Source: https://guthlabs.ai/docs/instruments/ng-to-pmol-copy-number-converter/implementation/

instrument implementation / implementation-contract

# ng-to-pmol / Copy Number Converter implementation

A source-bound implementation contract for ng-to-pmol / Copy Number Converter; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t4-110

**Effect**: Computation or source lookup only

## Input and validation requirements

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.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "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."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/ng-to-pmol-copy-number-converter/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/ng-to-pmol-copy-number-converter/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/ng-to-pmol-copy-number-converter/qualification/>)

## 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`