Using a Smartphone-Based Colorimetric Device with Molecularly Imprinted Polymer for the Quantification of Tartrazine in Soda Drinks

Abstract

The present study reports the development and application of a rapid, low-cost in-situ method for the quantification of tartrazine in carbonated beverages using a smartphone-based colorimetric device with molecularly imprinted polymer (MIP). The MIP was synthesized using the free radical precipitation method with acrylamide (AC) as the functional monomer, N,N′-methylenebisacrylamide (NMBA) as the cross linker, and potassium persulfate (KPS) as radical initiator. The smartphone (RadesPhone)-operated rapid analysis device proposed in this study has dimensions of 10 × 10 × 15 cm and is illuminated internally by light emitting diode (LED) lights with intensity of 170 lux. The analytical methodology involved the use of a smartphone camera to capture images of MIP at various tartrazine concentrations, and the subsequent application of the Image-J software to calculate the red, green, blue (RGB) color values and hue, saturation, value (HSV) values from these images. A multivariate calibration analysis of tartrazine in the range of 0 to 30 mg/L was performed, and the optimum working range was determined to be 0 to 20 mg/L using five principal components and a limit of detection (LOD) of 1.2 mg/L was obtained. Repeatability analysis of tartrazine solutions with concentrations of 4, 8, and 15 mg/L (n = 10) showed a coefficient of variation (% RSD) of less than 6%. The proposed technique was applied to the analysis of five Peruvian soda drinks and the results were compared with the UHPLC reference method. The proposed technique showed a relative error between 6% and 16% and % RSD lower than 6.3%. The results of this study demonstrate that the smartphone-based device is a suitable analytical tool that offers an on-site, cost-effective, and rapid alternative for the quantification of tartrazine in soda drinks. This color analysis device can be used in other molecularly imprinted polymer systems and offers a wide range of possibilities for the detection and quantification of compounds in various industrial and environmental matrices that generate a color change in the MIP matrix.

Preparation of a Molecularly Imprinted Polymer on Polyethylene Terephthalate Platform Using Reversible Addition-Fragmentation Chain Transfer Polymerization for Tartrazine Analysis via Smartphone

“…A procedure adapted from a previously documented MIP synthesis [15] was employed. The polymerization process began by mixing 0.1 mmol of TZ with 0.2 mmol of AA in 40 mL of water and stirring for 2 h. Subsequently, nitrogen bubbled for 10 min, followed by the addition of 10 mmol of N,N ′ -methylenebisacrylamide, 1 mL of the RAFT reagent dissolved in ethanol (2 mg mL −1 ), and 1 mL of potassium persulfate in water (1 mg mL −1 ).…”

“…RadesPhone was used, a device previously reported by our research group [15], for image capture. Moreover, 1 cm 2 MIP-PET or NIP-PET plates were submerged in a tartrazine solution at pH 3.0 and agitated on an orbital shaker for 2 h. Subsequently, the plates were washed and vacuum-dried.…”

“…The color intensity measurement on the MIP-PET plates exposed to the tartrazine solutions is performed by extracting the RGB color values from the images at a size of 16 × 16 pixels using ImageJ 1.53k software. These colors were then converted into other color channels, such as HSV and CMYK, using Equations ( 3) and (4) [19], which have been reported for use in other studies [13,15].…”

“…The use of water at room temperature and at 70 • C, as reported by Arabzadeh et al [23], was not suitable for our work, as the MIP retained a yellow color and showed low adsorption capacity. Tartrazine extraction with 20% ammonia has been employed in previous research [15,24]. This method was selected as the most suitable, using a washing protocol consisting of 15 min of treatment with 20% ammonia solution under ultrasound and then an additional 24 h of agitation.…”

“…The second step involves studying the correlation between the chromatic value or its function and the analyte concentration through appropriate mathematical treatment. Within a specific concentration range, the chromaticity of the colored substance is related linearly or nonlinearly to its concentration, enabling the analysis of the sample after establishing a calibration curve with the original color values [14] using chemometric methods [15] or machine learning techniques [16]. Overall, these applications using smartphones can simplify traditional analysis methods, resulting in fast and user-friendly technologies [17].…”