Page:NIOSH Manual of Analytical Methods - 3507.pdf/1



ACETALDEHYDE by HPLC	3507 CH3CHO   MW: 44.05   CAS: 75-07-0   RTECS: AB1925000 METHOD: 3507, Issue 2

EVALUATION: FULL

OSHA:	 200 ppm NIOSH:	carcinogen; lowest feasible ACGIH:	 C 25 ppm; suspect carcinogen (1 ppm = 1.801 mg/m³ @ NTP)

Issue 1: 15 August 1987 Issue 2: 15 August 1994

PROPERTIES:	 liquid; d 0.78 g/mL @ 20 °C; BP 20.4 °C; MP −123 °C; VP 100 kPa (750 mm Hg; 99% v/v) @ 20 °C; explosive range 4 to 60% in air

SYNONYMS:	 ethanal; acetic aldehyde SAMPLING

MEASUREMENT

SAMPLER:	 LIQUID IN BUBBLER (midget bubbler containing 15 mL Girard T solution @ pH 4.5)

TECHNIQUE:

HPLC, UV

ANALYTE:

Girard T derivative

FLOW RATE:	 0.1 to 0.5 L/min

SAMPLE PREPARATION:

VOL-MIN: -MAX:

6 L @ 200 ppm 60 L

SHIPMENT:	 seal bubblers to prevent leakage before shipping; protect from light SAMPLE STABILITY:	 1 week @ 25 °C in dark [1] FIELD BLANKS:

2 to 10 field blanks per set ACCURACY

RANGE STUDIED: BIAS:

INJECTION VOLUME:

50 µL

COLUMN:

50 cm × 2-mm ID SS, Zipax SCX

DETECTOR:

UV @ 245 nm for acetaldehyde

MOBILE PHASE:	 Na2HPO4/NaH2PO4 buffer, 0.75 mL/min CALIBRATION:

standard solutions of acetaldehyde in Girard T reagent

170 to 670 mg/m³ [1] (60-L samples)

RANGE:

2 to 60 mg per sample [1]

1.2%

ESTIMATED LOD:	 0.1 mg per sample [1]

OVERALL PRECISION :	0.053 [1] ACCURACY:

dilute 5 mL sample to 100 mL with HPLC mobile phase

PRECISION :

0.024 @ 11 to 43 mg per sample [1]

±14.4%

APPLICABILITY: The working range is 18 to 372 ppm (33 to 670 mg/m³) for a 60-L air sample. The method is sensitive enough for short-term exposure sampling and can be used to measure lower concentrations by diluting samples to less than the recommended 100 mL. INTERFERENCES: Other volatile aldehydes and ketones (e.g., acetone, acrolein, benzaldehyde, formaldehyde, furfural, methyl ethyl ketone, and propionaldehyde) compete for the Girard T reagent which should be kept at a two-fold molar excess over aldehyde concentration. Chromatographic conditions may be adjusted to resolve acetaldehyde from other aldehydes [1]. OTHER METHODS: This revises S345 [2]. Method 2538 is an adaptation of OSHA Method 68, which uses solid sorbent collection and GC analysis. Other reported methods for acetaldehyde use collection in 2,4-dinitrophenylhydrazine solution [3,4].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition