# getIonBalance

> Charge balance of a sample. Concentrations (mg/L) are converted to meq/L with the vocabulary molar mass and charge (mg/L ÷ (M / |z|)).

> **getIonBalance**(`sample`): [`IonBalance`](/utils/api/type-aliases/IonBalance) \| `undefined`

Charge balance of a sample. Concentrations (mg/L) are converted to meq/L
with the vocabulary molar mass and charge (`mg/L ÷ (M / |z|)`).

Cations: Ca, Mg, Na, K, Li, Fe (as Fe²⁺), Mn, NH₄⁺ (`ammonia_as_n`).
Anions: HCO₃⁻ + CO₃²⁻ (falling back to `alkalinity_total_as_caco3`), Cl⁻,
SO₄²⁻, F⁻, PO₄³⁻, NO₃⁻ and NO₂⁻ (the `_as_no3`/`_as_no2` code preferred
over `_as_n`, never both). Rejected and censored (`<`, `>`,
`not_detected`) results are left out.

`error_pct = (Σcat − Σan) / (Σcat + Σan) × 100`. Returns `undefined`
without at least one measured cation and one measured anion.

## Parameters

### sample

`WaterSample`

## Returns

[`IonBalance`](/utils/api/type-aliases/IonBalance) \| `undefined`