99% O Toluidine General Purpose Reagent For Pest Killers

General Purpose Reagent O-Toluidine For Pest Killers

O-Toluidine is used as an intermediate in the synthesis of the large-volume metolachlor and acetochlor, herbicides, in the manufacture of more than 90 dyes and pigments (e.g. azo pigment dyes, acid-fast dyestuffs, triarylmethane dyes, indigo compounds and sulfur dyes), and as an intermediate for synthetic rubber and rubber-vulcanizing chemicals, pharmaceuticals, pesticides, and other chemicals. O-Toluidine is also used in the clinical laboratory as an ingredient in a reagent for glucose analysis, and for tissue staining.

Occupational exposure

Occupational exposure to o-toluidine can occur by inhalation or skin contact during its production, or during the production of pigments, dyes and rubber chemicals manufactured from this chemical. Medical personnel and laboratory may be exposed when using o-toluidine for staining tissues (IARC, 2010).

From the US National Occupational Exposure Survey (1981–83) it was estimated that 30000 (including approximately 15500 women) workers, were potentially exposed to o-toluidine (NIOSH, 1990). But no estimates of the number of exposed workers in the European Union have been reported.

At a chemical plant in the former Soviet Union where o-toluidine was produced via reduction of o-nitrotoluene, workers were exposed to concentrations of o-toluidine in the air that generally exceeded the maximum permissible concentration by 2–7-fold. In a total of 215 air samples, the highest exposure levels were observed during distillation and extraction processes (25–28.6 mg/m3). Dermal exposures also were documented (Khlebnikova et al., 1970). Measurements in the 1940s in a US dye-production plant indicated that the concentration of ortho-toluidine was < 0.5 ppm [2 mg/m3] in the workroom air and in the breathing zone of the workers, and < 0.3–1.7 mg/L in the urine of workers engaged in the production of thio-indigo (Ott & Langner, 1983). Exposure to ortho-toluidine was also reported to occur in plants involved in dye-production in Italy (Rubino et al., 1982), Germany (Stasik, 1988), and the USA (New Jersey) (Delzell et al., 1989), but no data on exposure levels were provided.

Medical and laboratory personnel also are potentially exposed to o-toluidine, although air concentrations are reportedly low (EPA, 1984; Kauppinen et al., 2003).

Concentrations of o-toluidine in indoor air in plants producing rubber antioxidants or vulcanising rubber articles ranged up to several hundred µg/m3 and o-toluidine concentrations in post-shift urine samples were around 100 µg/L (Ward et al., 1991; Teass et al., 1993; Ward et al., 1996; Korinth et al., 2006).

Non-occupational exposure

Significant non-occupational exposures to o-toluidine may result from the use of some hair dyes, tobacco smoke or the local anaesthetic prilocaine. In a study from Turkey (Akyüz & Ata, 2008), o-toluidine was found in 34 of the 54 hair dyes tested, at levels up to 1547 µg/g. Prilocaine, a widely used anaesthetic, is metabolized to o-toluidine. In 25 patients, who received local anaesthesia, the average amount of o-toluidine adducts to haemoglobin (Hb) increased 6–360-fold, from 0.54 ± 0.95 ng/g Hb before treatment to 22 ± 13.2 ng/g Hb at 24 hours after surgery (Gaber et al., 2007). o-Toluidine has been measured in mainstream cigarette smoke at 9–144 ng per cigarette (Stabbert et al., 2003), and concentrations in urine of smokers are higher than in non-smokers (Riffelmann et al., 1995; Riedel et al., 2006). o-Toluidine has also been detected in surface waters and industrial effluents (Shackelford & Keith, 1976; Neurath et al., 1977; EPA, 1984; NTP, 2004), in vegetables such as kale, celery and carrots, in the volatile aroma of black tea (Vitzthum et al., 1975; Neurath et al., 1977), and in breast milk (DeBruin et al., 1999), but levels are generally very low.