Multivariate optimization, in conjugation with matrix solid-phase dispersion and digital image detection, allows residual dye determination from shrimp samples

Here, we report an optimization of the extraction of crystal violet and congo red dyes from shrimp samples, employing matrix solid phase dispersion and improved multivariate optimization. Three factors were evaluated: (i) adsorbent nature (neutral alumina, silica gel and C₁₈); (ii) eluent strength (dimethylformamide, methanol and acetonitrile); and (iii) sample-adsorbent ratio (1:1; 1:5; and 1:10, m/m). Successful extraction of dyes was achieved using dimethylformamide as eluent, neutral alumina as adsorbent and sample:adsorbent ratio of 1:5 (m/m). Adsorption and kinetic studies suggest strong interaction between dye and adsorbent. Furthermore, employing digital image colorimetric detection, the study observed limit of detection (LOD) ranging between 3.8 to 29.8 µg L ^{− 1} and limit of quantification (LOQ) ranging between 12.3 to 90.3 µg L ^{− 1} with R² > 0.9927 for both dyes, CV and CR, respectively. Notably, recovery was greater than 86 % with a relative standard deviation (RSD) inferior to 7 % (n = 3). These findings indicate the effectiveness of the improved multivariate optimization technique in conjunction with matrix solid-phase dispersion for successful extraction and quantification of dyes from shrimp samples, showing its potential for accurate and sensitive detection in similar analyses. The proposed method was compared with the gold method (UV/Vis spectroscopy) and the statistical treatment showed that the results of both methods are comparable.