Page:NIOSH Manual of Analytical Methods - 7903.pdf/1

 This method is considered historical and its use is no longer recommended. Please see the ‘Applicability’ Section for additional information. Revised: 15 July 2015.

ACIDS, INORGANIC

(1) HF; (2) HCl; (3) H3PO4; (4) HBr; (5) HNO3; (6) H2SO4 METHOD: 7903, Issue 2

MW: Table 1

7903

CAS: Table 1

EVALUATION: FULL

OSHA : Table 1 NIOSH: Table 1 ACGIH: Table 1

Issue 1: 15 February 1984 Issue 2: 15 August 1994

PROPERTIES: Table 1

SYNONYMS: 	(1) hydrofluoric acid; hydrogen fluoride (2) hydrochloric acid; hydrogen chloride (3) phosphoric acid; ortho-phosphoric acid; meta-phosphoric acid (4) hydrobromic acid; hydrogen bromide

MEASUREMENT

SAMPLER:	 SOLID SORBENT TUBE (washed silica gel, 400 mg/200 mg with glass fiber filter plug)

TECHNIQUE:

ION CHROMATOGRAPHY

ANALYTE:

F, Cl, PO4 3-, Br, NO3, SO42-

IC

FLOW RATE:	 0.2 to 0.5 L/min

DESORPTION:

3L 100 L

10 mL 1.7 mM NaHCO3/1.8 mM Na2CO3

INJECTION LOOP VOLUME: 50 μL

HI ST OR

SHIPMENT:	 routine

SAMPLE STABILITY:	 stable at least 21 days @ 25 °C [1] BLANKS:

(5) nitric acid; aqua fortis (6) sulfuric acid; oil of vitriol

AL

SAMPLING

VOL-MIN: -MAX:

RTECS: Table 1

ELUENT:

1.7 mM NaHCO3/1.8 mM Na2CO3; 3 mL/min

COLUMNS:

HPIC-AS4A anion separator, HPIC-AG4A guard, anion micro membrane suppressor [2]

2 to 10 field blanks per set ACCURACY

RANGE STUDIED:

see EVALUATION OF METHOD

BIAS:

see EVALUATION OF METHOD

OVERALL PRECISION ( SˆrT ):

see EVALUATION OF METHOD

ACCURACY:

± 12 to ± 23%

CONDUCTIVITY SETTING: 10 μS full scale RANGE:

see EVALUATION OF METHOD

ESTIMATED LOD: see EVALUATION OF METHOD PRECISION (

S r ):

see EVALUATION OF METHOD

APPLICABILITY: This method should no longer be used and has been replaced by NIOSH methods 7906, 7907, & 7908. The replacement methods (7906, 7907, & 7908) allow for the collection of inhalable fractions of acid aerosols by means of a prefilter and can provide for lower limits of detection for acid gases and vapors due to higher sampling flow rates. The working range is ca. 0.01 to 5 mg/m3 for a 50-L air sample (see EVALUATION OF METHOD). This method measures the total concentration of six airborne anions. The corresponding acids may be collected on a single sampler and determined simultaneously. Formic acid has been determined by this method [3]. INTERFERENCES:	 Particulate salts of all the acids will give a positive interference. Chlorine or hypochlorite ion interfere with chloride determination and bromine interferes with bromide. Silica gel will collect ca. 30% of the free Cl2 and Br2 in an atmosphere [4]. Acetate, formate and propionate have elution times similar to F- and Cl-. If these anions are present, use a weak eluent (e.g., 5 mM Na2B4O7) for greater resolution. OTHER METHODS: This is P&CAM 339 in a revised format [5]. Alternate methods are NIOSH 7902 for fluoride [6] and P&CAM 268 for sulfate [7].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition