Simultaneous spectrophotometric determination of Tartrazine, Sunset Yellow and Ponceau 4R in commercial products by partial least squares and principal component regression multivariate calibration methods

Three multivariate calibration methods, partial least squares (PLS-1 and PLS-2) and principal component regression (PCR), were proposed and successfully applied to the simultaneous determination of three dyes, Tartrazine (E-102), Sunset Yellow (E-110) and Ponceau 4R (E-124) in mixtures by ultraviolet-visible absorption spectrophotometry. The designed and optimized training set of calibration was applied to the determination of the three dyes in several synthetic mixtures, containing 1.6–20.0 mg/L of Tartrazine, 3.2–40.0 mg/L of Sunset Yellow and 3.2– 36.0 mg/L of Ponceau 4R. 94.5–105.3% recovery values were obtained. Three commercial foods that contained the three dyes were also satisfactorily analyzed without separation step. The results obtained by the application of the three chemometric approaches in the commercial products are discussed and compared with those obtained by an HPLC method and very similar values were found by all methods. Repeatability and reproducibility studies (with the Student’s and F tests) were achieved over two series of nine standards for each dye, showing no significant differences at the 95% confidence level.     

Resolution of ternary mixtures of Tartrazine, Sunset yellow and Ponceau 4R by derivative spectrophotometric ratio spectrum-zero crossing method in commercial foods

A very simple spectrophotometric method is described for resolving ternary mixtures of the food colorants Tartrazine, Sunset Yellow and Ponceau 4R by using the first derivative of the ratio spectra with measurements at zero-crossing wavelengths. Calibration graphs are linear up to 20 mg l(-1) of Tartrazine (E-102), 40 mg l(-1) of Sunset Yellow (E-110) and 32 mg l(-1) of Ponceau 4R (E-124). Standard deviations of 0.9, 0.8 and 2.4% were obtained for nine standards of 8 mg l(-1) of Tartrazine, 8 mg l(-1) of Sunset Yellow and 8 mg l(-1) of Ponceau 4R, respectively. This method was satisfactorily used for determining synthetic mixtures of these colorants in different ratios (from 1:1:1 to 1:5:5 or even higher) with recoveries in 94-105% range and it was successfully applied over three commercial products containing the three dyes and it did not require any separation step. The results were compared with those obtained by HPLC and very similar values were found by both methods.     

Rapid spectrophotometric method to resolve ternary mixtures of Tartrazine, Quinoline Yellow and Patent Blue V in commercial products

A very simple spectrophotometric method is described for resolving ternary mixtures of the food dyes Tartrazine (E-102), Quinoline Yellow (E-104) and Patent Blue V (E-131) by using the second derivative of the spectra with measurements at zero-crossing wavelengths. Calibration graphs are linear up to 20.0 mg/L of Tartrazine, up to 20.0 mg/L of Quinoline Yellow and up to 6.4 mg/L of Patent Blue V. Repeatability and reproducibility studies (with the Students’s and F tests) were achieved for two series of nine standards for each dye showing no significant differences at the 95% confidence level. Detection limits of 0.0526, 0.0164 and 0.0034 mg/L were obtained for Tartrazine, Quinoline Yellow and Patent Blue V, respectively. This method was used for determining synthetic mixtures of these colorants in different ratios and it was successfully applied to four commercial products without previous separation step. The results found in commercial products were compared with those obtained by an HPLC method and very similar values were found for both methods. Received: 28 December / Revised: 26 May 1999 / Accepted: 31 May 1999     

Rapid spectrophotometric method to resolve ternary mixtures of Tartrazine, Quinoline Yellow and Patent Blue V in commercial products

A very simple spectrophotometric method is described for resolving ternary mixtures of the food dyes Tartrazine (E-102), Quinoline Yellow (E-104) and Patent Blue V (E-131) by using the second derivative of the spectra with measurements at zero-crossing wavelengths. Calibration graphs are linear up to 20.0 mg/L of Tartrazine, up to 20.0 mg/L of Quinoline Yellow and up to 6.4 mg/L of Patent Blue V. Repeatability and reproducibility studies (with the Students’s and F tests) were achieved for two series of nine standards for each dye showing no significant differences at the 95% confidence level. Detection limits of 0.0526, 0.0164 and 0.0034 mg/L were obtained for Tartrazine, Quinoline Yellow and Patent Blue V, respectively. This method was used for determining synthetic mixtures of these colorants in different ratios and it was successfully applied to four commercial products without previous separation step. The results found in commercial products were compared with those obtained by an HPLC method and very similar values were found for both methods.     

Simultaneous determination of tartrazine and sunset yellow by derivative spectrophotometry and ratio spectra derivative

Two methods for determining Tartrazine and Sunset Yellow in mixtures by first derivative spectrophotometry and by first derivative of the ratio spectra are described. The procedures do not require any separation step. By the first method, the measurements are obtained in the zero-crossing wavelengths and the calibration graphs are linear up to 20 microg/ml of Tartrazine and up to 40 microg/ml of Sunset Yellow. The determinations of Tartrazine and Sunset Yellow are also done by the first derivative of the ratio spectra. The methods are applied for determining both compounds in four commercial food products.     

Rapid Spectrophotometric Method for Determining Erythrosine,Amaranth and Tartrazine in Ternary Mixtures

Abstract

A very simple spectrophotometric method using measurements at zero-crossing wavelength is described for resolving ternary mixtures of the food colorants Erythrosine (E-127), Amaranth (E-123) and Tartrazine (E-102). Calibration graphs are linear up to 14 mg/L of Erythrosine and 28 mg/L for Tartrazine and Amaranth. RSD of 0.80, 0.85 and 1.84% were obtained for nine standards of 8 mg/L of Erythrosine, 8 mg/L of Tartrazine and 8 mg/L of Amaranth, respectively. Detection limits of 0.052, 0.934 and 0.123 mg/L were obtained for Erythrosine, Tartrazine and Amaranth, respectively. This method was satisfactorily used for determining synthetic mixtures of these colorants in different ratios and it was successfully applied to a commercial product containing the three dyes; no separation step is required. The results were compared with those obtained by liquid chromatography and very similar values were found by both methods.     

Simultaneous spectrophotometric determination of tartrazine, patent blue V, and indigo carmine in commercial products by partial least squares and principal component regression methods

Two multivariate calibration methods, partial least squares (PLS-1) and principal component regression (PCR) were proposed and successfully applied to the simultaneous determination of three dyes, tartrazine (T) (E-102), patent blue V (P) (E-131), and indigo carmine (I) (E-132) in mixtures by ultraviolet-visible absorption spectrophotometry. Calibration models were evaluated by internal validation (prediction of dyes concentration in its own designed training set of calibration), by cross-validation (obtaining statistical parameters that show the efficiency for a calibration fit model), and by external validation over 19 synthetic mixtures of the three dyes in different ratios containing 2.4-17.6 mg l(-1) of T, 1.6-5.6 mg l(-1) of P, and 3.2-17.5 mg/l(-1) of I, with recoveries between 93.5 and 103.1% and over three commercial products, in which the proposed calibration models were satisfactorily applied without separation step. Repeatability and reproducibility studies (with the Students's and F tests) were achieved over two series of nine standards for each dye, showing no significant differences at 95% confidence level.     

Simultaneous determination of food dyes by first derivative spectrophotometry with sorption onto polyurethane foam.

A simple spectrophotometric method is described for resolving binary mixtures of some food dyes: Amaranth, Brilliant Blue, Sunset Yellow and Tartrazine, using the first-derivative spectra with measurements at zero-crossing wavelengths. Analytical curves are linear up to 20 mg L(-1). Standard deviations of 1.30, 2.22, 1.93 and 0.81% were obtained for synthetic binary mixtures of 2 mg L(-1) of Amaranth, Brilliant Blue, Sunset Yellow and Tartrazine, respectively. Before the spectrophotometric measurements, the dyes were sorbed onto polyurethane foam and recovered in sodium dodecyl benzene sulfonate solution. Therefore, matrix complexity was eliminated and simple spectra were obtained. The method was very satisfactorily used for determining the colorants in synthetic mixtures, with recoveries in the 96 - 101% range. Detection limit values were dependent on the colorant combination investigated. Commercial products containing binary combinations of these dyes in different ratios (from 1:1 to 1:8) were analyzed. The results were compared with those obtained by HPLC; very similar values were found by the two methods.     

Multicomponent Chemometric Determination of Colorant Mixtures by Voltammetry

Abstract

A quantitative chemometric approach, iterative target transformation factor analysis (ITTFA), was applied to the simultaneous determination of mixtures of four food colorants (Amaranth, Sunset Yellow. Tartrazine and Ponceau 4R) by adsorptive voltammetry. The conventional and first-derivative voltammograms of the quaternary mixtures were used to perform the optimization of the calibration procedure by the ITTFA models. The proposed method was applied satisfactorily to the determination of a set of synthetic quaternary mixtures of colorant in phosphate/citric acid buffers (pH 5.7) and acceptable results were obtained. No significant advantages were found with the application of derivative technique in this voltammetric work.     

Qualitative and Quantitative Treatment of Thin-Layer Chromatograms of Incompletely Separated Synthetic Food Colors

A procedure for the qualitative and quantitative determination of dyes after thin-layer chromatographic separation is developed using an example of five synthetic food colors: Brilliant Blue, Tartrazine, Sunset Yellow, Ponceau 4R, and Azorubine. The chromatogram is scanned and saved in Windows 95/98 raster image format and processed by the Adobe Photoshop 5.0 program package. The procedure is applicable even when the dyes are incompletely separated on the chromatogram.     

Sorption of food dyes on polyurethane foam and aluminum oxide

The sorption of food dyes Sunset Yellow (E-110), Tartrazine (E 102), Ponceau 4R (E-124), Fast Green FCF (E-143) on polyether-based polyurethane foam, and α-Al₂O₃ from water solutions has been studied. It has been found that the maximum sorption is observed in the range of 0.2 M HCl-pH 2 on polyurethane foam and at pH 2–4 on aluminum oxide. Under the optimal conditions the recoveries on polyurethane foam and α-Al₂O₃ are 20–30% and 70–80%, respectively. It has been shown by diffuse reflectance spectroscopy that, for all dyes except for Fast Green FCF, only one form of the dye that dominates under these conditions in the aqueous solution is extracted on the sorbents in the range of 0.5 M HCl, pH 8.0. Possible models of the interaction between the dyes and the sorbent surface are proposed.     

A Reverse Phase HPLC Method to Determine Six Food Dyes Using Buffered Mobile Phase.

Abstract

A reverse phase high performance liquid chromatographic (HPLC) method to determine six food dyes (Sunset Yellow (E-110), Carminic acid (E-120) Carmoisine (E-122), Amaranth (E-123), Ponceau 4R (E-124) and Erythrosine (E-127) is developed in this paper. The separation was made on a Nova-Pack C18 column using methanol -NaH₂PO₄/Na₂HPO₄ pH=7 buffer solution 0.1M as mobile phase with an elution gradient system. The detection was made with a variable UV-Vis. detector fixed at 520 nm.

The effect of mobile phase composition such as the percentage of methanol or acetonitrile, pH value and ionic strength on retention times of the dyes was investigated. In the chromatographic conditions selected, the dyes were eluted in four minutes. Two calibration graphs for each dye were established by measuring the peak area and the peak height in the chromatograms. Determination limits ranging from 0.8 to 9.2 ng were obtained when the peak area was measured.

Several commercial products containing some of these dyes were analyzed.     

Determination of sulphonated azo dyes in food by ion-pair liquid chromatography with photodiode array and electrospray mass spectrometry detection

An ion-pair liquid chromatography method with on-line photodiode-array and electrospray mass spectrometry detection was developed to determine 10 commonly used sulphonated azo dyes (Tartrazine, Amaranth, New Coccine, Sunset Yellow FCF, Allura Red AC, Ponceau R, Ponceau 3R, Orange I, Orange II and Metanil Yellow) in food. A reversed phase C(18) column with gradient elution was utilized to separate these compounds. Triethylamine was added in the mobile phase as an ion-pair reagent for chromatographic separation. Photodiode-array detection was employed for quantitative determination and electrospray mass spectrometry was used for identification. Good linearity (0.05-10 ppm, r(2)=0.999) and detection limit (<0.01 ppm) were determined with 5 mul injection. In addition, precision and accuracy associated with this newly developed method will be presented. A liquid extraction method was also developed to extract these dyes from different foodstuffs. The application of this method was demonstrated by analyzing sulphonated azo dyes in soft drinks, fruit jam, and salted vegetables.     

Determination of dyes in foodstuffs by capillary zone electrophoresis

A rapid method based on capillary zone electrophoresis coupled with photodiode-array detection has been developed to determine the dyes Tartrazine E-102, Sunset Yellow FCF E110, Amaranth E-123, New Coccine E-124, Patent Blue V calcium salt E-131 and Allura Red AC E-129 in foodstuffs. Separation was done by using a Bare CElect-FS75 CE column, using a 10 mM phosphate buffer at pH 11.0. Hydrodynamic injections at 0.5 p.s.i. for 4 s (21 nl of sample) and 20 kV separation voltage were used. The quantitation limits for the six dyes ranged from 3 to 6 microg/ml. A linear relationship between 3 to 95 microg/ml, with correlation coefficient better than 0.995 was obtained. This method has been applied to the determination of the studied dyes in beverages, jellies and syrups.     

比值导数波谱法分析混合色素

本文叙述了比值导数波谱法的原理，该法以混合物的波谱除以干扰组分的标准波谱面得到比值波谱，以比值波谱对波长求导得到比值导数波谱，由此得到的波谱可完全消除干扰组分的吸光度贡献。采用此法能方便地对二组分混合体系进行分析，如选择合适的零交点，则可对二组分混合体系进行分析。利用此法对胭脂红、日落黄及柠檬黄三种色素的二组分及三组分混合体系进行了分析，均获较好的结果。     

Surface-enhanced oxidation and detection of Sunset Yellow and Tartrazine using multi-walled carbon nanotubes film-modified electrode

The insoluble multi-walled carbon nanotubes (MWNT) was successfully dispersed into water in the presence of hydrophobic surfactant. After that, MWNT film-coated glassy carbon electrode (GCE) was achieved via dip-coating and evaporating water. Owing to huge surface area, high sorption capacity and subtle electronic properties, MWNT film exhibits highly efficient accumulation efficiency as well as considerable surface enhancement effects to Sunset Yellow and Tartrazine. As a result, the oxidation peak currents of Sunset Yellow and Tartrazine remarkably increase at the MWNT film-modified GCE. Based on this, a novel electrochemical method was developed for the simultaneous determination of Sunset Yellow and Tartrazine. The limits of detection are 10.0 ng mL⁻¹ (2.2 × 10⁻⁸ mol L⁻¹) and 0.1 μg mL⁻¹ (1.88 × 10⁻⁷ mol L⁻¹) for Sunset Yellow and Tartrazine. Finally, the proposed method was successfully used to detect Sunset Yellow and Tartrazine in soft drinks.     

Simultaneous determination of drugs in concentration ratios above 40:1 by application of multivariate calibration to absorbance and derivative spectrophotometric signals

The performance of two multivariate calibration methods, multiple linear regression (MULTI3) and partial least-square regression (PLS-2), for the resolution of the ternary mixtures of acetylsalicylic acid-caffeine-codeine and acetaminophen-caffeine-codeine is compared. The methodologies were checked by applying them to the analysis of two sets of laboratory-prepared mixtures over the concentration ranges 13.0–19.0, 1.00–3.00 and 0.20–1.00 μg · ml^–1 for acetylsalicylic acid-caffeine-codeine and 12.0–22.0, 0.40–2.00 and 0.20–1.00 μg · ml^–1 for acetamimophen-caffeine-codeine, respectively. While the results provided by MULTI3 were unacceptable in the majority of the cases, those obtained by PLS-2 were quite good with considerably diminished errors, as a result of calibration and/or checking with MULTI3, taking no account of potential interactions between analytes. It was shown that it is possible by using PLS-2 to resolve complex mixtures of analytes in a highly disparate proportion, even when they have overlapping signals. The proposed method was successfully demonstrated for pharmaceutical tablets. Received: 7 February 1996 / Revised: 22 April 1996 / Accepted: 28 April 1996     

Simultaneous kinetic spectrophotometric analysis of five synthetic food colorants with the aid of chemometrics

This paper describes a simple and sensitive kinetic spectrophotometric method for the simultaneous determination of Amaranth, Ponceau 4R, Sunset Yellow, Tartrazine and Brilliant Blue in mixtures with the aid of chemometrics. The method involved two coupled reactions, viz. the reduction of iron(III) by the analytes to iron(II) in sodium acetate/hydrochloric acid solution (pH 1.71) and the chromogenic reaction between iron(II) and hexacyanoferrate(III) ions to yield a Prussian blue peak at 760 nm. The spectral data were recorded over the 500-1000 nm wavelength range every 2 s for 600 s. The kinetic data were collected at 760 nm and 600 s, and linear calibration models were satisfactorily constructed for each of the dyes with detection limits in the range of 0.04-0.50 mg L⁻¹. Multivariate calibration models for kinetic data were established and verified for methods such as the Iterative target transform factor analysis (ITTFA), principal component regression (PCR), partial least squares (PLS), and principal component-radial basis function-artificial neural network (PC-RBF-ANN) with and without wavelet packet transform (WPT) pre-treatment. The PC-RBF-ANN with WPT calibration performed somewhat better than others on the basis of the %RPE_T (∼9) and %Recovery parameters (∼108), although the effect of the WPT pre-treatment was marginal (∼0.5% RPE_T). The proposed method was applied for the simultaneous determination of the five colorants in foodstuff samples, and the results were comparable with those from a reference HPLC method.     

高脂肪食品中合成着色剂的检测

建立了高脂肪食品中合成着色剂的高效液相色谱检测方法。在碱性溶液中用正己烷萃取食品中的脂肪,分层后移除脂肪层,从剩余溶液中提取的柠檬黄、苋菜红、靛蓝、胭脂红、日落黄、诱惑红、亮蓝七种水溶性合成着色剂经高效液相色谱分离后,用二极管阵列检测器(DAD)检测,与标准溶液的保留时间、吸收光谱的特征及峰面积比较进行定性、定量;在优化的萃取pH值与色谱分析条件下,平均回收率在92.8%~102.1%之间,检出限为0.1 mg/kg。该法前处理简单,回收率高,操作简便,测定结果令人满意。     

Simultaneous Determination of Sunset Yellow and Ponceau 4R in Gelatin Powder by Derivative Spectrophotometry and Partial Least-Squares Multivariate Spectrophotometric Calibration

ABSTRACT

Two methods for the simultaneous determination of Sunset Yellow and Ponceau 4R in gelatin powders by first derivative spectrophotometry and by partial least-squares multivariate spectrophotometric calibration are described. These procedures do not require any separation step. These methods were applied to determine both colorants in commercial gelatin powders and the results obtained were compared. A good statistical agreement was obtained between the results.