Page:NIOSH Manual of Analytical Methods - 0801.pdf/1



AEROBIC BACTERIA by GC-FAME	0801

METHOD: 0801, Issue 1

EVALUATION: N/A

Issue 1: 15 January 1998

PROPERTIES:	 viable and culturable, requires oxygen SYNONYMS:	 Gram positive (+) bacteria, gram negative (−) bacteria, Mycobacterium species (sp) SAMPLING SAMPLER:	 ANDERSEN IMPACTOR (15 × 100-mm culture plates containing TSBA media)

MEASUREMENT TECHNIQUE:

GAS CHROMATOGRAPHY, FID

ANALYTE:

fatty acid methyl esters (FAME) of aerobic bacteria or Mycobacterium sp

DESORPTION:

1 mL hexane/MTBE (1:1)

INJECTION VOLUME:

2 µL

FLOW RATE:	 28.3 L/min [1] VOL-MIN: -MAX:

50 L 300 L

SHIPMENT:	 keep cold, ship overnight. SAMPLE STABILITY:	 transfer bacteria to fresh culture media weekly

TEMPERATURE-INJECTION:	250 °C -DETECTOR:	300 °C -COLUMN:	170 °C to 270 °C (5 °C/min)

BLANKS:

CARRIER GAS:

helium, 2.4 mL/min

COLUMN:

capillary, fused silica, 25 m × 0.20-mm ID, 0.33-µm film, Ultra-2 [2]

CALIBRATION:

MIDI fatty acid methyl ester calibration mix (containing various C9–C20 fatty acids)

not applicable ACCURACY

RANGE STUDIED:

not applicable

BIAS:

not applicable

OVERALL PRECISION :	not applicable IDENTIFICATION:	 comparison with profile library ACCURACY:

not applicable

ACCEPTABLE GENUS IDENTIFICATION:	 similarity index (SI) > 0.30 ACCEPTABLE SPECIES IDENTIFICATION:	 SI > 0.50

APPLICABILITY: This method is applicable to all viable and culturable bacteria containing C9–C20 fatty acids. The method is applicable to bulk solid and liquid samples containing culturable bacteria, as well as air samples. INTERFERENCES: No specific interferences were identified. However, any fungi, yeasts, or other source of fatty acid materials will affect identification of bacteria. Additionally, any organic contaminants will interfere with the identification process. OTHER METHODS: Method 0800, Bioaerosol Sampling, is a general procedure for sampling bioaerosols in air.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition