Method 7902

Particulate and gaseous flourides by Ion Specific Electrode

This method is for the determination of aerosol and gaseous fluorides. The sample is collected on cellulose ester membrane filters with sodium carbonate treated cellulose pads, followed by extraction. Particulate fluorides are fused in sodium hydroxide and then dissolved in 50mL water and TISAB (total ionic strength activity buffer). Gaseous fluorides are extracted with 50mL water and TISAB. The sample is then analyzed with an ion specific electrode. The working range is 0.12 to 8 mg/m³ for a 250-L air sample. The method applies to mining samples, and samples from the aluminum reduction, ceramic, glass etching, electroplating, semi-conductor, and fluorochemical industri es. If other aerosols are present, gaseous fluoride may be underestimated owing to sorption on collected particles, with concurrent overestimation of particulate/gaseous fluoride ratio. This revises method 7902 which was withdrawn on 5/15/89. The method was originally based on a method by Elfers and Decker, and NIOSH method S176 for HF. Method 7903 (Acids, Inorganic) is an alternative method for HF. Method 7906 (Fluorides by IC) employs the same sampling procedure, but uses ion chromatography for measurement.

(NIOSH Issue 2: 15 August 1994)


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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   Stable.
Preservatives:   Stable.
Required Preps:   Cellulose ester membrane filter, 0.8µm and sodium carbonate-treated cellulose pad.
Collection Method:   Filter and treated pad; 12L to 800L @ 1-2L/min.
Analytical Methodology:   Ion Specific Electrode.
Documentation:   7902

Analyte List*

Analyte Formula CAS Number Detection Limit
Gaseous Fluorides
Particulate Fluorides

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.