of using an acidic buffer system for the determination of an analyte in an aqueous solution, Morin teaches the use of a buffer including potassium maleate (See Col. 2, lines 70-73 Col. 3, lines 1-4…the term acid buffer, as used herein, means that a salt thereof is included. An example is maleic acid buffer which includes maleic acid and a salt or ester thereof, e.g., sodium maleate, potassium maleate, barium maleate and lithium maleate; Also See Col. 2, lines 59-60…Examples of useful acidic buffers are maleic acid (preferred)…). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the kit of the combination of Kurani and Harp to include the use of a buffer including potassium maleate, as taught by Morin for the benefit of using a suitable acidic buffer system, as, for example, maleic acid…which have a suitable pK for buffering in the pH range of 3 to 6.5, preferably at 5.5; (Morin, Col. 2, lines 10-11)…a maleic acid buffer or other suitable acidic buffer. The reagent has a pH in the range of 3 to 6.5, preferably at pH 5.5 (Morin, Col. 2, lines 19-21), allowing for the provision of a method for uric acid determination that is colorimetric in the visible range (Morin, Col.1, lines 46-60). Regarding Claim 4, the kit of claim 3 is obvious over Kurani in view of Harp and further in view of Morin. The combination of Kurani, Harp and Morin does not teach that the potassium maleate is soluble in the aqueous solution at a temperature in a range of from 0°C to 35°C. In the analogous art of a method where potassium maleate was used in preparing enzyme formulations, Yun teaches that the potassium maleate is soluble in the aqueous solution (See Col.8, Claims 23-36…the resulting formulation in aqueous buffered form, where the buffer is a maleate; See Col. 2, lines 33-34…the buffer employed can be a maleate, in the form of the sodium or potassium…). Regarding the limitation “at a temperature in a range of from 0°C to 35°C”, Though Yun do not explicitly teach a temperature in a range of from 0°C to 35°C, Yun does teach this limitation using an overlapping range disclosure (See Col.7, lines 29-31…said conditions of the assay comprise incubation at a temperature between room temperature and 45° C). As a result, since the claimed limitation overlap the range disclosed by the prior art, a prima facie case of obviousness exists. Please see MPEP 2144.05 (I) and In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976) for further details. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Kurani to include that the potassium maleate is soluble in the aqueous solution at a temperature in a range of from 0°C to 35°C, as taught by Yun for the benefit of facilitating optimal conditions for the enzymatic and surfactant actions necessary for effectively clearing turbidity from the samples (Yun, Col. 7, lines 19-30), allowing for the clearing of turbidity of a sample, thereby facilitating it to be accurately photometrically assayed or analyzed (Yun, Col. 3, lines 28-30). Regarding Claim 5, the kit of claim 1 is obvious over Kurani in view of Harp and further in view of Morin. Kurani further teaches that the buffer (Col. 12, line 52…buffer solutions; Fig. 33…0.1M HEPES) has a pH in a range of 6.8 to 8.2 (See Fig. 33…a graph of pH measured vs. standard buffer solution...pH 6.8-8.2). Though Kurani does not explicitly teach that the buffer has a pH in a range of 7 to 8, Kurani does teach this limitation using an overlapping range disclosure (See Fig. 33…a graph of pH measured vs. standard buffer solution...pH 6.8-8.2). As a result, since the claimed limitation overlap the range disclosed by the prior art, a prima facie case of obviousness exists. Please see MPEP 2144.05 (I) and In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976) for further details. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Kurani and Yun to incorporate that the buffer has a pH in a range of 7 to 8, as taught by Kurani for the benefit of designating a specific range for accurate water pH measurements using light absorption techniques (Kurani, Col. 19, line 27-36), allowing for the provision of a device that monitors and maintains swimming pool chemistry (Kurani, Abstract). Regarding Claim 6, the kit of claim 1 is obvious over Kurani in view of Harp and further in view of Morin. Kurani further teaches that the indicator is N,N-diethyl-p-phenylenediamine (DPD) (See Col. 23, line 20-23…When DPD in either liquid form is added to a water sample, a pink color forms with an intensity proportional to the chlorine concentration (either free or total, depending on the step of the procedure, thereby teaching “indicator is N,N-diethyl-p-phenylenediamine (DPD)”). Regarding Claim 7, Kurani teaches a method of measuring a concentration of free chlorine in a water system (See Abstract…monitoring…free chlorine in water including a swimming pool), the method comprising: adding an indicator and a buffer (See Col. 18, lines 34-35, Step 2…Dispense the analyte detecting reagent, such as bromocresol green/methyl red blended indicator and any other reagent such as buffers, chlorine neutralizers) i to a water sample collected from the water system (See Col. 17, lines 31-32… water from pool; See Col. 16, lines 65-67…the body of water to be measured for instance a residential pool, commercial pool, agricultural water storage tank, or commercial fishery). Further see Kurani for the steps 1-4… Col.17, lines 63-Col. 18, lines 45). measuring a light absorbance of the water sample after the indicator and the buffer have been added to the water sample (See Col. 18, lines 45-49, Step 5…Take a light absorption reading of the mixture of reagents by illuminating the light source and measuring the transmitted through the water sample and reagent mixture with a light sensor); and determining a concentration of the free chlorine in the water system based on the measured light absorbance (See Col. 21, lines 43-56, Free Chlorine Test…The free chlorine and bromine are determined using the DPD (N, N Diethyl-I, 4 Phenylenediamine Sulfate) colorimetric method at near neutral pH. The blue and green absorption is measured in order to determine the chlorine or bromine concentration. FIG. 29 shows the linear region for the blue and green absorption response for CL2 ppm in the y-axis v. green and blue light absorption on the x-axis…). Kurani does not teach a buffer including potassium maleate. In the analogous art of the current technology of Chlorine analysis for water and waste water, Harp teaches a buffer including maleate (See Page 26…the free chlorine buffer reagent is a maleate-type buffer). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the kit of Kurani to include maleate, as taught by Harp for the benefit of having a buffer for the analysis of free chorine in the CL17 Chlorine Analyzer (Harp, Page 26, Fig. 5.2), allowing for the facilitation of online automated testing to ensure that that residual chlorine be monitored continuously on distributed water for systems serving more than 3300 persons (Harp, Section 5c.; Page 26). The combination of Kurani and Harp does not explicitly teach a buffer including potassium maleate. In the analogous art of using an acidic buffer system for the determination of an analyte in an aqueous solution, Morin teaches the use of a buffer including potassium maleate (See Col. 2, lines 70-73 Col. 3, lines 1-4…the term acid buffer, as used herein, means that a salt thereof is included. An example is maleic acid buffer which includes maleic acid and a salt or ester thereof, e.g., sodium maleate, potassium maleate, barium maleate and lithium maleate; Also See Col. 2, lines 59-60…Examples of useful acidic buffers are maleic acid (preferred)…). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the kit of the combination of Kurani and Harp to include the use of a buffer including potassium maleate, as taught by Morin for the benefit of using a suitable acidic buffer system, as, for example, maleic acid…which have a suitable pK for buffering in the pH range of 3 to 6.5, preferably at 5.5; (Morin, Col. 2, lines 10-11)…a maleic acid buffer or other suitable acidic buffer. The reagent has a pH in the range of 3 to 6.5, preferably at pH 5.5 (Morin, Col. 2, lines 19-21), allowing for the provision of a method for uric acid determination that is colorimetric in the visible range (Morin, Col.1, lines 46-60). The combination of Kurani, Harp and Morin does not teach that a concentration of the potassium maleate in the buffer is in a range of 2 to 4 mol/liter (M). However, MPEP § 2144.05, Part II, Subpart B holds that a particular parameter that is recognized as a result effective variable (“a variable that achieves a recognized result”) would be one, but not the only motivation for a person of ordinary skill in the art to experiment to reach another workable product or process. In the preparation of buffers as reagents in the laboratory, the selection of optimal experimental conditions including buffer concentration (Molarity) affects a solution's buffering capacity, allowing it to resist pH changes more effectively by consuming larger amounts of added acids or bases. Thus, a concentration of the potassium maleate in the buffer is in a range of 2 to 4 mol/liter (M) is a result effective variable. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to prepare a concentration of the potassium maleate in the buffer that is in a range of 2 to 4 mol/liter (M) for the benefit of providing a buffer with an optimal buffering capacity in a kit for monitoring free chorine in water, which facilitates a monitoring system that will help owners properly maintain their pools and spas so that they are always in proper pH balance to save money, conserve water and prevent unnecessary maintenance (Kurani, Col.1, lines 45-50). Regarding Claim 8, the method of Claim 7 is obvious over Kurani in view of Harp and further in view of Morin. Kurani further teaches that the water sample has a pH in a range of 4 to 10 before the indicator and the buffer are added (See Col. 5, lines 57-58…the optimum pH level for a pool can be between about 7.4 and 7.6; See Col. 20, lines 41-49… Water having a pH level of about 8.2 can have a 440 nm light absorption of about 0.2 and water having a pH level of about 6.8 can have a 440 nm light absorption of about 0.45…). Regarding Claim 9, the method of Claim 7 is obvious over Kurani in view of Harp and further in view of Morin. Kurani further teaches that the water sample has a pH in a range after the indicator “phenol red” and the buffer (water reagent mixture”; Also see Col. 18, step 3 where reagent include buffers) are added (See Col. 20, lines 18-20…A solution of phenol red is used as a pH indicator and the water reagent mixture can exhibit a gradual color transition from yellow to red over the pH range 6.8 to 8.2) Kurani does not explicitly teach that water sample has a pH in a range of 5.5-7. However, Kurani does teach this limitation using an overlapping range disclosure (See Col. 20, lines 18-20…A solution of phenol red is used as a pH indicator and the water reagent mixture can exhibit a gradual color transition from yellow to red over the pH range 6.8 to 8.2) As a result, since the claimed limitation overlap the range disclosed by the prior art, a prima facie case of obviousness exists. Please see MPEP 2144.05 (I) and In re Wertheim, 541 F.2d 257, 191USPQ 90 (CCPA 1976) for further details. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Kurani and Yun to incorporate that water sample has a pH in a range of 5.5-7, as taught by Kurani for the benefit of measuring absorbed wavelengths of the exhibited gradual color transition from yellow to red over the pH range 6.8 to 8.2 (Kurani, Col. 20, lines 7-20), allowing for the provision of a device that monitors and maintains swimming pool chemistry (Kurani, Abstract). Regarding Claim 13, the method of Claim 7 is obvious over Kurani in view of Harp and further in view of Morin. Kurani further teaches that the indicator is N,N-diethyl-p-phenylenediamine (DPD) (See Col. 23, line 20-23…When DPD in either liquid form is added to a water sample, a pink color forms with an intensity proportional to the chlorine concentration (either free or total, depending on the step of the procedure, thereby teaching “indicator is N,N-diethyl-p-phenylenediamine (DPD)”). Regarding Claim 14, the method of Claim 7 is obvious over Kurani in view of Harp and further in view of Morin. Kurani teaches that the light absorbance of the water sample is measured (See Col. 18, lines 45-49, Step 5…Take a light absorption reading of the mixture of reagents by illuminating the light source and measuring the transmitted through the water sample and reagent mixture with a light sensor) at a wavelength in a range of from 480 to 580 nm (See Col. 19, lines 14-15…In FIG. 32 a graph of light absorption at wavelengths of light between 375 nm and 580 nm is illustrated; See Col. 19, lines 19-21…n this example, at 560 nm wavelength, the 47.9 degree C. sample absorption can be 20 about 1.3 while the 4 degree C; See Col. 20, lines 30-31…the two wavelengths can be measured…Lines 37-38…the second wavelength can be 560 nm. Based upon the ratio's these measurements, the accuracy of the measured pH can be within 5%...) Claims 10 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024) in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995).) and further in view of Morin et al. (US3822115A) as applied to claim 7 above, and further in view of Chibata et al. (US4124636A). Regarding Claim 10, the method of Claim 7 is obvious over Kurani in view of Harp and further in view of Morin. The combination of Kurani, Harp and Morin does not teach that the buffer is produced by reacting potassium hydroxide with maleic acid. In the analogous art of a method of preparing monopotassium L-malate and its monohydrate, Chibata teaches that the buffer (See Abstract… An aqueous solution of L-malic acid and potassium ion) is produced by reacting potassium hydroxide (See Col. 3, lines 3-4…potassium hydroxide are suitable as the water-soluble potassium salt) with maleic acid (See Abstract…An aqueous solution of L-malic acid and potassium ion is prepared having a pH of no more than 6.8). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of the combination of Kurani, Harp and Morin to incorporate that the buffer is produced by reacting potassium hydroxide with maleic acid, as taught by Chibata for the benefit of initiating crystallization of a potassium salt of L-malic acid (Chibata, Abstract), allowing for the provision of a practical and economical method for preparing monopotassium L-malate monohydrate and its anhydrate in stable, non-hygroscopic forms (Chibata, Col. 2, lines 9-12). Regarding Claim 12, the method of Claim 7 is obvious over Kurani in view of Harp and further in view of Morin. The combination of Kurani, Harp and Morin does not explicitly teach that the buffer includes dipotassium maleate and monopotassium maleate. In the analogous art of a method of preparing monopotassium L-malate and its monohydrate, Chibata teaches that the buffer (See Abstract; Col.1, lines 50-54… An aqueous solution of L-malic acid and potassium ion) includes dipotassium maleate (See Col.1, lines 50-54…a malic acid salt contained in the solution exists substantially in the form of dipotassium L-malate at a pH higher than 6.8) and monopotassium maleate (See Col. 1, lines 57-60…crystals of monopotassium L-malate monohydrate …are obtained by cooling an aqueous solution of L-malic acid and potassium ion at a pH of 6.8 or less). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of the combination of Kurani, Harp and Morin incorporate that the buffer includes dipotassium maleate and monopotassium maleate, as taught by Chibata for the benefit of demonstrating that the aqueous solution of L-malic acid and potassium ion can contain both dipotassium L-malate at pH higher than 6.8 and monopotassium L-malate monohydrate at a pH of 6.8 or less (Chibata, See Col. 1, lines 50-60), allowing for the provision of a practical and economical method for preparing monopotassium L-malate monohydrate and its anhydrate in stable, non-hygroscopic forms (Chibata, Col. 2, lines 9-12). Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024) in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995).) and further in view of Morin et al. (US3822115A) further in view of Chibata et al. (US4124636A) as applied to claim 10 above, and further in view of Wojcieszak et al. ("Recent developments in maleic acid synthesis from bio-based chemicals." Sustainable Chemical Processes 3.1 (2015): 9). Regarding Claim 11, the method of Claim 10 is obvious over Kurani in view of Harp, further in view of Morin and further in view of Chibata. The combination of Kurani, Harp, Morin and Chibata does not teach that the maleic acid is produced by reacting maleic anhydride is reacted with water. In the analogous art of maleic acid synthesis from biomass-derived chemicals, Wojcieszak teaches that the maleic acid is produced by reacting maleic anhydride is reacted with water (See Page 2, Scheme 1…that mild hydrolysis of maleic anhydride (MAnh) leads to maleic acid). It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of the combination of Kurani, Harp, Morin and Chibata to incorporate that the maleic acid is produced by reacting maleic anhydride is reacted with water, as taught by Wojcieszak for the benefit of synthesizing maleic acid from biomass-derived chemicals over homogeneous or heterogeneous catalysts (See Wojcieszak, Abstract), allowing for the provision of a highly effective method to produce these dicarboxylic acids from biomass (See Wojcieszak, Page 2). Response to Arguments Applicant's arguments filed on 01/15/2026, with respect to the 35 U.S.C. §101 rejections on Claims 7-14 have been fully considered but they are not persuasive. Applicant asserts that under Step 2B of the patent eligibly analysis, the limitation of "adding an indicator and a buffer including potassium maleate to a water sample collected from the water system" is not a well-understood, routine, conventional activity. Accordingly, the claim, as a whole, is directed toward patent eligible subject matter. Further, Applicant asserts that the Office Action only points to the asserted references of the obviousness rejection and merely states the limitations "are well understood, routine, and conventional." See the Office Action at page 18. However, as described above, this conclusory and overly broad statement fails to establish whether the limitation is well-understood, routine, and conventional. Instead, at most, the Office Action is inappropriately trying to establish patent ineligibility by trying to establish obviousness. Yet, the MPEP 2106.05 clearly states that this is improper: "[L]ack of novelty under 35 U.S.C. 102 or obviousness under 35 U.S.C. 103 of a claimed invention does not necessarily indicate that additional elements are well-understood, routine, conventional elements." …the Office Action has failed to establish that the limitation at issue is are well understood, routine, and conventional, and has, therefore, failed to establish that the claims are directed toward ineligible subject matter. Accordingly, reconsideration and withdrawal of the rejection are requested. II. Rejections Under 35 U.S.C. §103 Applicant’s arguments with respect to claim 7 has been considered and Examiner respectfully disagrees. Examiner identifies the judicial exception as “determining a concentration of the free chlorine in the water system based on the measured light absorbance” and found that the additional elements do not integrate the exception into a practical application (Step 2A Prong Two) and do not amount to significantly more than the exception (Step 2B) because they are well-understood, routine and conventional activities in the field of water quality analysis (See 101 rejection Supra). In addition, these elements are claimed in a merely generic manner (e.g., at a high level of generality) or as insignificant extra-solution activity: See MPEP 2106.05(d), previously known to the industry. Examiner further submits that the prior art of record shows methods of measuring the concentration of free chlorine in a water system as disclosed by Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024) in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995).) in view of Morin et al. (US3822115A). Also See the instruction manual for additional teachings: PCA 310, PCA 320, PCA 330 Chlorine, pH, Temperature, ORP Analyzers (https://www.instrumart.com/assets/manpca_310_320_330.pdf?srsltid=AfmBOoo6nItiVtYElk8dnn-46kh7v85dzKcwiW21ZnN8OVUHZ9JiYdA0 As a result, the claims do not amount to significantly more that the judicial exception. The 101 rejection is maintained. Declaration under 37 CFR 1.132 The declaration under 37 CFR 1.132 filed 01/15/2026 is insufficient to overcome the rejection of claim 1 and Claims 3-14 based upon 35 U.S.C. §103 rejection on Claim 1 and Claim 7 as set forth in the last Office action because: The statements in the declaration consists primarily of the declarant’s [Douglas Royer] opinions and conclusory assertions rather than factual evidence. Examiner submits that MPEP 716.01(c) states that factual evidence is preferable to opinion testimony. Although opinion testimony is entitled to consideration and some weight so long as the opinion is not on the ultimate legal conclusion at issue….In re Chilowsky, 306 F.2d 908, 134 USPQ 515 (CCPA 1962) (expert opinion that an application meets the requirements of 35 U.S.C. 112 is not entitled to any weight; however, facts supporting a basis for deciding that the specification complies with 35 U.S.C. 112 are entitled to some weight), Accordingly, Examiner submits that the declaration is not given little or no probative weight and does not rebut the prima facie case on obvious on independent claims 1 and 7. Applicant’s arguments, see Page 7, filed 01/15/2026, with respect to the rejection(s) of claim(s) 1 and 3-14 under 35 U.S.C. §103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024) in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995).) in view of Morin et al. (US3822115A). Applicant asserts that the references fail to teach the claimed molarity, and one of ordinary skill in the art would not arrive at the claimed molarity based on the asserted references. Further, applicant contends that claim 1 has been amended to recite: "wherein a concentration of the potassium maleate in the buffer is in a range of 2 to 4 mol/liter (M)" and that the asserted references do not teach or suggest at least this claim feature. Applicant’s arguments with respect to amended claims 1 and 7 has been considered and Examiner respectfully disagrees. Examiner submits that the limitations of amended Claim 1 is taught as disclosed in the rejection of Claims 1 and 7 (Supra) by Kurani et al. (US10150680B1, submitted in IDS on 06/17/2024) in view of Harp ("Current Technology of Chlorine Analysis for water and wastewater, Technical information series-Booklet No. 17." Hach Company, USA (1995).) in view of Morin et al. (US3822115A). Examiner suggests to the Applicant to amend the claims and/or provide additional evidence addressing the Examiner’s position above. Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. PCA 310, PCA 320, PCA 330 Chlorine, pH, Temperature, ORP Analyzers (https://www.instrumart.com/assets/manpca_310_320_330.pdf?srsltid=AfmBOoo6nItiVtYElk8dnn-46kh7v85dzKcwiW21ZnN8OVUHZ9JiYdA0, downloaded on 02/27/2026): This instruction manual discloses: The Hanna PCA 310, PCA 320 and PCA 330 series of chlorine, pH, ORP and temperature analyzers are microprocessor controlled, process analyzers which continuously monitor a sample stream for chlorine content, pH, ORP and temperature values. The PCA 310-330 monitor the free chlorine or total chlorine in the 0 to 5 mg/L range depending on the factory settings and used reagents. In the DPD Colorimetric method, N, N-Diethyl-p-phenylene diamine indicator and a buffer are mixed with the sample. Any inquiry concerning this communication or earlier communications from the examiner should be directed to OYELEYE ALEXANDER ALABI whose telephone number is (571)272-1678. The examiner can normally be reached on M-F 7:30am-5:30pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Lyle Alexander can be reached on (571) 272-1254. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see https://ppair-my.uspto.gov/pair/PrivatePair. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /OYELEYE ALEXANDER ALABI/Examiner, Art Unit 1797
Read full office action

Prosecution Timeline

Jan 06, 2023
Application Filed
Aug 09, 2025
Non-Final Rejection — §101, §103
Sep 26, 2025
Response Filed
Oct 22, 2025
Final Rejection — §101, §103
Jan 15, 2026
Response after Non-Final Action
Jan 15, 2026
Request for Continued Examination
Jan 20, 2026
Response after Non-Final Action
Feb 28, 2026
Non-Final Rejection — §101, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
86%
Grant Probability
99%
With Interview (+21.9%)
2y 11m
Median Time to Grant
High
PTA Risk
Based on 263 resolved cases by this examiner. Grant probability derived from career allow rate.

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