Mercury_Speciation_Methyl_vs_Inorganic

URS & FS — User Requirements and Functional Specification

This document describes the controlled interface, user requirements and functional behaviour of Mercury_Speciation_Methyl_vs_Inorganic. The utility is intended for automated verification of laboratory, pharmacopoeial, analytical or manufacturing QC parameters using input.csv and producing a structured output.json result.

Domain limits and critical parameters

• • Total Mercury: ≤100 ppb (example)
• • Methylmercury: ≤50 ppb (example)
• • Inorganic Mercury: ≤50 ppb (example)
• • Mass Balance: Difference between sum of species and total Hg ≤15%
• Exceeding total mercury limits or form imbalance indicates contamination or analytical error.
• • Methylmercury (MeHg) is a highly toxic organic form that easily crosses the blood-brain barrier.
• • Inorganic Mercury (InorgHg) is less lipophilic but also nephrotoxic.
• • In fish oil and seafood, up to 90-95% of total mercury may be methylmercury.
• • Lumex RA-915M instruments allow determination of total mercury with high sensitivity. Speciation often requires chromatographic separation (LC-ICP-MS) or special kinetic/extraction methods.
• • Control of form balance validates the accuracy of the speciation method.
• • Sum of individual forms (MeHg + InorgHg) must equal Total Mercury (within error margin).
• • Methylmercury is a priority pollutant in food monitoring (Sanitary Rules).
• • For pharmaceutical fish oil, it is important to control both forms, as purification processes may affect them differently.
• • Calculation of percentage ratio of mercury forms.
• • Mass balance check of analytical data.
• • Support for data from hybrid systems or external chromatographs.

URS — User Requirements Specification

input.csv contract

BatchNumber,TotalHg_ppb,InorganicHg_ppb,MethylHg_ppb
FISH-OIL-SPEC-001,80.0,10.0,70.0
FISH-OIL-SPEC-002,95.0,15.0,80.0
FISH-OIL-FAIL-003,120.0,20.0,100.0

FS — Functional Specification

Example output.json

{
  "utilityId": "mercury-speciation-methyl-vs-inorganic",
  "utilityName": "Mercury_Speciation_Methyl_vs_Inorganic",
  "overallStatus": "PASS|WARNING|FAIL",
  "sourceFile": "input.csv",
  "checks": [
    {
      "parameter": "BatchNumber",
      "value": "FISH-OIL-SPEC-001",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "TotalHg_ppb",
      "value": "80.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "InorganicHg_ppb",
      "value": "10.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    },
    {
      "parameter": "MethylHg_ppb",
      "value": "70.0",
      "status": "PASS|WARNING|FAIL",
      "message": "Rule-based check result"
    }
  ],
  "criticalFindings": [],
  "warnings": [],
  "generatedFor": "QA/QC review and LIMS integration"
}

Traceability matrix

OQ/PQ test scenarios

QA/QC and change control

• Do not rename columns without updating the validator, documentation and test set.
• Retain input.csv, output.json, executable version, documentation and checksum.
• Before production use, perform IQ/OQ/PQ or equivalent CSV/CSA verification.
• Critical limits must be verified against the approved specification, local SOPs and registration dossier.