Fabrication of β-cyclodextrin-coated poly (diallyldimethylammonium chloride)-functionalized graphene composite film modified glassy carbon-rotating disk electrode and its application for simultaneous electrochemical determination colorants of sunset yellow and tartrazine

We proposed a green and facile approach for the synthesis of β-cyclodextrin-coated poly(diallyldimethylammonium chloride)-functionalized graphene composite film (β-CD-PDDA-Gr) by using l-ascorbic acid (l-AA) as the reducing agent at room temperature. The β-CD-PDDA-Gr composite film modified glassy carbon-rotating disk electrode (GC-RDE) was then developed for the sensitive simultaneous determination of two synthetic food colorants: sunset yellow (SY) and tartrazine (TT). By cyclic voltammetry (CV), the peak currents of SY and TT increased obviously on the developed electrochemical sensor. The kinetic parameters, such as diffusion coefficient D and standard heterogeneous rate constant k_b, were estimated by linear sweep voltammetry (LSV). Under the optimal conditions, the differential pulse voltammetry (DPV) signals of SY and TT on the β-CD-PDDA-Gr modified GC-RDE were significantly enhanced. The enhanced anodic peak currents represented the excellent analytical performance of simultaneous detection of SY and TT in the range of 5.0 × 10⁻⁸ to 2.0 × 10⁻⁵ mol L⁻¹, with a low limit of detection (LOD) of 1.25 × 10⁻⁸ mol L⁻¹ for SY and 1.43 × 10⁻⁸ mol L⁻¹ for TT (S N⁻¹ = 3). This proposed method displayed outstanding selectivity, good stability and acceptable repeatability and reproducibility, and also has been used to simultaneously determine SY and TT in some commercial soft drinks with satisfactory results. The obtained results were compared to HPLC of analysis for those two colorants and no significant differences were found. By the treatment of the experimental data, the electrochemical reaction mechanisms of SY and TT both involved a one-electron-one-proton-transfer process.     

Simultaneous determination of tartrazine and sunset yellow in cosmetic products by first-derivative spectrophotometry

A spectrophotometric method for the simultaneous determination of Tartrazine (TT) and Sunset Yellow (SY) in cosmetic products has been developed. An extraction process was carried out using methylene chloride and the colouring matters were measured in the aqueous phase formed, the other components of the sample remaining in the organic phase. The applicable concentration ranges were 0.5–10 ug/ml TT and 0.5–12 g/ml SY. The detection limits were 26 and 11 ng/ml and the relative standard deviations were 1.0 and 0.9% for TT and SY, respectively. The method was applied to the determination of both compounds in cosmetics.     

Quick monitoring of coloring agents in highly consumed candies using multivariate calibration

Multivariate calibration are gaining popularity in assaying food matrices. Partial least squares is a powerful multivariate calibration method that used to build a quantitative relationship between measured variables and a property of interest (i.e., concentration) of the system under study. Partial least squares PLS calibration along with UV/vis spectral data was efficient to account for indirect food matrix and direct interference effects resulted from overlapping food dyes. PLS was able to quantify tartrazine TAT, allura red AR, sunset yellow SY and brilliant black BB that added to wide selection sugar-based candies. The results indicated that 70% of samples containing single dye while 8% containing TAT-SY mix and certain samples containing TAT + SY + AR + BB. Lollypops were found to contain high levels of AR (77–120 mg/kg) and TAT (56–166 mg/kg). The maximum adulteration was 50% observed in lollypops. PLS calibration was workable to predict colorants with prediction errors of 7%. Using PLS, dyes were detected down to 0.1 mg/L with acceptable accuracy and precision. PLS showed comparable performance with liquid chromatography for dyes quantification and can substitute laborious chromatography for quick detection of coloring agents in candies.     

Method Development and Validation for the Determination of Five Synthetic Food Colorants in Alcoholic Beverages by Reversed‐Phase High Performance Liquid Chromatography Coupled with Diode‐Array Detector

Abstract

An accurate method based on the use of reversed‐phase high performance liquid chromatography coupled with diode‐array detection was devised for the determination of five synthetic food colorants added to alcoholic beverages with natural colors. A C18 stationary phase was used and the mobile phase contained methanol and 40 mM ammonium acetate buffer solution. The synthetic food colorants were detected at their corresponding individual characteristic maxima of absorbance wavelength. Successful separation was achieved within 11 min for all the analytes using an optimized gradient elution, column temperature, buffer concentration and flow rate. Accurate sample quantification was feasible using matrix‐matched calibration curves. The method was successfully validated by determination of linearity ranges, the limits of quantification and detection, precision and recovery for all colorants tested. The proposed and validated method was used to analyze some alcoholic beverage samples, consisting of eight red wines, six coolers, four aromatized spirits, five bitters, three cocktails and four liquors from different Chinese manufacturers. The results showed the bitters and red wines did not have synthetic colorants, but colorants were found in all the samples of other kinds of alcoholic beverages. No analyzed sample exceeded the limit established by Chinese legislation.     

多元校正模型用于拼色食品中混合色素的同时测定

采用多元校正模型,不经分离,用吸光光度法同时测定拼色食品中混合合成色素,获得较满意的结果,同时对影响实际样品分析的因素进行了探讨。     

高效液相色谱-串联质谱法同时检测化妆品中6种禁用着色剂

建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时测定膏状和粉状化妆品中苏丹红IV、酸性紫49、苏丹蓝2、溶剂红49、碱性紫1和颜料橙5等6种禁用着色剂的检测方法。样品经乙醇-乙腈(3:2, v/v)超声振荡提取20 min、离心净化及氮吹浓缩后,在Luna C18色谱柱(150 mm×2.1 mm, 5 μm)上进行反相液相色谱分离,以甲醇和10 mmol/L乙酸铵溶液为流动相进行梯度洗脱,采用多反应监测(MRM)模式进行质谱测定。根据保留时间及质谱图上特征离子的相对丰度比进行定性,外标法定量。结果表明: 6种着色剂的定量限(信噪比为10计)为0.1～10 μg/kg,回收率为86.67%～98.22%,相对标准偏差(RSD)为4.01%～7.01%。该方法简便、快速、灵敏度高且重现性好,适合于化妆品中禁用着色剂的定性与定量。     

Automatic screening method for the rapid and simple discrimination between synthetic and natural colorants in foods

A simple screening method was developed to discriminate between synthetic and natural colorants present in foods in order to reduce the use of expensive instruments such as a liquid chromatograph with diode array detection. A rapid flow system was proposed in which samples containing natural and synthetic colorants in an acetic acid medium were passed through a wool/cotton column, where only synthetic colorants were retained and were then eluted with dilute ammonia. Yellow, red and green-blue-brown additives can be monitored at 400, 530 and 610 nm, respectively, with a conventional spectrophotometer. Complete discrimination (no false positives) between natural and synthetic colorants can be obtained for molar concentrations of natural colorants (in the absence of synthetic ones) up to 2000 (yellow), 2000 (red) and 10 000 (brown) times that of the detection limit (DL) of synthetic additives. The reliability of the method was established at five concentrations (between 0.5 and 3 DL) of the synthetic colorants tartrazine (yellow), erythrosin B (red) and brilliant black BN (brown). For a cut-off concentration of 2 DL, the percentage of false negatives ranges from 8 to 12%. Finally, the method was applied to screening several fruit drinks and candies for the determination of synthetic colorants with a sampling frequency of 10 h⁻¹.     

Abilities of Partial Least‐Squares (PLS‐2) Multivariate Calibration in the Analysis of Quaternary Mixture of Food Colors (E‐110, E‐122, E‐124, E‐131)

Abstract

Sunset Yellow (SY), Carmoisine (C), Ponceau 4R (P), and Patent Blue V (PB) are synthetic organic dyes which are under governmental regulations all over the world because of their toxicity and carcinogenicity.

In this study, a simple and fast analytical procedure was proposed for the simultaneous determination of food dyes (SY, C, P, and PB) in powder drinks by means the partial least‐square treatment of spectrophotometric absorbance between 450 –730 nm, taken at 10 nm intervals. The experimental calibration matrix was constructed with 27 samples. The concentration ranges considered were 2, 3, 4 µg · ml^?1 for SY, 7, 8, 9 µg · ml^?1 for C, 9, 10, 11 µg · ml^?1 for P, and 0.3, 0.4, 0.5 µg · ml^?1 for PB. The method was applied to the determination of dyes in different commercially available powder drinks. The results obtained by the application of the PLS‐2 method were statistically compared with those obtained by an HPLC method using the F and t tests. Very similar values were found by two methods. No time consuming pretreatment was needed and this method also provides rapid, accurate and economical analysis of these colors.     

冷焰ICP-MS法测定高纯稀土氧化物中铁和钙的研究

用冷焰技术对高纯稀土氧化物中Ｆｅ和Ｃａ的分析方法进行了研究。估算了测定范围和检出限,探讨了内标元素对基体影响的校正作用,测定了加标回收率,对半定量法（ＴＱ）和定量法（ＱＡ）的结果作了比较。表明冷焰条件下,痕量Ｆｅ的测定是可行的,但Ｃａ的测定结果仍不理想;ＱＡ法明显优于ＴＱ法。     

High-performance capillary electrophoretic analysis of synthetic food colorants

Summary A high-performance capillary electrophoresis method with diode-array detection has been developed for analysis of synthetic food colorants. The influence of buffer composition on the separation of the food colorants was examined, as were the effects of α-, β- and γ-c-yclodextrins on analyte migration behavior. Eight food colorants were completely separated within 10 min using pH 9.5 borax—NaOH buffer containing 5 mM β-cyclodextrin. Experimental results indicate that the relative standard deviations of analyte migration times were<0.88% under the optimized separation condition. Correlation coefficients of the linear calibration plots of the analytes exceeded 0.998. The method was suitable for determination of the quantities of synthetic food colorantsi in ice cream bars and fruit soda drinks.     

Determining eight colorants in milk beverages by capillary electrophoresis

Milk beverages are popular because of their high nutritional value, and milk products that are enhanced with various fruit flavors are especially in high demand in Asia. Colorants are usually added to fruit flavored milk in order to increase its attraction and appearance, therefore, the detection and measurement of colorants in this type of beverage are relatively important for health issue reasons. Carminic acid, a natural colorant, along with tartrazine, Fast green FCF, Brilliant blue FCF, Allura Red AC, Indigo carmine, Sunset yellow FCF, and New coccine, which are seven different synthetic food colorants, are commonly used as food additives, therefore, this study would focus on the development of an analytical method for the detection of these common colorants in milk beverages. A high efficiency capillary electrophoresis separation method was finished by a pH 10.0 running buffer containing 7.0 mM beta-cyclodextrin, and the eight colorants were separated with baseline resolution within 9 min. In order to reduce the matrix interference resulting from the constituents of milk, a suitable polyamide column solid-phase extraction (SPE) was also investigated for milk sample pretreatment. The combination of the simple SPE pretreatment and the fast separation method of capillary electrophoresis, was able to determine successfully without matrix interference the content of these colorant additives in commercial milk beverages. The recoveries of the eight food colorants in milk beverages were better than 85% and the detection limits were also lower than 0.5 microg/ml by the developed method.     

Comparison of different calibration approaches in the application of thermal desorption technique: A test on gaseous reduced sulfur compounds

In this study, the reliability of thermal desorbing technique was investigated using the gaseous standards of five reduced sulfur compounds (RSCs: hydrogen sulfide, methane thiol, dimethyl sulfide, carbon disulfide, and dimethyl disulfide). A series of calibration experiments for RSCs were performed using gas chromatography (GC) with pulsed flame photometric detector (PFPD) that is interfaced with a thermal desorber (TD) unit. These calibration data were evaluated by means of two contrasting concepts: fixed standard concentration method (FSC: variable volumetric injection of standard gases prepared at a given concentration) and fixed standard volume method (FSV: injection of multiple standards with varying concentrations at a given volume). When the results of both methods were compared, RSCs generally showed enhanced sensitivity with increasing concentration (FSC) and sample loading volume (FSV). This study highlights that TD-based calibration properties are practically undistinguishable between different sample transfer approaches (e.g., FSV and FSC). As a result, the calibration properties of RSCs derived by thermal desorption technique are greatly distinguished from those of direct injection into GC.     

高效液相色谱-串联质谱法测定保健食品中的23种精神药品

建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时测定保健食品中23种违禁精神药品的检测方法。样品经甲醇超声振荡提取20 min,于12000 r/min下离心后进行HPLC-MS/MS分析检测。采用Agilent Eclipse Plus C₁₈柱分离,流动相A为10 mmol/L甲酸铵溶液,流动相B为乙腈-甲醇(1:1, v/v)溶液,梯度洗脱;采用电喷雾离子源、正负离子模式切换、多反应监测(MRM)模式检测。23种精神药品在线性范围内线性关系良好,相关系数(R²)均大于0.990;检出限在0.02~1.0 μ g/L之间;3个添加水平的回收率为82.3%~114.8%,相对标准偏差(RSD)在1.3%~13.7%之间。样品筛查结果发现13种保健品中有1种样品非法添加了安宁,1种样品添加了奥沙西泮,2种样品添加了扎来普隆。该方法选择性强、灵敏度高、处理方法简单,可用于保健品中违禁镇静安神类化学药品的测定。     

Simultaneous spectrofluorometric determination of piroxicam and pyridoxine using generalized rank annihilation method.

The application of generalized rank annihilation method (GRAM) to the analysis of fluorescence excitation-emission matrices of mixtures of piroxicam and pyridoxine is described. The input of GRAM consists of two bilinear data matrices, i.e. one for unknown and one for the calibration sample. The excitation wavelength range was from 290 to 340 nm and the emission was recorded from 370 to 560 nm. Piroxicam and pyridoxine were determined in the concentration ranges 0.33 - 4.00 microg ml(-1) and 0.66 - 8.00 microg ml(-1), respectively. To check the accuracy of the proposed method, several binary synthetic mixtures and one real sample were analyzed successfully. No matrix effect was observed in mixture analysis, so a single external calibration sample was used for each analyte. The ability of GRAM to quantify the studied compounds and the comparability of GRAM results were evaluated by comparing them with those of PLS regression as a standard first-order calibration.     

离子色谱-质谱联用法检测食品中的糖醇

建立了离子色谱-质谱(IC-MS)联用方法检测食品中的糖醇。不同食品样品中的糖醇经提取后过SPE柱去除杂质,再经CarboPar MA1糖醇柱分离,在选择离子监测(SIM)模式下进行检测,外标法定量。各目标物在一定范围内线性关系良好,相关系数(R²)均大于0.99。赤藓糖醇、木糖醇、D-山梨糖醇、D-甘露糖醇、乳糖醇、麦芽糖醇的定量限(S/N=10)分别为0.98、1.99、2.24、5.92、13.56、13.21 mg/kg;检出限(S/N=3)分别为0.28、0.59、0.71、1.74、4.14、4.03 mg/kg。6种糖醇的加标回收率为82.5%~108.0%,相对标准偏差(RSD)为1.5%~7.6%。该方法的灵敏度、准确度和精密度均符合相关的技术要求,适用于食品中糖醇含量的检测。     

QuEChERS法结合高效液相色谱-串联质谱法测定保健食品中12种双酚类化合物

建立了采用高效液相色谱-串联质谱(HPLC-MS/MS)同时测定粉剂、片剂和胶囊剂等保健食品中12种双酚类化合物的检测方法。样品中双酚类化合物经1%(v/v)乙酸乙腈溶液提取,QuEChERS方法净化;12种化合物经Thermo Aquasil C₁₈色谱柱(150 mm×4.6 mm,3.0 μm)分离后,分别在串联质谱正、负离子多反应监测(MRM)模式下检测,基质匹配外标法定量。研究结果表明,在0.5~50.0 μg/kg内,12种双酚类化合物的线性相关系数均大于0.99,方法的检出限(S/N>3)为0.1~0.5 μg/kg,定量限(S/N>10)为0.4~1.7 μg/kg,不同基质的保健食品在3个添加水平(2.0、5.0和10.0 μg/kg)下的回收率为60.5%~116.3%(n=6),相对标准偏差(RSD)为6.8%~11.2%(n=6)。方法操作简单、耗时短、灵敏度高,满足现行法规要求,可实现保健食品中双酚类化合物的定性和定量测定。     

Simultaneous determination of water-soluble and fat-soluble synthetic colorants in foodstuff by high-performance liquid chromatography-diode array detection-electrospray mass spectrometry

An accurate method was developed for the simultaneous determination of water-Tartrazine, Amaranth, Ponceau 4R, Sunset Yellow FCF, and fat-Sudan (I-IV), synthetic soluble colorants in foodstuff. This method uses dimethylsulfoxide (DMSO) as the extraction solvent in the sample preparation process and high performance liquid chromatography (HPLC)-diode array detector (DAD)-electrospray mass spectrometry (ESI-MS), applying selected ion recording in positive/negative alternate mode to acquire mass spectral data, as the analytical technique. Linearity of around three orders in the magnitude of concentration was generally obtained. Detection and quantification limits of the investigated dyes, which were evaluated at signal to noise ratio of 3 for detection limit and 10 for quantification limit, were in the ranges of 0.01-4 and 0.03-11.2 ng, respectively. The recoveries of the eight synthetic colorants in four matrices ranged from 93.2 to 108.3%. Relative standard deviations of less than 8.2% were also achieved. This method has been applied successfully in the determination of water-soluble colorants in the soft drink and the delicious ginger, and fat-soluble dyes in chilli powders and chilli spices.     

Simultaneous Determination of Anthocyanin and Ponceau 4R in Drink Powders by Derivative Spectrophotometry and Partial Least-Squares Multivariate Spectrophotometric Calibration

Summary.  Two methods for the simultaneous determination of anthocyanin and ponceau 4R in drink powders by second derivative spectrophotometry and by partial least-squares multivariate spectrophotometric calibration are described. The procedures do not require any separation step. The methods were applied to determine both colorants in commercial gelatin powders; the results obtained are compared. Received September 7, 2000. Accepted (revised) November 20, 2000     

Determination of hydroxysafflor yellow A in rat plasma and tissues by high-performance liquid chromatography after oral administration of safflower extract or safflor yellow

A simple and reproducible HPLC method for quantification of hydroxysafflor yellow A (HSYA) in rat plasma and tissues after oral administration of safflower extract or safflor yellow (SY) was developed. Sample preparation was achieved by protein precipitation of plasma and tissue homogenates with three volumes of methanol. p-Hydroxybenzaldehyde was used as the internal standard (IS). HSYA and IS were separated on a Hypersil BDS-C(18) column with a gradient elution system composed of acetonitrile and aqueous acetic acid. UV detection was used at 320 nm. The calibration curves were linear in all matrices (r(2) > 0.999) in the concentration ranges 0.51-101.36 microg/mL for plasma, 12.27-2454.46 microg/g for intestines and 0.96-192.20 microg/g for lung. The intra-day and inter-day precision were all less than 12.5%, and the extract recovery was in the range 64.1-103.7% with RSD less than 15.6% for HSYA in all matrices. The method was used successfully to quantify HSYA in rat plasma and tissue samples to support a pharmacokinectic study.     

分散固相萃取/气相色谱-三重四极杆串联质谱法检测纸张中的20种芳香胺

建立了纸张中的20种芳香胺的分散固相萃取/气相色谱-三重四极杆串联质谱分析方法。纸张中的偶氮染料于(70±2)℃经预处理后还原为芳香胺,向反应后的悬浮液中先加入4 mL 10 mol/L氢氧化钠溶液,将pH值由弱酸性调至碱性,再加入0.5 mL的3内标(氘代萘、2,4,5-三氯苯胺和氘代蒽)工作溶液、10 mL的叔丁基甲醚,最后加入15 g无水硫酸钠除水,振摇40 min萃取芳香胺。萃取液经分散固相萃取试剂盒(d-SPE)进一步净化、离心后,取上层清液以气相色谱-三重四极杆串联质谱法(GC-MS/MS),在多反应离子监测(MRM)模式下检测,内标法定量。目标物在各自浓度范围内线性关系良好(r~20.99),在10、20、50 ng/mL 3个加标水平下的回收率为80.7%～128%,相对标准偏差(RSDs)为0.79%～6.5%,检出限(LOD)为0.05～2.1 ng/mL,定量下限(LOQ)为0.18～5.5 ng/mL。该方法简便快捷,灵敏度高,可用于纸张中芳香胺的快速检测。