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.     

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 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.     

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。     

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.     

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.     

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. Received: 27 October 1997 / Revised: 9 January 1998 / Accepted: 24 January 1998     

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.     

改良聚酰胺吸附-高效毛细管电泳内标法测定饮料中的亮蓝和苋菜红

以日落黄为内标物,建立了碳酸饮料中亮蓝和苋菜红的高效毛细管电泳内标测定方法。毛细管有效长度40 cm,内径75 μm,分离电压20 kV,进样量14 kPa×3 s,室温下分离,缓冲溶液为10 mmol/L磷酸氢二钠(pH 8.56),检测波长390 nm。亮蓝与苋菜红的相对校正因子分别为0.8329(相对标准偏差(RSD)为3.3%)和1.2253(RSD为2.6%);定量限(S/N=10)分别为1.629 mg/L和4.160 mg/L;回收率分别为97.87%～102.1%(RSD为1.8%)和94.07%～103.8%(RSD为4.1%);方法的精密度分别为3.2%和2.0%。对样品预处理的优化使该法更适用于碳酸类饮料中亮蓝和苋菜红的高效毛细管电泳分析。以样品空白为基液进行内标法定量测定,基本上消除了背景带来的系统误差。将该方法应用于实际样品的测定,结果准确。     

Color Characteristics of Aqueous Solutions of Synthetic Food Dyes

The color characteristics of aqueous solutions of synthetic food dyes Azo Rubine, tartrazine, Indigo Carmine, Ponceau 4R, Sunset Yellow, and Brilliant Blue were studied. A formula is proposed for determining the hue of dye solutions.     

Development of a green chromatographic method for determination of colorants in food samples

A green chromatographic analytical method for determination of Tartrazine, Brilliant Blue and Sunset Yellow in food samples is proposed. The method is based on the modification of a C18 column with a 0.25% (v/v) Triton X-100 aqueous solution at pH 7 and in the usage of the same surfactant solution as mobile phase without the presence of any organic solvent modifier. After the separation process on the chromatographic column, the colorants are detected at 430, 630 and 480 nm, respectively. The chromatographic procedure yielded precise results and is able to run one sample in only 8 min, consuming 15.0 mg of Triton X-100 and 38.8 mg of phosphate. When the flow rate of the mobile phase is 1 ml min⁻¹ the retention times are 2.1, 3.6 and 7.0 min for Tartrazine, Brilliant Blue and Sunset Yellow, respectively; and all peak resolutions are ca. 2. The analytical curves present the following linear equations: area = 7.44 10⁵ + 2.71 10⁵ [Tartrazine] (R = 0.998, n = 7); area = 1.09 10⁵ + 3.75 10⁵ [Brilliant] (R = 0.9995, n = 7) and area = −7.34 10⁴ + 2.33 10⁵ [Sunset] (R = 0.998), n = 7) and, the limits of detection for Tartrazine, Brilliant Blue and Sunset Yellow were estimated as 0.125, 0.080 and 0.143 mg l⁻¹. When the proposed method is applied to food samples analysis, precise results are obtained (R.S.D. < 5%, n = 3) and in agreement with those obtained by using the classical spectrophotometric method. The traditional usage of organic solvent as mobile phase in HPLC is not used here, which permits to classify the present method as green.     

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.     

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.     

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.     

导数伏安法同时测定5种混合人工合成色素

建立了同时测定胭脂红、柠檬黄、日落黄、赤藓红、苋菜红5种食用人工合成色素的1.5次线性扫描伏安法,并讨论了人工合成色素在悬汞电极上的反应机理.本方法简单快速,灵敏度高,重现性好,可以不经分离同时测定食品中的多种着色剂.     

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。     

比值导数波谱法用于极谱及伏安法多组分分析

叙述了比值导数波谱法在电化学波谱解析中应用的原理。首先以混合物的极谱波（或伏安波）除以干扰组分的标准波谱得到比值波谱，再以比值波谱对电位求导得到比值导数波谱，藉此可消除干扰组分的影响。采用该法可对二组分体系进行分析，如选择合适的零交点便可对三组分体系进行分析。利用本法对苋菜红－日落黄的伏安波及铜－镉－镍的极谱波进行了解析及定量分析，获较好的结果。     

XAD-2 HPTLC Method of Identification and Determination of Some Synthetic Food Colourings

Abstract

An HPTLC method for identification and determination of 12 synthetic dyes (Amaranth, Allura red, Brilliant black BN, Brilliant blue E, Carmoisine, Erythrosine, Indigotine, Patent blue V, Ponceau 4R, Quinoline yellow, Sunset yellow, Tartazine) has been developed. Amberlite XAD-2 was used as a stationary phase for column chromatography. Elution was performed with various acidified alcohols (i-propanol, n-propanol, n-butanol) and recoveries between 81.5 - 100.2% were obtained. The low limit of detection is in the range of 4 – 10 ng. The method was tested on commercial products as: carbonated soda, candies, chewing gum, identical natural flavours, etc.     

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.