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

instrument / verified-clean

# Absorbance-to-Concentration (Beer-Lambert)

The current ledger marks this instrument verified clean within the source-bound verification corpus.

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

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/absorbance-to-concentration-beer-lambert/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

**Tranche**: tranche-5

**Evidence ID**: t5-157

**Ledger rows**: 1

No ledger note is attached.

## Review findings

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.

### Formula and scope findings

No additional record

### Unit assumptions

- 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.

## Boundary hardening

**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.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

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

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche5/tranche5-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`