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

instrument mechanism / verified-clean

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

The inspectable method record for Absorbance-to-Concentration (Beer-Lambert), kept separate from implementation and qualification.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Model scope

The formula A = ε·l·c and rearrangement c = A/(ε·l) are standard for molar absorptivity with compatible units. Verdict is NEEDS_REVIEW because the input specification does not explicitly define the units or required positivity constraints, and optional extinction-coefficient presets require wavelength and experimental-condition metadata.

No additional formula finding is recorded.

## Units and conventions

- Absorbance A is dimensionless.

- The extinction coefficient ε is molar absorptivity in L·mol⁻¹·cm⁻¹ (equivalently M⁻¹·cm⁻¹).

- Path length l must be in centimeters when ε is expressed per centimeter.

- The output concentration c is in mol·L⁻¹ (M).

- The analyte, wavelength, solvent, pH, temperature, and other conditions must match the selected ε value.

## Inspectable vector

One of 4 source-bound review vectors:

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

## Failure boundary

**BREAK_CLAIMED** · SELF_FLAGGED

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.

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/>)[03**Implementation**](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/implementation/>)[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`

- `BOUNDARY_HAZARD_CATALOG.json`