ETHYLENE THIOUREA
C3H6N2S
MW: 102.17
METHOD: 5011, Issue 2
CAS: 96-45-7 EVALUATION:
RTECS: NI9625000
PARTIAL
OSHA : suspect carcinogen NIOSH: lowest feasible; carcinogen ACGIH: no TLV
5011
Issue 1: 15 February 1984 Issue 2: 15 August 1994
PROPERTIES: solid; MP 203 to 204 °C
SYNONYMS: 2-imidazolidinethione, ETU; 4,5-dihydroimidazole-2(3H)-thione.
SAMPLING SAMPLER:
FILTER (5-µm PVC or mixed cellulose ester membrane)
MEASUREMENT TECHNIQUE:
VISIBLE ABSORPTION SPECTROPHOTOMETRY
FLOW RATE:
1 to 3 L/min
ANALYTE:
ETU-pentacyanoamineferrate coordination complex
VOL-MIN: -MAX:
200 L @ 0.05 mg/m 3 800 L
EXTRACTION:
distilled water, stand 45 min @ 60 °C
SHIPMENT:
routine COMPLEXATION:
pentacyanoamineferrate reagent
SAMPLE STABILITY:
unknown
WAVELENGTH:
590 nm
BLANKS:
2 to 10 field blanks per set
CALIBRATION:
solutions of ETU in water
BULK SAMPLE:
required; high-volume air or settled dust
RANGE:
10 to 150 µg per sample
ESTIMATED LOD:
0.75 µg per sample
PRECISION (Sr):
0.03
ACCURACY RANGE STUDIED:
0.03 to 1.5 mg/m 3 (100-L sample)
BIAS:
not significant [3]
ˆ ): not determined OVERALL PRECISION (S rT ACCURACY:
not determined
APPLICABILITY: The working range is 0.05 to 0.75 mg/m 3 for a 200-L air sample. Ethylene thiourea is used in the manufacture of fungicides, rubber vulcanization and in dyes, pharmaceuticals, synthetic resins and electroplating baths [1]. The met hod was also applied to tetramethyl thiourea [1].
INTERFERENCES: Compounds containing a thione (C=S) group will complex with the pentacyanoamineferrate reagent and may interfere with the ETU absorbance band at 590 nm.
OTHER METHODS: This method was originally designated P&CAM 281 [2], which it replaces.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
