Adsorption of Tartrazine onto Activated Carbon Based Cola Nuts Shells: Equilibrium, Kinetics, and Thermodynamics Studies

The uptake of tartrazine from its aqueous solution by powdered activated carbon prepared from cola nut shells chemically activated with potassium hydroxide (ACK) and phosphoric acid (ACP) has been investigated using kinetics models. Batch isotherm data were analysed with the pseudo-first order, pseudo-second order model as well as the intraparticle diffusion model. For structural elucidation, the materials were characterized using FTIR, XRD and SEM. These analyses revealed that the activated carbons (ACK and ACP) were predominantly mesoporous with several oxygen-containing functional groups dispersed on their surface. The reaction was systematically investigated under various experimental conditions such as contact time, adsorbent dose and pH. For the two adsorbents, the quantity adsorbed of 19.256 mg/g and 18.196 mg/g respectively for ACP and ACK at respective contact times of 5 and 10 min were obtained. The adsorption data were tested with the Langmuir, Freundlich models. Langmuir model was found to best describe the adsorption of tartrate ions with maximum monolayer adsorption capacities of 24.57 and 21.59 mg/g for ACP and ACK, respectively. Results analysis indicated clearly that the pseudo-second order kinetic rate model best fitted the experimental data and therefore was the adsorption controlling mechanism for both adsorbents. Thermodynamic studies revealed that the adsorption process was spontaneous and exothermic for ACP with increased randomness at the solid solution interface, then exothermic but non-spontaneous for ACK. The results show that these activated carbons could be an alternative for more costly adsorbents for the purpose of tartrate ions elimination.

Simultaneous Determination by HPLC-UV Vis of Tartrazine and Sunset Yellow in Soft Drinks Sold in Benin

The use of dyes such as tartrazine (E102) and sunset yellow (E102) in food, beverages and health products for technological and commercial purposes is common. The adverse effects caused by these dyes, such as allergies and hyperactivity disorder have been reported, especially in children. In the present study, a chromatographic method was developed and validated for simultaneous determination of tartrazine and sunset yellow. The chromatographic separation was performed on a Lichrocart® C18 column (125 × 4.6 mm;5 μm) with a security Guard-C18 column (4 × 2.0 mm, 5 μm;Phenomenex, Torrance, CA, USA) maintained at 30°C. The mobile phase consisted of a mixture of acetonitrile/ammonium acetate buffer pH 6.8 in gradient mode with a flow rate of 1 mL/min. The injection volume was 10 μL. The detection wavelength was set at 455 nm. The parameters of specificity, linearity, precision, repeatability, accuracy and sensitivity were examined for validation. The developed method is linear in the range of 1 μg/mL to 100 μg/mL with a R2> 0.998. The intra-day and inter-day precisions (RSD) were less than 0.6% and 3.1% respectively. The detection limit was 0.03 μg/mL and the quantification limit was 0.1 μg/mL. The retention time of tartrazine was 2.86 min, while sunset yellow was detected at 5.67 min. A simple, rapid, accurate and robust HPLC/UV-Visible method was developed and validated for simultaneous identification and quantification of tartrazine and sunset yellow. This developed method was successfully applied for the simultaneous determination of tartrazine and sunset yellow in soft drinks sold in Benin.

Tartrazine Exposure Assessment by Using Food Frequency Method in North Jakarta, Indonesia

Stipulating maximum level of food additives in food should be conducted to anticipate excessive usage, guarantee food safety, and as reference in food inspection. However, to support adequate stipulating, information about food aditives exposure assessment must available. In fact, this information is stills very few in Indonesia. Tartrazine is one of food additives that most frequently used in food product. The objective of this research was to conduct the exposure assessment of tartrazine from food products which have enlisted in National Agency for Drug and Food Control (NADFC) of Indonesia by using food frequency method with respondent from North Jakarta. The steps of research were survey preparation, food consumption survey from 150 respondents representing groups of children, adolescents, and adults, data processing, and data analysis. The result showed that mean value of food consumption containing tartrazine by all respondents was 306.38 g/person/day. The highest mean of consumption in total population groups was by children due to higher food consumption frequency and portion. The five highest food containing tartrazine which were consumed by all respondents were instant noodles, powder concentrate for beverages, non-carbonated beverages, carbonated beverages, and biscuits. All exposure assessment in this research did not exceed the Acceptable Daily Intake (ADI) for tartrazine. The mean value of exposure by all respondents was 231.24 μg/kg BW (3.08% ADI). The highest mean value of exposure in total population groups was by children due to their higher food consumption and lower body weight. The major contributing foods to tartrazine exposure were instant noodles, non-carbonated beverages, powder concentrate for beverages, biscuits, and snacks. Instant noodles had the highest mean value of consumption and tartrazine exposure for all respondents in North Jakarta. Respondent which had the highest mean value of consumption and tartrazine exposure was by children. Snacks were relative low consumed but high tartrazine exposure.

Oxidation and Complexation-Based Spectrophotometric Methods for Sensitive Determination of Tartrazine E102 in Some Commercial Food Samples

Two new sensitive spectrophotometric methods are reported for determination of tartrazine (Tz) (E102) in some commercial food samples. The first method involves two coupled reactions, the reduction of Cu(II) to Cu(I) by the analyte in acetate buffer medium (pH = 5.9) at 30°C and the complexation reaction between Cu(I) and Tz oxidized form to yield Cu-Tz complex (method I). The other method is based on oxidation of Tz by alkaline KMnO4. These reactions are monitored spectrophotometrically at maximum absorbances 332 and 610 nm for methods (I and II) respectively. Variables affecting these reactions are carefully studied and the conditions are optimized. The stability constants are calculated at 293, 303, 313 and 323 K. The thermodynamic parameters, Gibb’s free energy change (ΔG), entropy change (ΔS), and enthalpy change (ΔH) associated with the complexation reaction are calculated and discussed. Under optimized conditions the proposed methods (I, II) obey Beer’s law 10.69 - 85.50, 5.34 - 34.12 μg·ml-1 of Tz respectively. The molar absorptivity, sandel sensitivity, detection and quantification limits are calculated. Matrix effects are also investigated. The methods are successfully applied to the quantification of Tz in different commercially food samples. The results obtained are in good agreement with those obtained by the reported methods at the 95% confidence level.

Degradation of tartrazine by peroxymonosulfate through magnetic Fe_(2)O_(3)/Mn_(2)O_(3) composites activation

In this study,Fe_(2)O_(3)/Mn_(2)O_(3) composite was synthesized by a facile two-step technique,and several methods were carried out to characterize it.Then,the decomposition experiments of tartrazine(TTZ),a kind of refractory o rganic pollutant,were conducted under various enviro nmental condition to detect the catalyst performance,such as reaction system,the dosage of catalyst,peroxymonosulfate(PMS)concentration,initial pH,different natural water substances.The results exhibited that Fe_(2)O_(3)/Mn_(2)O_(3) composite with the mole rate 2:3 had the best PMS activation performance and the removal efficiency was 97.3%within 30 min.Besides,the optimum degradation conditions of TTZ we re also discussed,that is catalyst dosage(0.6 g/L),PMS concentration(0.8 g/L)and the initial pH 11.In addition,proved by the natural water substances adding experiments,HPO_(4)^(2)-,HCO_(3)^-,NO_(3)^-and NOM(nature organic matter)could slow down the experiments progressing,but Cl^-could boost it.Then inhibitor experiments indicated both the HO^·and SO_(4)^·-played a vital role in the experiments.Reusability and ions leaching experiments as well as the used catalyst physical characte rization images exhibited the excellent stability and cyclicity of the Fe_(2)O_(3)/Mn_(2)O_(3) composite.Finally,based on the XPS(X-ray photoelectro n spectro scopy)and the experiments results,the possible mechanism of TTZ degradation was proposed.This system might provide a novel thought for the decomposition of refractory organic pollutant and had potential in promotion of actual sewage treatment technology.

Preparation of chitosan/N-doped graphene natively grown on hierarchical porous carbon nanocomposite as a sensor platform for determination of tartrazine

In this work,the chitosan and N-doped graphene natively grown on hierarchical porous carbon（N-PC-G/CS） nanocomposite was obtained by ultrasonic method,as a novel sensor platform for determination of tartrazine（TT）.The nanocomposite as prepared had well dispersivity in water and excellent conductivity.The N-PC-G/CS nanocomposite was characterized by scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,nitrogen adsorption-desorption,fourier transform infrared（FTIR） and electrochemical impedance spectroscopy（EIS）.The application of N-PC-G/CS for determination of tartrazine（TT） was investigated by chronocoulometry（CC）,cyclic voltammetry（CV） and differential pulse voltammetry（DPV）.Under optimized conditions,the sensor displayed a sensitive response to TT within a wide concentration range of 0.05-15.0 μmol/L,the detection limits is 0.036 μmol/L（S/N = 3）.Furthermore,this nanocomposite could be efficiently applied for determination of TT in soft drink samples.

Thermostable Broad Band Polarizing PVA-Film: Theoretical and Experimental Investigations

In the present work, for the first time on the basis ofpoly （vinyl alcohol） （PVA）, 2- （4-dimethylaminostyryl）-l-ethylquinolinium iodide （quinaldine red （QR）） and trisodium （4E）-5-oxo- 1-（4-sulfonatophenyl）-4-[（4-sulfonatophenyl）hydrazono]-3 pyrazolecarboxylate （tartrazine （T））, thermostable polarizing film in a wide range of spectra （λmax=394-511 nm） with polarization efficiency （PE） = 98% in absorption maximum and stretching degree （Rs） = 3.5 was developed. The basic spectral-polarization parameters （polarization efficiency and transmittance） of oriented colored PVA-films were measured and discussed. During the work it was found that oriented PVA-films are the phenomenon of anisotropy of thermal conductivity （λ｜/λ⊥）. It is a very important parameter for the development of thermostable PVA-polarizing films. For the first time quantum-chemical calculations using density functional theory （DFT） approach for structural analysis and electronic spectrum of the QR were carried out via the B3LYP/dgdzvp and TDB3LYP/dgdzvp methods. Interpretation of absorption strips in visible region of spectrum was also reported. The excitation energies, electronic transitions and oscillator strengths for the studied structures have also been calculated （B3LYP/dgdzvp）. The NBO analysis and Mulliken atomic charges of the QR were carried out.