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USPTO Application 18/285,431, All 15 Claims Rejected

Lead Test Patent Record

A complete examination history of the Lumetallix patent application for methylammonium bromide lead detection, and the prior art that preceded it by years.

Application Status

U.S. Patent Application No. 18/285,431 was filed October 3, 2023 by Helmbrecht et al. and published as US 2024/0183786 A1. On March 19, 2026, USPTO Examiner John McGuirk issued a Non-Final Office Action rejecting all 15 claims. Notification date: March 26, 2026.

Application No.
18/285,431
Publication
US 2024/0183786 A1
Filed
October 3, 2023
Examiner / Art Unit
John McGuirk / 1798
Office Action
Non-Final, Mar 26, 2026
Claims Rejected
All 15 of 15

What the Application Attempts to Claim

The application seeks to patent a method for detecting lead using methylammonium bromide (MABr). When MABr contacts lead ions (Pb²⁺), it forms CH₃NH₃PbBr₃ perovskite quantum dots that fluoresce bright green under 365 nm ultraviolet light. The inventors attempt to claim this chemistry applied to specific surfaces: painted china, ceramics, toys, and "electronic (waste) products."

The patent does not claim the chemistry itself, it claims the act of applying already-published chemistry to particular substrates. The USPTO examiner found this insufficient for patentability.

Two Independent Grounds for Rejection, Both Applied to All 15 Claims

35 U.S.C. § 102 / § 103, Anticipated by and Obvious Over Prior Art All 15 claims anticipated by or obvious over Yan et al. (2019), a peer-reviewed publication in Scientific Reports (Nature Research) demonstrating the identical MABr + Pb²⁺ → green perovskite chemistry on paper test strips, filed four years before this application.
35 U.S.C. § 112(b), Indefiniteness All 15 claims also rejected as indefinite. "Waste" is legally unclear. "Electronic (waste) products" is ambiguous. "e.g." in claim 9 renders the scope indeterminate. "The sample" in claims 11 and 14 lacks antecedent basis in the claim language.

Prior Art: The Science That Preceded This Application

A Third-Party Preissuance Submission under 37 CFR § 1.290 was filed by attorneys at Hovey Williams LLP, presenting eight prior art documents that establish the MABr lead-detection method was known, published, and practiced years before this application was filed. The USPTO examiner relied on this record.

⭐ Primary Prior Art, Anticipates All Independent Claims

Yan et al. (2019), Scientific Reports, Nature Research

"Determination of lead(II) via methylammonium lead bromide perovskite quantum dots formed from methylammonium bromide"

Published in 2019. Yan's team demonstrated:

  • MABr reacts with Pb²⁺ in situ → CH₃NH₃PbBr₃ perovskite quantum dots
  • Bright green fluorescence under 365 nm UV light
  • Detection on paper test strips (solid substrate), Figure S7 shows bright green "BJTU" letter patterns
  • Detection limit: 1 ng total lead; 0.05 ng/mm²
  • Lead carbonate substrate, directly analogous to lead paint pigment

The examiner mapped every element of claims 1–10 to Yan's disclosures. The identical reagent, the identical fluorescent readout, on a solid substrate. Specifying "painted china" instead of "paper strips" is an obvious modification, not a new invention.

Third-Party Preissuance Submission

Filed under 37 CFR § 1.290 · Hovey Williams LLP · Crissa A. Seymour Cook

Eight documents submitted to the USPTO record before examination, all now permanently part of the prosecution history:

  • 1
    Yan et al. (2019), Sci. Reports. MABr + Pb²⁺ → CH₃NH₃PbBr₃ perovskite, bright green fluorescence, 1 ng LOD on paper strips.
  • 2
    Yan et al. Supplementary Information (2019), Fig. S7: bright green "BJTU" letter patterns on paper at 365 nm UV, identical to claimed method.
  • 3
    Wang et al. (2020), MABr detecting sulfhydryl-bound (chelated) lead via MAPbBr₃ perovskite. Method works even on the most tightly bound lead forms.
  • 4
    McKnight (1989), Foundational lead carbonate chemistry relevant to paint pigment detection.
  • 5
    Millipore Sigma MABr Product Data, Commercial availability of methylammonium bromide as a known laboratory reagent.
  • 6
    Holtus et al. (2018), Nature Chemistry. Shape-preserving transformation of carbonate minerals into lead halide perovskites. Establishes lead carbonate → lead perovskite conversion mechanism.
  • 7
    Holtus et al. Supplementary Information (2018), Extended data on carbonate-to-perovskite transformation.
  • 8
    Zhang et al. (2017), Additional perovskite lead chemistry prior art.

The Examiner's Findings

Examiner McGuirk found that Yan 2019 anticipated all independent claims (1–10) and that the dependent claims (11–15) were obvious in light of Yan and additional prior art. His analysis mapped each claim element to the published record:

"Claims 1–15 are rejected under 35 U.S.C. § 103 as being unpatentable over Yan (2019)." , USPTO Non-Final Office Action, Application 18/285,431, March 19, 2026
Claims § 112(b) Indefiniteness § 102 / § 103 Prior Art Primary Reference
1 – 10 Rejected Rejected Yan et al. 2019 (anticipation)
11 – 15 Rejected Rejected Yan et al. 2019 (obviousness)

Specific indefiniteness issues: (1) "waste", unclear meaning; (2) "electronic (waste) products", ambiguous scope; (3) "e.g." in claim 9, renders claim indeterminate; (4) "the sample" in claims 11 and 14, no antecedent basis established in the claim body.

Why This Patent Was Always Flawed

The core error in this application is the assumption that applying a known chemical method to new substrates constitutes a patentable invention. It does not, and the prior art record makes that unmistakably clear.

By 2023 when this application was filed, MABr-based lead detection had already been demonstrated on:

  • Paper test strips, Yan et al. 2019 (the primary rejection reference)
  • Lead carbonate, the dominant pigment in lead paint, Holtus 2018 + Yan 2019
  • Sulfhydryl-bound (chelated) lead, Wang et al. 2020, the most chemically resistant lead form
  • Carbonate mineral surfaces, Holtus et al. 2018, Nature Chemistry
  • Quantities as small as 1 ng and 0.05 ng/mm², far below consumer safety thresholds

Specifying "painted china," "ceramic objects," "toys," or "e-waste" as the substrate does not distinguish a new invention from this body of work. Any practitioner familiar with the field would find this obvious.

Independent voices, including those familiar with the published literature at the time of the application's development, raised these patentability concerns before and during prosecution. The USPTO examination confirmed them.

Status as of April 2026

All 15 claims rejected. The prior art record established by the Third-Party Submission is now permanent, any amended claims must distinguish from Yan 2019, Wang 2020, Holtus 2018, and five additional references. FluoroSpec's method is based on the same publicly available, pre-existing chemistry.

Cited Documents

  • USPTO Application 18/285,431, Non-Final Office Action, March 19, 2026
  • US 2024/0183786 A1, Published Patent Application
  • Third-Party Preissuance Submission, 37 CFR § 1.290 (Hovey Williams LLP, Crissa A. Seymour Cook)
  • Yan, D. et al. "Determination of lead(II) via methylammonium lead bromide perovskite quantum dots formed from methylammonium bromide." Sci. Rep. 9, 16875 (2019). doi:10.1038/s41598-019-53297-0
  • Holtus, T. et al. "Shape-preserving transformation of carbonate minerals into lead halide perovskites." Nature Chem. 10, 740–745 (2018). doi:10.1038/s41557-018-0064-1
  • Wang et al. (2020), Sulfhydryl-bound lead detection via MAPbBr₃ perovskite

This page is maintained by FluoroSpec and reflects publicly available USPTO prosecution records. All claim numbers, rejection codes, and examiner citations are drawn directly from the official office action.