{
  "abstract": "This paper reports a simple one-step colorimetric method for distinguishing l- and d-tryptophan based on the in situ formation of gold nanoparticles (AuNPs) in the presence of Cu²⁺. The tryptophan enantiomers act as both reducing and stabilizing agents, generating different nanoparticle aggregation behaviors and visible color changes. l-Tryptophan causes strong aggregation and a purple color, while d-tryptophan yields dispersed particles and a light pink color, enabling visual and spectrophotometric enantiomeric discrimination. At each fixed total tryptophan concentration, the absorbance at 570 nm increased with increasing d-Trp mole fraction, allowing the enantiomeric composition to be estimated. Separate linear relationships between absorbance and d-Trp mole fraction were obtained at total tryptophan concentrations ranging from 104 µM to 3.3 mM. TEM analysis showed predominantly discrete particles for d-tryptophan and extensively associated particles for l-tryptophan, with mean primary-particle sizes of approximately 43 and 47 nm, respectively. These optical and morphological observations establish distinct enantiomer-dependent endpoint colloidal states but do not, by themselves, identify their chiroptical origin. The integrated synthesis-detection approach provides a rapid and inexpensive proof-of-concept for estimating enantiomeric composition in compositionally defined d-Trp/l-Trp mixtures. Selectivity in the presence of other amino acids, reducing substances, chelating agents, or complex matrix components was not evaluated in the present study.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Analytical Chemistry, Faculty of Chemistry and Petroleum Sciences, Bu-Ali Sina University Hamedan Iran m.ahmadi@basu.ac.ir."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Rozhin Radmanesh"
    },
    {
      "affs": [
        0
      ],
      "name": "Mazaher Ahmadi",
      "orcid": "0000-0001-9969-170X"
    },
    {
      "affs": [
        0
      ],
      "name": "Tayyebeh Madrakian"
    },
    {
      "affs": [
        0
      ],
      "name": "Abbas Soloki"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8nqgmvyh0qn2r.bib",
  "cited_by": 0,
  "doi": "10.1039/d5ra09954d",
  "fulltext_url": "https://europepmc.org/articles/PMC13644728",
  "id": "8nqgmvyh0qn2r",
  "issns": [
    "2046-2069"
  ],
  "landing_url": "https://europepmc.org/article/MED/42846972",
  "language": "eng",
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2504|Gold and Silver Nanoparticles Synthesis and Applications"
    ]
  ],
  "openalex": "W7220866976",
  "pdf_url": "https://europepmc.org/articles/PMC13644728?pdf=render",
  "pmcid": "PMC13644728",
  "pmid": "42846972",
  "published": "2026-10-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8nqgmvyh0qn2r.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:02Z",
      "native_id": "MED:42846972",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42846972"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2504|Gold and Silver Nanoparticles Synthesis and Applications",
      "subfield": "materials-polymers"
    }
  ],
  "title": "In situ synthesis of gold nanoparticles using tryptophan enantiomers for determination of enantiomeric composition.",
  "title_text": "In situ synthesis of gold nanoparticles using tryptophan enantiomers for determination of enantiomeric composition.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:02Z",
  "url": "https://research.draconitic.com/paper/8nqgmvyh0qn2r",
  "venue": "RSC advances",
  "versions": []
}