Source: https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/implementation/

instrument implementation / implementation-contract

# Absorbance-to-Concentration (Beer-Lambert) implementation

A source-bound implementation contract for Absorbance-to-Concentration (Beer-Lambert); 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**: t5-157

**Effect**: Computation or source lookup only

## Input and validation requirements

A zero extinction coefficient or zero path length produces an undefined division and must be rejected. The specification also provides no numeric validity threshold or alternate formula branch, and path-length units can cause a 100-fold concentration error if interpreted inconsistently with the extinction-coefficient units.

## 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": {
    "absorbance": 0.5,
    "molar_extinction_coefficient": 15000,
    "extinction_coefficient_units": "M^-1 cm^-1",
    "path_length": 1,
    "path_length_units": "cm"
  },
  "expected_outputs": {
    "concentration": 0.0000333333333333,
    "concentration_units": "M"
  },
  "working": "c = A/(ε·l) = 0.500/(15,000 × 1) = 0.500/15,000 = 0.0000333333333333 M = 3.33333333333 × 10^-5 M."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/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-tranche5/tranche5-results.json`