Page:NIOSH Manual of Analytical Methods - 5011.pdf/1

 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