Microplate-based 3D-printed image box for urea determination in milk by digital image colorimetry

Author(s)

da Penha, Geovanna Morgado ; Pereira, Airton Vicente ; Tavares, Emily Amabile ; dos Santos Jr, Daniel Almeida ; Fatibello-Filho, Orlando

• Document type: Journal article
• Source: ANALYTICAL METHODS; v. 16, n. 33, p. 8-pg., 2024-08-05.

Abstract

In this study, we describe a rapid and high-throughput smartphone-based digital colorimetric method for determining urea in milk. A compact and cost-effective 3D-printed image box microplate-based system was designed to measure multiple samples simultaneously, using minimal sample and reagent volumes. The apparatus was applied for the quantification of urea in milk based on its reaction with p-dimethylaminobenzaldehyde (DMAB). The predictive performance of calibration was evaluated using RGB and different colour models (CMYK, HSV, and CIELAB), with the average blue (B) values of the RGB selected as the analytical signal for urea quantification. Under optimized conditions, a urea concentration linear range from 50 to 400 mg L-1 was observed, with a limit of detection (LOD) of 15 mg L-1. The values found with the smartphone-based DIC procedure are in good agreement with spectrophotometric (spectrophotometer and microplate treader) and reference method (mid-infrared spectroscopy) values. This proposed approach offers an accessible and efficient solution for digital image colorimetry, with potential applications for various target analytes in milk and other fields requiring high-throughput colorimetric analysis. Detecting milk adulteration with a smartphone and a fully 3D-printed device designed to analyse multiple samples simultaneously. (AU)

• FAPESP's process: 24/04116-8 - Use of deep eutectic solvents in sustainable spectrophotometric and electroanalytical procedures
• Grantee: Orlando Fatibello Filho
• Support Opportunities: Regular Research Grants