Function purityGradeToPercentage

purityGradeToPercentage(grade: string): undefined | number

Converts a purity grade to a representative percentage.

NOTE: chemical grades are specifications, not fixed purities — the real assay minimum for a given grade varies by chemical, and the lower grades (lab/pure/practical/technical) have no formally defined standard at all. These values are therefore representative figures chosen to rank grades in the correct order, intended only for sorting/comparison — not as assays. Ties within a tier are intentional (e.g. USP/BP/JP/NF are ~equivalent).

Ordering follows the standard hierarchy (highest→lowest): HPLC > ACS > Reagent ≈ AR ≈ Guaranteed > USP ≈ BP ≈ JP ≈ NF > Pharma ≈ FCC > Cosmetic ≈ Extraction ≈ Lab > Pure ≈ Practical > Technical ≈ Industrial > Low > Impure

Note "Impure" maps to 0, which is a value, not a miss — only "Ungraded" and unrecognised labels return undefined.

Parameters

grade: string
The grade label (as returned by parseGrade, e.g. "ACS Grade")

Returns undefined | number

A representative purity %, or undefined if unrecognised

Example

purityGradeToPercentage("ACS Grade")       // 99.8
purityGradeToPercentage("USP Grade")       // 99.5
purityGradeToPercentage("Technical Grade") // 90
purityGradeToPercentage("Impure")          // 0
purityGradeToPercentage("Ungraded")        // undefined

Source

export const purityGradeToPercentage = (grade: string): number | undefined => {
  switch (grade) {
    // ── Instrumental / analytical: highest purity ──
    case 'HPLC Grade': // low interfering impurities; solvents typically ≥99.9%
      return 99.9;
    case 'ACS Grade': // meets/exceeds ACS reagent specs — top of the standard hierarchy
      return 99.8;
    case 'AR Grade': // Analytical Reagent — high purity, ≈ ACS
    case 'Guaranteed Grade': // "Guaranteed Reagent" (GR) — high purity, ≈ ACS
    case 'Reagent Grade': // almost as stringent as ACS
      return 99.7;

    // ── Pharmacopeia (food/drug-acceptable) ──
    case 'USP Grade': // meets US Pharmacopeia; equivalent to ACS for many drugs
    case 'BP Grade': // British Pharmacopoeia
    case 'JP Grade': // Japanese Pharmacopoeia
    case 'NF Grade': // National Formulary
      return 99.5;
    case 'Pharma Grade': // generic pharmaceutical
    case 'FCC Grade': // Food Chemicals Codex — food-safe
      return 99.0;

    // ── Intermediate: good quality, no strict assay floor ──
    case 'Cosmetic Grade':
    case 'Extraction Grade': // rough guess — not part of a formal purity hierarchy
    case 'Lab Grade': // high quality, exact impurities unknown; education use
      return 98.0;

    // ── No official standard ──
    case 'Pure Grade': // "pure"/"purified" — good quality, meets no official standard
    case 'Practical Grade': // same tier as purified
      return 95.0;

    // ── Commercial / industrial: lowest ──
    case 'Technical Grade': // industrial/processing use; not for food/drug
    case 'Industrial Grade':
      return 90.0;

    case 'Low Grade':
      return 50.0;

    case 'Impure':
      return 0.0;
    // "Ungraded" and anything unrecognised fall through to undefined.
    default:
      return undefined;
  }
};