Development of a method for monitoring personal exposure to benzyl violet 4B and direct blue 15 in workplace air

OBJECTIVES The purpose of this research was to develop a method for monitoring personal exposure to benzyl violet 4B (BV) and direct blue 15 (DB) in workplace air for risk assessment. METHODS We evaluated the utility of the proposed method by examining the following: recovery; method limit of quantification; reproducibility; and storage stability of the samples. RESULTS An air sampling cassette containing a glass fiber filter was chosen as the sampler. BV and DB were extracted from the sampler filters with a solution of water and methanol (7:3, v/v) and then analyzed by a high-performance liquid chromatograph equipped with a photo-diode array detector. The overall recoveries from spiked samplers were 94-102% and 94-99% for BV and DB, respectively. The recovery after seven days of storage at 4°C exceeded 95%. The method limits of quantification were 0.250 and 1.25 μg/sample for BV and DB, respectively. The relative standard deviations, which represent the overall reproducibility defined as precision, were 0.6-4.1% and 0.8-2.9% for BV and DB, respectively. CONCLUSIONS The proposed method enables 4 h personal exposure monitoring of BV and DB at concentrations of 1-2,000 μg/m3 for BV and 5-2,000 μg/m3 for DB, with a 240 l sampling. Thus, the proposed method is useful for estimating worker exposure to BV and DB.