Analysis of free aniline in chrome-free leather accelerated aging

Under acidic conditions, aniline can react with nitrite diazotization, then diazotization can reaction products under the condition of alkaline naphthol coupled with armor and color. The product of this reaction has a maximum absorption at 495 nm. By using a series of optimized experiments, we obtained the optimum instrument operation parameters and reaction conditions to analyze aniline in leather extract solutions. Under optimal conditions, aniline concentration was within the range of 0.002-2.0 mg/L, and peak height (H, mV) and concentration (c, mg/L) had a linear relationship. The linear correlation coefficient was R² = 0.9997, the detection limit was 1.62 μg/L, and the RSD was 0.71%. Aniline in leather extract after accelerated aging was calculated using our calculation method, and the range of standard addition recovery was recorded to be between 97.8% and 103.8%. Compared with the national standard anti-interference method, our result recorded more accurate results and the relative mean absolute error (RAAE) was smaller. Our flow injection analysis combined with ultraviolet visible spectrophotometry (FIA-UV) method can eliminate interference due to trace elements in the extraction solution, as well as effectively improving accuracy and reliability for the determination of aniline in chrome-free leather extraction solution.