Hydrazine. Determination in workplace air with high performance liquid chromatography – spectrophotometric technique

Abstract

Anhydrous hydrazine in room temperature is colorless fuming oily liquid with ammonia-like odor. It is used in various industries for electrolytic plating of metals on glass and plastics, as a chemical intermediate for the synthesis of pesticides, insecticides, medicines and days. It is used also as water treatment agent in energy industry (corrosion inhibitor), rocket propellant and as explosives material. Long term exposure to hydrazine may cause to skin irritation and allergic reactions. Diluted aqueous solutions of hydrazine may be irritating for skin, eye and respiratory tract. Epidemiologic studies shows that chronic exposure to hydrazine may cause cancer. In European Union hydrazine is classified as a carcinogenic substance (cat. 1B). Experts from International Agency for Research on Cancer (IARC) have classified hydrazine as a compound probably carcinogenic to humans (Group 2A). Due to decreasing of MAC value for hydrazine in Poland it was necessary to develop and validate a sensitive method for determining hydrazine concentrations in the workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of Standard No. PN-EN 482. The study was performed using a liquid chromatograph with spectrophotometric detection. All chromatographic analysis were performed with Discovery LC-18 150 × 2,1 mm analytical column, which was eluted with mixture of acetonitrile and water (6:4 v/v). The method is based on the collection of hydrazine on glass fiber filter impregnated with sulfuric acid, extraction with mixture of sodium dihydrogen phosphate and EDTA, derivatization of extracted compound with benzaldehyde and chromatographic determination of resulted solution with HPLC technique. The method is linear (r = 0.9989) within the investigated working range 0.15–3.5 μg/ml (0.00125–0.029 mg/m3 for a 240-L air sample). Calculated limit of detection (LOD) and limit of quantification (LOQ) were 0.0007 μg/ml and 0.0023 μg/ml, respectively. The average extraction efficiency of hydrazine from filters was 97% and samples stored in refrigerator are stable for 14 days. The analytical method described in this paper enables determination of hydrazine in workplace air. The method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard No. PN-EN 482. The method can be used for assessing occupational exposure to hydrazine and associated risk to workers’ health. The developed method of determining hydrazine has been recorded as an analytical procedure (see appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.