ICAMS 2016 – 6 th International Conference on Advanced Materials and Systems VALIDATION OF METHOD FOR 4-CHLOROANILINE AND 4,4'-BI-O- TOLUIDINE FROM DYED LEATHER CIPRIAN CHELARU, GABRIELA MACOVESCU, MARIAN CRUDU, DANA GURĂU INCDTP - Division Leather and Footwear Research Institute (ICPI),93 Ion Minulescu, Bucharest, Romania, cchelaru_cciprian@yahoo.com Toxicity assessment of leather products designed to obtain leather goods must be in accordance with legislation and environmental standards which require the use of chemicals from semi- finished leather processing. Azo dyes will be checked for two banned aromatic amines (4- chloroaniline and 4,4'-bi-o-toluidine) which can be found as a result of splitting azo dyes used to dye the leather. The method will be validated by gas chromatography (GC-MS) and the following parameters will be tested: accuracy (trueness and reliability), precision, sensitivity, detection limit, limit of quantification, working range, linearity. Keywords: Validation method, azo dyes, leather, 4-chloroaniline, 4,4'-bi-o-toluidine INTRODUCTION The most toxic products, mutagens, carcinogens (Eurachem Guide, 1998) were the first to have alarmed European Union and imposed publication of several directives that prohibit or limit the use of these chemicals (Directive 99/51/EC on pentachlorophenol, Directive 2002/61/EC banning azo dyes, Directive 2009/563/EC on eco-labelling footwear, Directive 2010/75/EU on industrial emissions in tanneries, REACH). Azo dyes account for about 90% of all dyes (Eurachem Guide, 1998) used for finishing leather and textiles. Azo dyes decompose under reductive conditions to form aromatic amines, derivatives of benzidine. 22 aromatic amines are banned in the EU Regulation 552/2009, and 2 more were added in 2015. EU Regulation provides test method for each type of substrate and defines the detection limit of 30 mg/kg for each amine that may be found in the leather and therefore this is the limit. Other aromatic amines from leather were investigated (www.cdc.gov; Huber, 2010; Chelaru et al., 2016). The objective of this study is to identify the presence of 4-chloroaniline, 4,4'-bi-o-toluidine used in dyed leather designated for clothing manufacture. MATERIALS AND METHOD Materials Methanol; T-butyl methyl ether; Sodium dithionite, minimum purity 87%; Aqueous solution of sodium dithionite, 200 mg/ml, prepared daily; N-hexane; Amines; Methanolic sodium hydroxide 20% (w/v), 20 g of NaOH dissolved in 100 ml of methanol; Distilled water - grade 3 according to SR EN ISO 3696: 2002 - Water used for analytical laboratories. Specifications and methods of analysis. Method Testing method for leather is established by EN ISO 17234-1:2015: Chemical tests for the determination of certain azo colorants in dyed leathers - Part 1 - Determination of certain aromatic amines derived from azo colorants.