{'fraction_non_alphanumeric': 0.030335861321776816, 'fraction_numerical': 0.027085590465872156, 'mean_word_length': 5.03921568627451, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
SPECTROPHOTOMETRIC METHOD FOR ESTIMATION OF PARA PHENYLENEDIAMINE IN HAIR DYES

A new visible spectrophotometric method was developed for the determination of paraphenylenediamine (PPD) in pure and marketed forms using β‐naphthol as chromogenic reagent. This is based on reaction of PPD with β‐naphthol in acidic media to yield reddish‐pink coloured chromogen exhibiting absorption maximum at 552.4 nm. Beer’s law is obeyed in the concentration range of 200‐1000 ng/mL with coefficient of determination as 0.9976. The limit of detection (LOD) and limit of quantitation (LOQ) were found to be 64.2 ng/mL and 194.8 ng/mL respectively. The developed method has been validated as per the ICH Q2 (R1) guidelines. The results demonstrate that the method is linear, precise and accurate. The proposed method was successfully applied for determination of PPD in different brands of hair dyes with good recovery and reproducibility.