Absorbance-to-Concentration (Beer-Lambert)

Inspectable records

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