Abstract

The current study was designed to explore greener avenues into the traditional leather testing for banned aromatic amines according to the standard method ISO/DIS 17234-1/(IUC 20-1), with final quantification performed through GC-MS. The standard test procedure was used for initial screening of leather samples dyed with a bis azo dye, Direct Red 28 and substantial quantity of benzidine was released after reduction with sodium hydrosulphite. The effect of microwave heating and ultrasound assisted heating on reductive cleavage of dyed leather was investigated by adopting the established procedures for the analysis of specific aromatic amines in leather samples with slight variations in reduction process only. Dyed leather samples were exposed to ultrasonication in addition to heating at standard temperature for different durations of time. Similarly, in microwave assisted reduction MAR experiments, samples were exposed to microwave energy in successive cooling and heating cycles (pulses) for heating durations of 2 and 3 minutes. Samples in all experimental trials were estimated with GC-MS. Results obtained from MAR and ultrasound assisted reduction (UAR) trials were compared with those from standard test method for leather revealing that the former were carried out in lesser time and were also energy efficient. The energy saving was 80.6% whereas time saving was 22.2% in case of UAR as compared to the standard method. Similarly, 93.6% of energy saving and 73.3% of time saving was achieved with MAR. The effect of ultrasonic energy could be utilised for reaction enhancement as an option where there are temperature restrictions such as in case of reactions in biological systems or with bio materials. Pulse microwave is another powerful technique, currently explored for analytical purpose. The work is a step towards green analytical chemistry which is the pathway to sustainability.