• What it is. This fluoride standard contains 1 mg/L (1 ppm) fluoride ion in water and comes in a 500 mL bottle. It is a calibration and check standard for fluoride measurements by ion-selective electrode (ISE) and other methods used in drinking water and environmental testing.
  • Why 1 mg/L. A 1 mg/L standard falls within the range of many drinking water fluoride results, so it serves as a calibration point or check standard close to real sample values. Measuring near the sample concentration reduces error compared with calibrating only at much higher levels.
  • How fluoride standards are made. Fluoride standards are typically prepared from sodium fluoride (NaF, 41.99 g/mol). At 1 mg/L as fluoride, the solution contains about 2.21 mg of sodium fluoride per liter (calculated from the fluoride fraction of NaF).
  • Ion-selective electrode calibration. A fluoride ISE responds to fluoride activity, which depends on the solution's ionic strength and pH. Methods therefore add a total ionic strength adjustment buffer (TISAB) in equal volume to standards and samples to fix ionic strength, set the pH, and free fluoride bound to aluminum or iron.
  • Calibration practice. Calibrate with at least two standards that bracket the expected sample range, treat standards and samples identically with TISAB, and measure them at the same temperature. Rinse the electrode with deionized water between readings, and check calibration during sample runs with a mid-range standard such as 1 mg/L.
  • Quality control. Running a 1 mg/L check standard at the start, middle, and end of a batch confirms that the electrode slope and calibration hold. Results outside your acceptance limits signal the need to recalibrate or service the electrode before reporting data.
  • Where it is used. Drinking water utilities use fluoride standards to monitor fluoridation; environmental and wastewater labs use them for monitoring; dental and toothpaste product testing uses them for product testing; and teaching labs use them to demonstrate ISE measurements.
  • Handling and storage. At 1 mg/L, the solution contains only a trace amount of fluoride. Store it tightly closed, protected from light, at controlled room temperature, and use clean plastic labware, since fluoride can be lost to glass surfaces at low concentrations.

Technical Specifications

Product Fluoride ion standard solution
Analyte Fluoride ion (F-)
Concentration 1 mg/L (1 ppm) as F-
Source Compound (typical) Sodium fluoride, NaF
CAS Numbers (typical) 7681-49-4 (sodium fluoride); 7732-18-5 (water). Confirm on SDS
Molecular Weight (NaF) 41.99 g/mol
Sodium Fluoride Equivalent About 2.21 mg/L (calculated)
Fluoride per mL 0.001 mg
Matrix Water (confirm whether premixed with TISAB)
Primary Use Fluoride ISE calibration and verification
Physical State Liquid, aqueous solution
Storage Room temperature, tightly closed, protected from light
Recommended Pairing TISAB (equal volume); bracketing standards such as 0.5 and 2 mg/L
Odor Odorless
Measurement Method Fluoride ion-selective electrode
Package Size 500 mL

Applications / Common Uses

  • Fluoride ISE calibration: Provides a 1 mg/L calibration point.
  • Check standard: Verifies calibration during sample batches.
  • Drinking water testing: Supports fluoridation monitoring.
  • Environmental analysis: Calibrates fluoride measurements in water and wastewater.
  • Teaching labs: Demonstrates ion-selective electrode measurement.

Storage, Handling & Shipping

Store the standard tightly closed at room temperature, protected from light, and use it within the period stated on the label or certificate after opening. Pour portions into clean plastic containers for each use and never return used standard to stock.

  • Labware: Use clean plastic labware; avoid storing dilute fluoride standards in glass.
  • Contamination control: Never return used standard to stock or dip electrodes into the container.
  • Personal protection: Safety glasses and gloves as standard laboratory practice.
  • Spill response: Wipe up and rinse the area with water.

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