ng-to-pmol / Copy Number Converter mechanism

Model scope

The specification needs an explicit MW unit and a corrected pmol formula before release. Under the stated 650 g/mol/bp dsDNA assumption, use pmol=(mass_ng×1000)/MW_g_per_mol and copies=(mass_ng×10^-9/MW_g_per_mol)×6.02214076×10^23. Preserve the educational-estimate and not-medical-advice labeling.

• The pmol formula is incorrect if MW is in the standard g/mol units implied by the 650 g/mol/bp constant. The correct formula is pmol=(mass_ng×10^3)/MW_g_per_mol, equivalently (mass_ng×10^-9/MW_g_per_mol)×10^12.
• The copy-number formula is correct only when mass_g and MW_g_per_mol are used, but the declared input is mass(ng); the implementation must explicitly convert mass_g=mass_ng×10^-9.
• MW units are not specified. The pmol formula would differ by a factor of 1000 depending on whether MW is treated as g/mol or mg/mol, so the formula cannot be verified unconditionally.
• Length-based MW calculation is underspecified for RNA and single-stranded DNA. The supplied 650 g/mol/bp constant is identified as dsDNA-only and should not be applied to every molecule type.

Units and conventions

• For these test vectors, MW is assumed to be in g/mol.
• Mass input is assumed to be in ng and is converted to grams using mass_g=mass_ng×10^-9.
• pmol conversion uses 1 mol=10^12 pmol.
• Copy number uses Avogadro's constant N_A=6.02214076×10^23 mol^-1.
• For dsDNA length-based estimates, MW=650 g/mol/bp×length_bp, as specified; this is an average estimate, not sequence-specific molecular weight.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "mass_ng": 1,
    "length_bp": 1000,
    "MW_g_per_mol": 650000,
    "molecule_type": "dsDNA"
  },
  "expected_outputs": {
    "pmol": 0.00153846153846,
    "copies": 926483193.846154
  },
  "working": "MW=650×1000=650000 g/mol. pmol=(1 ng×1000)/650000=1000/650000=0.00153846153846 pmol. mass_g=1×10^-9=0.000000001 g. copies=(0.000000001/650000)×6.02214076×10^23=1.53846153846×10^-15×6.02214076×10^23=9.26483193846×10^8=926483193.846154 copies."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The supplied pmol formula is dimensionally inconsistent with mass in ng and molecular weight in g/mol: for 650 ng of a 1000-bp dsDNA molecule it returns 1000 pmol, while the copy-number formula gives 6.022×10^11 copies, corresponding to 1 pmol. The instrument also needs rejection handling for zero length, unsupported molecule types, and negative mass.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json
• BOUNDARY_HAZARD_CATALOG.json