Determination of hydrazine in tobacco smoke by HPLC
Hydrazine is known to be a human carcinogen with a dangerous level of exposure being 50 ppb (Occupational Safety & Health Administration (OSHA) 2008; EPA 2008). Hydrazine is part of a family of highly volatile liquids and is present in tobacco and cigarette smoke, consequently the risk of exposure through inhalation is of great concern.
The development of a simple method for the qualitative and quantitative determination of hydrazine in tobacco smoke is presented as follows.
This method uses HPLC with photo diode array (PDA) detector, wherein cigarette smoke is trapped into an impinger containing a mixture of methanol and 0.1 N sulphuric acid in the ratio (70:30). The smoke extract is derivatised using benzaldehyde solution wherein the hydrazine is converted to benzalazine and subsequent chromatographic separation on Lichrospher RP – 18e (250 mm × 5 micron × 4.0 mm) (Merck), under isocratic conditions using a mobile phase containing acetonitrile (70%) methanol (5%) and distilled water (25%).
The separations are monitored by PDA detector at 313 nm. Retention time for hydrazine derivative is found to be 8.5 ±0.5 min and retention time for benzaldehyde is found to be 3.0 ±0.5 min at a flow rate of 1.0 ml/min. Quantitation is based on the external standard technique. The method has been validated by standard validation protocols i.e. limit of detection, limit of quantification, recovery, repeatability and reproducibility. Minimum recovery of 70.8% was obtained with a linear regression coefficient of 0.9998 for the range of 20 to 4000 ppb hydrazine and limit of detection was 20 ppb.
The method presented here provides several advantages over the current ones in terms of factors such as speed, simplicity and ease of sample preparation. The method was found suitable for rapid determination of hydrazine in cigarette smoke.