Page:NIOSH Manual of Analytical Methods - 8304.pdf/1

 BENZIDINE in urine (SCREENING TEST)

C12 H12 N2

MW: 184.24

METHOD: 8304, Issue 2

CAS: 92-87-5

8304

RTECS: DC9625000

EVALUATION: PARTIAL

Issue 1: 15 February 1984 Issue 2: 15 August 1993

BIOLOGICAL INDICATOR OF: exposures to benzidine-based azo dyes.

SYNONYMS: [1,1'-biphenyl]-4,4'-diamine

BIOLOGICAL SAMPLING

SPECIMEN:

MEASUREMENT TECHNIQUE:

VISIBLE ABSORPTION/THIN LAYER CHROMATOGRAPHY (TLC)

ANALYTE:

2,4,5-trinitrobenzene sulfonic acid derivative of benzidine

WAVELENGTH:

400 nm

TLC IDENTIFICATION:

UV and visible R f = 0.41

ESTIMATED LOD:

0.1 µg/100 mL urine (visible absorption); 0.3 µg/100 mL urine (TLC)

CALIBRATION:

aqueous solutions of benzidine

QUALITY CONTROL:

frozen pooled urine

RANGE:

0.1 to 20 µg/100 mL urine

RECOVERY:

70% @ 0.5 µg/100 mL urine

PRECISION (Sr):

0.12 @ 0.5 µg/100 mL urine

ACCURACY:

± 53%

2 urine samples, 150 mL each, before and after 6 h of exposure

PRESERVATIVE: none SHIPMENT:

with dry ice in insulated container

STABILITY:

stable for 2 months @ - 20 °C

CONTROLS:

collect urine from non-exposed workers

APPLICABILITY: This method is specific for aromatic amines and can be used to screen workers exposed to benzidine or benzidine-based azo dyes.

INTERFERENCES: In addition to false positives from other free aromatic amines, some drugs (e.g., antihistamines) contain free aromatic amines; however, these compounds do not produce R f values corresponding to benzidine by TLC.

OTHER METHODS: This method replaces P&CAM 315 [1] with minor revisions. Method 8306 is a specific method for benzidine in urine by electron capture gas chromatography.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/93