Simultaneous determination of aspartame, cyclamate, saccharin and acesulfame-K in soft drinks and tabletop sweetener formulations by capillary electrophoresis with capacitively coupled contactless conductivity detection

Amperometric bienzymatic biosensor in flow injection analysis system for determination of aspartame in foods

An amperometric bienzymatic biosensor was developed for the determination of aspartame in a flow injection analysis (FIA) system, consisting of two enzyme reactor columns packed with immobilized α-chymotrypsin (CHY) and alcohol oxidase (AOX) beads and a hydrogen peroxide electrode, connected in series. The CHY and AOX were separately immobilized on glutaraldehyde (GA)-activated beads through covalent bonding. The biosensor fabrication and operational conditions were optimized. The optimal fabrication conditions were: 2% GA with 120 min activation time; and 250 U/mL CHY and 100 U/mL AOX, with 180 min enzyme immobilization time. The optimal operational conditions were a flow rate of 0.5 mL/min and pH 8.0 at room temperature. The developed biosensor showed linearity over the aspartame concentration range 0.01-1.2 mM, with a detection limit of 0.005 mM. The developed biosensor was satisfactorily applied for detecting aspartame in beverage samples without any excessive pretreatments.

A Coordination Polymer for the Fluorescence Turn-On Sensing of Saccharin, 2-Thiazolidinethione-4-carboxylic Acid, and Periodate

A luminescent 1D coordination polymer (CP) [Zn2L2(H2O)4]·H2O (1, H2L = 1-(4-carboxyphenyl)-1H-pyrazole-3-carboxylic acid) was prepared by a solvothermal method. 1 shows excellent fluorescence properties and has an obvious fluorescence "turn-on" phenomenon for saccharin (SAC), 2-thiazolidinethione-4-carboxylic acid (TTCA), and periodate (IO4-). Between 0 and 60 μM concentration range of SAC, the fluorescence enhancement efficiency (KEC) of 1 reaches 1.00 × 105 M-1 with the limit of detection (LOD) of 90 nM. 1 is the first CP-based sensing material for SAC detection. For TTCA detection, the KEC is 2.73 × 105 M-1 at the 25-80 μM concentration range, and the LOD is 33 nM, the lowest LOD among the sensors that detect TTCA at present. For IO4- ion detection, when the IO4- ion concentration ranges from 0 to 10 μM, the KEC is 2.34 × 105 M-1 and the LOD is as low as 39 nM. In order to better understand the sensing phenomenon, we also discuss in detail the sensing mechanisms for SAC, TTCA, and IO4- ions.

Simultaneous determination of nine high-intensity sweeteners in liquid and powder tabletop sweeteners

Government regulatory actions and public policies have been recently implemented in Brazil due to the excessive consumption of sugar. Therefore, it becomes relevant to determine the levels of high-intensity sweeteners in tabletop sweeteners consumed by the Brazilian population. Thus, an analytical method was developed and validated for the simultaneous determination of nine sweeteners (acesulfame potassium, aspartame, advantame, sodium cyclamate, neotame, saccharin, sucralose, stevioside, and rebaudioside A) by using ultra-high performance liquid chromatography coupled to mass spectrometry in tandem. The sample preparation encompassed only dilution steps. The method was validated taking into account the parameters of linearity, precision, accuracy, and matrix effects. The analytes were determined in two different batches of 21 commercial liquid and powder tabletop sweeteners available on the local market, totaling 42 samples. A minimum of one and a maximum of four sweeteners were found in the analyzed products and sweeteners that were not described on the label were not detected. It is expected that the established method can be used in monitoring programs and that the presented results can contribute to exposure assessments performed nationally.

Classification of Food Additives Using UV Spectroscopy and One-Dimensional Convolutional Neural Network

Food additives are utilized in countless food products available for sale. They enhance or obtain a specific flavor, extend the storage time, or obtain a desired texture. This paper presents an automatic classification system for five food additives based on their absorbance in the ultraviolet domain. Solutions with different concentrations were created by dissolving a measured additive mass into distilled water. The analyzed samples were either simple (one additive solution) or mixed (two additive solutions). The substances presented absorbance peaks between 190 nm and 360 nm. Each substance presents a certain number of absorbance peaks at specific wavelengths (e.g., acesulfame potassium presents an absorbance peak at 226 nm, whereas the peak associated with potassium sorbate is at 254 nm). Therefore, each additive has a distinctive spectrum that can be used for classification. The sample classification was performed using deep learning techniques. The samples were associated with numerical labels and divided into three datasets (training, validation, and testing). The best classification results were obtained using CNN (convolutional neural network) models. The classification of the 404 spectra with a CNN model with three convolutional layers obtained a mean testing accuracy of 92.38% ± 1.48%, whereas the mean validation accuracy was 93.43% ± 2.01%.

Rapid and sensitive quantification of cyclamate in beverages by miniature microplasma optical emission spectrometry

Most of the available methods for the quantification of cyclamate depend on laboratory instruments and their application in the field was limited. Herein, a simple and sensitive method was developed for the determination of cyclamate in beverage samples based on chemical vapor generation and miniature point discharge optical emission spectrometry (μPD-OES). The combination of headspace sampling and μPD-OES not only simplifies the separation process of cyclamate, improves sensitivity, and alleviates matrix interference but also eliminates the use of a bulky and expensive instrument. Under the optimal conditions, this method provided a limit of detection of 0.1 mg L^-1 comparable to or better than most reported methods. The method eventually was applied to 14 different beverages and cyclamate was found below the threshold set by Chinese Standards for Food Additives. The proposed method provides great potential for the field analysis of cyclamate in the supervision of food safety.

Determination of naphthenic acids in produced water by using microchip electrophoresis with integrated contactless conductivity detection

This study reports for the first time the use of a microchip electrophoresis (ME) device with integrated capacitively coupled contactless conductivity detection (C⁴D) to analyze naphthenic acids in produced water. A mixture containing 9-anthracenecarboxylic, 1-naphthoic, and benzoic acids was separated and detected using a running buffer composed of 10 mmol L^-1 carbonate buffer (pH = 10.2). The separation was achieved within ca. 140 s with baseline resolution greater than 2 and efficiency values ranging from 1.9 × 10⁵ to 2.4 × 10⁵ plates m^-1. The developed methodology provided linear correlation with determination coefficients greater than 0.992 for the concentration ranges between 50 and 250 µmol L^-1 for benzoic and 9-anthracenecarboxylic acids, and between 50 and 200 µmol L^-1 for 1-naphthoic acid. The achieved limit of detection values varied between 4.7 and 7.7 µmol L^-1. The proposed methodology revealed satisfactory repeatability with RSD values for a sequence of eight injections between 5.5 and 7.7% for peak areas and lower than 1% for migration times. In addition, inter-day precision was evaluated for sixteen injections (a sequence of four injections performed during four days), and the RSD values were lower than 11.5 and 4.9% for peak areas and migration time, respectively. Five produced water samples were analyzed, and it was possible to detect and quantify 9-anthracenecarboxylic acid. The concentrations ranged from 1.05 to 2.24 mmol L^-1 with recovery values between 90.8 and 96.0%. ME-C⁴D demonstrated satisfactory analytical performance for determining naphthenic acids in produced water for the first time, which is useful for petroleum or oil industry investigation.

HPTLC screening of saccharin in beverages by densitometry quantification and SERS confirmation

As a widely used artificially synthesized sweetener, saccharin faced numerous disputes associated with food safety. Therefore, its fast analysis in food is of crucial importance. In this study, an analytical method for the fast and reliable screening of saccharin in various beverages was established and validated, by combining HPTLC with densitometry and surface enhanced Raman spectroscopy. The diluted sample liquid was directly sprayed and separated on a silica gel plate using a mixture of ethyl acetate and acetic acid in the ratio of 9 : 1 (v/v) as the mobile phase. The separation realized full isolation of the analyte from background noises. Then, a densitometry analysis in the absorption–reflection mode (working wavelength 230 nm) was optimized to obtain quantitative data, showing a good linearity in the range of 40–200 ng per band (R² = 0.9988). The limits of detection and quantification were determined to be 6 and 20 ng per band, respectively, which were equal to 6 and 20 mg kg⁻¹. The quantitative results also displayed satisfactory accuracy and precision, with a spike-recovery rate within 87.75–98.14% (RSD <5.13%). As a cost-efficient tool for confirmation, surface enhanced Raman spectroscopy was employed to profile the molecular fingerprint of the analyte eluted from the plate layer. Under optimized conditions (785 nm laser as the excitation light and silver nanoparticle loaded glass fiber paper as the active substrate), the elution of the saccharin band exhibited stable and sensitive surface enhanced Raman spectroscopy signals. This study demonstrated that HPTLC could be a versatile platform for food analysis, with outstanding simplicity and cost-efficiency.

As a widely used artificially synthesized sweetener, saccharin faced numerous disputes associated with food safety.

Host–guest sensing towards sodium cyclamate based on a cationic pillar[6]arene reduced graphene nano-composite

A competitive fluorescence sensing for the detection of sodium cyclamate based on a cationic water-soluble pillar[6]arene graphene nano-composite.

Capillary and microchip electrophoresis with contactless conductivity detection for analysis of foodstuffs and beverages

The paper provides a comprehensive survey of the use of capillary and microchip electrophoresis in combination with contactless conductivity detection (C⁴D) for the analysis of drinking water, beverages and foodstuffs. The introduction sets forth the fundamentals of conductivity detection anddescribes an axialC⁴Dversion. There is also a detailed discussion of the determination of inorganic ions, organic acids, fatty acids, amino acids, amines, carbohydrates, foreign substances and poisons from the standpoint of separation conditions, sample treatment and detection limits. Special attention is paid to the analysis of foodstuffs at microchips with emphasis on the employed material and connection of the microchip with the C⁴D. The review attempts to draw attention to modern trends, such as dual-opposite injection, field-enhanced sample injection, electromembrane extraction and on-line combination of microdialysis with CE. CE/C⁴D is characterised by high universality, high speed of analysis, simple sample preparation, small consumption of sample and other chemicals.

Analytical Methods for Determination of Non-Nutritive Sweeteners in Foodstuffs

Sweeteners have been used in food for centuries to increase both taste and appearance. However, the consumption of sweeteners, mainly sugars, has an adverse effect on human health when consumed in excessive doses for a certain period, including alteration in gut microbiota, obesity, and diabetes. Therefore, the application of non-nutritive sweeteners in foodstuffs has risen dramatically in the last decade to substitute sugars. These sweeteners are commonly recognized as high-intensity sweeteners because, in a lower amount, they could achieve the same sweetness of sugar. Regulatory authorities and supervisory agencies around the globe have established the maximum amount of these high-intensity sweeteners used in food products. While the regulation is getting tighter on the market to ensure food safety, reliable analytical methods are required to assist the surveillance in monitoring the use of high-intensity sweeteners. Hence, it is also necessary to comprehend the most appropriate method for rapid and effective analyses applied for quality control in food industries, surveillance and monitoring on the market, etc. Apart from various analytical methods discussed here, extraction techniques, as an essential step of sample preparation, are also highlighted. The proper procedure, efficiency, and the use of solvents are discussed in this review to assist in selecting a suitable extraction method for a food matrix. Single- and multianalyte analyses of sweeteners are also described, employing various regular techniques, such as HPLC, and advanced techniques. Furthermore, to support on-site surveillance of sweeteners’ usage in food products on the market, non-destructive analytical methods that provide practical, fast, and relatively low-cost analysis are widely implemented.

Quantification of artificial sweeteners in alcoholic drinks using direct analysis in real-time QTRAP mass spectrometry

Artificial sweeteners have been widely used as replacements for sugars in foods. Rapid determination of artificial sweeteners contained in various foods are highly desirable for the routine analysis. Here, we report a robust approach based on direct analysis in real time coupled with QTRAP mass spectrometry to screen and quantitate simultaneously seven artificial sweeteners, including aspartame, saccharin, acesulfame-K, neotame, sucralose, cyclamate and alitame in alcoholic drinks. The detection method merely involved a simple sample pretreatment process, with a good linearity, low limit of quantification, satisfied recovery and relative standard deviation for each target compound. More importantly, the approach is highly sensitive and accurate in monitoring the seven artificial sweeteners in whisky, Chinese liquors, beer and wines obtained from the supermarket. The results demonstrated that the approach described here could be suitable for large-scale application in routine quality control analysis of artificial sweeteners.

Artificial sweeteners in non-alcoholic beverages: Occurrence and exposure estimation of the Portuguese population

Artificial sweeteners such as acesulfame-potassium (ACE-K). saccharin (SAC), and aspartame (ASP), play a vital role in the food industry. Despite apparent benefits, several studies report adverse reactions on consumers. EFSA is currently re-evaluating several individual sweeteners, including ASP, Ace-K and SAC that shall be completed by 31 December 2020. Our goal was to evaluate, by liquid chromatography with ultraviolet detection (LC-UV), their levels in non-alcoholic beverages from the Portuguese market (soft drinks, sport drinks, energy drinks, and nectars), and estimate the exposure of the Portuguese adolescent/adult population. ACE-K was found in 85.7% of the samples, in mean levels of 97.4 mg/L. ASP and SAC, detected in 37.5% and 33.9% of the samples, were found in averages of 161.5 and 55.0 mg/L, respectively. The maximum limits set for ASP were exceeded in one energy drink. SAC exceeded the maximum permitted level (MPL) level in 3 soft drinks based on tea extracts. In 4 samples SAC was found but not mentioned in the label, and in one of these samples exceeded the MPL. The estimated daily intake (EDI), calculated in mg per kilogram of body weight per day, of ACE-K, SAC and ASP was found to be below the acceptable daily intake (ADI), both for Portuguese adolescents and adult population. Traditional soft drinks accounted for the highest EDIs representing 1.8%, 2.3% and 0.6% for ACE-K, SAC and ASP, respectively, of the ADI. Considering the previous report in Portugal it is observed that the population is currently exposed to a greater amount of artificial sweeteners, which may indicate a trend for more artificial sweeteners' usage in order to reduce sugar intake.

Determining High-Intensity Sweeteners in White Spirits Using an Ultrahigh Performance Liquid Chromatograph with a Photo-Diode Array Detector and Charged Aerosol Detector

In China, white spirit is not only an alcoholic drink but also a cultural symbol. A novel and accurate method for simultaneously determining nine sweeteners (most authorized for use in China) in white spirits by ultrahigh performance liquid chromatography (UHPLC) with a photo-diode array detector (PDA) and charged aerosol detector (CAD) was developed. The sweeteners were acesulfame, alitame, aspartame, dulcin, neotame, neohesperidine dihydrochalcone, saccharin, sodium cyclamate, and sucralose. The sweeteners were separated within 16 min using a BEH C18 column and linear gradient-elution program. The optimized method allowed low concentrations (micrograms per gram) of sweeteners to be simultaneously detected. The CAD gave good linearities (correlation coefficients > 0.9936) for all analytes at concentrations of 0.5 to 50.0 μg/g. The limits of detection were 0.16 to 0.77 μg/g. Acesulfame, dulcin, neohesperidine dihydrochalcone, and saccharin were determined using the PDA detector, which gave correlation coefficients > 0.9994 and limits of detection of 0.16 to 0.22 μg/g. The recoveries were 95.1% to 104.9% and the relative standard deviations were 1.6% to 3.8%. The UHPLC-PDA-CAD method is more convenient and cheaper than LC-MS/MS methods. The method was successfully used in a major project called “Special Action against Counterfeit and Shoddy white spirits” and to monitor risks posed by white spirits in China.

Organic-Inorganic Nanohybrid Electrochemical Sensors from Multi-Walled Carbon Nanotubes Decorated with Zinc Oxide Nanoparticles and In-Situ Wrapped with Poly(2-methacryloyloxyethyl ferrocenecarboxylate) for Detection of the Content of Food Additives

An electrochemical sensor for detection of the content of aspartame was developed by modifying a glassy carbon electrode (GCE) with multi-walled carbon nanotubes decorated with zinc oxide nanoparticles and in-situ wrapped with poly(2-methacryloyloxyethyl ferrocenecarboxylate) (MWCNTs@ZnO/PMAEFc). MWCNTs@ZnO/PMAEFc nanohybrids were prepared through reaction of zinc acetate dihydrate with LiOH·H2O, followed by reversible addition-fragmentation chain transfer polymerization of 2-methacryloyloxyethyl ferrocenecarboxylate, and were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM), scanning electron microscope (SEM), and transmission electron microscope (TEM) techniques. The electrochemical properties of the prepared nanohybrids with various composition ratios were examined by cyclic voltammetry (CV), and the trace additives in food and/or beverage was detected by using differential pulse voltammetry (DPV). The experimental results indicated that the prepared nanohybrids for fabrication of electrochemical modified electrodes possess active electroresponse, marked redox current, and good electrochemical reversibility, which could be mediated by changing the system formulations. The nanohybrid modified electrode sensors had a good peak current linear dependence on the analyte concentration with a wide detection range and a limit of detection as low as about 1.35 × 10-9 mol L-1, and the amount of aspartame was measured to be 35.36 and 40.20 µM in Coke zero, and Sprite zero, respectively. Therefore, the developed nanohybrids can potentially be used to fabricate novel electrochemical sensors for applications in the detection of beverage and food safety.

Simultaneous determination of three sulfanilamide artificial sweeteners in foodstuffs by capillary electrophoresis coupled with contactless conductivity detection based on porous aromatic frameworks enhanced solid phase extraction

In this paper, a simple and easy method of solid phase extraction (SPE) followed by capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection (C4D) is evaluated as a novel approach for the simultaneous determination of acesulfame-K (ACE), sodium saccharin (SAC), and sodium cyclamate (CYC) in foodstuffs without derivatization. To reduce the complex matrix interference resulting from the constituents of samples and enriched targets, porous aromatic frameworks (PAFs) enhanced SPE, a suitable sample pretreatment procedure, was introduced. Several factors affecting extraction efficiency and electrophoretic separation were investigated. Additionally, the interaction mechanisms between the host (PAF-6) and guests (ACE, SAC, and CYC) were studied. Under the optimum conditions, three sulfanilamide artificial sweeteners were baseline separated within 8 min, exhibiting a linear calibration over two orders of magnitude (R2 > 0.995). The limits of detection (LOD) and quantification (LOQ) were considered better than those usually obtained by CE with ultraviolet and C4D detection. The proposed SPE–CE–C4D method has been successfully applied to analyse beverage samples and candied fruits with recoveries in the range of 78.89%–92.00%.

Simultaneous extraction and analysis of preservatives and artificial sweeteners in juices by salting out liquid-liquid extraction method prior to ultra-high performance liquid chromatography

A novel and fast salting out liquid-liquid extraction method was developed for simultaneous determination of food additives with different polarities in juices. Chromatographic separation was achieved in less than 6 min using Acquity UPLC BEH C 18 (100 mm × 2.1 mm d.i. × 1.7 µm) column with ammonium acetate with 0.01% of trifluoroacetic acid as eluent A and acetonitrile as eluent B at a flow rate of 0.2 mL min^-1. The main factors affecting the extraction efficiency were optimized. The method was validated applying accuracy profile based on total error. The extraction recoveries ranged from 84.97 to 122%. Relative standard deviation ranged from 1.24 to 7.99% for intraday assay and from 1.69 to 9.16% for intermediate precision. The limits of detection for five food additives were from 0.3 to 1.42 µg mL^-1. The method was successfully applied to 47 samples of juices from nine brands.

On-cartridge derivatisation using matrix solid phase dispersion for the determination of cyclamate in foods

A novel method for determination of sodium cyclamate in foods was developed. In this method, a syringe was loaded with the homogeneous mixture of the sample, KMnO₄ powder and silica dispersant and used as a matrix solid phase dispersion (MSPD) reactor. As the reactor was infiltrated with small amounts of concentrated HCl, cyclamate was converted to 2-chlorocyclohexanone quickly and effectively within 5 min and determined by HPLC on a reversed-phase column using UV detection at a wavelength of 310 nm. Comparing with the traditional derivatisation in solution, the better clean-up was provided using on-cartridge derivatisation of MSPD, and much time, labor, and expense were saved. The results showed good linearity (r² = 0.9998) over the concentration range of 1-500 mg/L. The limit of detection (LOD) and limits of quantification (LOQ) of the cyclamate were 0.3 mg/L and 1 mg/L respectively. The recoveries ranged from 91.6% to 101.3% with the relative standard deviations (RSDs) in the range of 2.5%-4.3%.

Simultaneous determination of aspartame, cyclamate, saccharin and acesulfame-K in powder tabletop sweeteners by FT-Raman spectroscopy associated with the multivariate calibration: PLS, iPLS and siPLS models were compared

For the first time, a procedure for simultaneous determination of the main artificial sweeteners, aspartame (ASP), cyclamate (CYC), saccharin (SAC), and acesulfame-K (ACSK) by a spectroscopic method associated with the multivariate calibration is proposed. These analytes were quantified in tabletop sweeteners samples using FT-Raman spectroscopy. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used as reference method. Partial least squares (PLS), interval PLS (iPLS), and synergism PLS (siPLS) methods were evaluated in a comparative study where the selected interval models presented better results. Multivariate regression models, such as PLS, iPLS and siPLS were built and the lower root mean square errors for prediction (RMSEP) found were 0.027-0.031% w/w, 0.316-0.363% w/w, 0.082-0.184% w/w, and 0.040-0.049% w/w to ASP, CYC, SAC, and ACSK, respectively. The coefficient of determination for prediction (R²_p) varied between 0.978 and 0.979, 0.969-0.977, 0.952-0.994, and 0.959-0.965 for ASP, CYC, SAC and ACSK, respectively. The analysis of model's residues was made by bias and permutation tests to evaluate systematic and trend errors. The selected intervals by iPLS and siPLS were evaluated and the bands related to the vibrational modes of the analytes were assigned with the aid of density functional theory calculations (DFT).

Sensitive simultaneous determination of three sulfanilamide artificial sweeters by capillary electrophoresis with on-line preconcentration and contactless conductivity detection

A sensitive method followed by capillary electrophoresis with on-line perconcentration and capacitively coupled contactless conductivity detection (CE-C(4)D) was evaluated as a novel approach for the determination of three sulfanilamide artificial sweeteners (acesulfame-K, sodium saccharin and sodium cyclamate) in beverages. The on-line preconcentration technique, namely field-amplified sample injection, coupled with CE-C(4)D were successfully developed and optimized. The separation was achieved within 10 min under the following conditions: an uncoated fused-silica capillary (45 cm × 50 μm i.d., Leff=40 cm), 20 mmol L(-1) HAc as running buffer, separation voltage of -12 kV, electrokinetic injection of -11 kV × 8 s. The detection limits of acesulfame-K, sodium saccharin and sodium cyclamate were 4.4, 6.7 and 8.8 μg L(-1), respectively. The relative standard deviation varied in the range of 3.0-5.0%. Results of this study show a great potential method for the fast screening of these artificial sweeteners contents in commercial beverages.

Determination of eight artificial sweeteners and common Stevia rebaudiana glycosides in non-alcoholic and alcoholic beverages by reversed-phase liquid chromatography coupled with tandem mass spectrometry

The method for the determination of acesulfame-K, saccharine, cyclamate, aspartame, sucralose, alitame, neohesperidin dihydrochalcone, neotame and five common steviol glycosides (rebaudioside A, rebaudioside C, steviol, steviolbioside and stevioside) in soft and alcoholic beverages was developed using high-performance liquid chromatography and tandem mass spectrometry with electrospray ionisation (HPLC-ESI-MS/MS). To the best of our knowledge, this is the first work that presents an HPLC-ESI-MS/MS method which allows for the simultaneous determination of all EU-authorised high-potency sweeteners (thaumatin being the only exception) in one analytical run. The minimalistic sample preparation procedure consisted of only two operations; dilution and centrifugation. Linearity, limits of detection and quantitation, repeatability, and trueness of the method were evaluated. The obtained recoveries at three tested concentration levels varied from 97.0 to 105.7%, with relative standard deviations lower than 4.1%. The proposed method was successfully applied for the determination of sweeteners in 24 samples of different soft and alcoholic drinks.

TDS exposure project: relevance of the total diet study approach for different groups of substances

A method to validate the relevance of the Total Diet Study (TDS) approach for different types of substances is described. As a first step, a list of >2800 chemicals classified into eight main groups of relevance for food safety (natural components, environmental contaminants, substances intentionally added to foods, residues, naturally occurring contaminants, process contaminants, contaminants from packaging and food contact materials, other substances) has been established. The appropriateness of the TDS approach for the different substance groups has then been considered with regard to the three essential principles of a TDS: representativeness of the whole diet, pooling of foods and food analyzed as consumed. Four criteria were considered for that purpose (i) the substance has to be present in a significant part of the diet or predominantly present in specific food groups, (ii) a robust analytical method has to be available to determine it in potential contributors to the dietary exposure of the population, and (iii) the dilution impact of pooling and (iv) the impact of everyday food preparation methods on the concentration of the substance are assessed. For most of the substances the TDS approach appeared to be relevant and any precautions to be taken are outlined.

Recent developments in capillary and microchip electroseparations of peptides (2011-2013)

The review presents a comprehensive survey of recent developments and applications of capillary and microchip electroseparation methods (zone electrophoresis, ITP, IEF, affinity electrophoresis, EKC, and electrochromatography) for analysis, isolation, purification, and physicochemical and biochemical characterization of peptides. Advances in the investigation of electromigration properties of peptides, in the methodology of their analysis, including sample preseparation, preconcentration and derivatization, adsorption suppression and EOF control, as well as in detection of peptides, are presented. New developments in particular CE and CEC modes are reported and several types of their applications to peptide analysis are described: conventional qualitative and quantitative analysis, determination in complex (bio)matrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid, sequence and chiral analysis, and peptide mapping of proteins. Some micropreparative peptide separations are shown and capabilities of CE and CEC techniques to provide relevant physicochemical characteristics of peptides are demonstrated.

Determination of neotame in non-alcoholic beverage by capillary zone electrophoresis

BACKGROUND

Neotame (NEO) is a new artificial sweetener approved as a food additive in many countries. The present method for the determination of NEO in various foodstuffs is high-performance liquid chromatography (HPLC). There are no reports on the determination of NEO in foods by capillary zone electrophoresis (CZE). Therefore a simple and rapid method to determine NEO is desired for quality control.

RESULTS

A CZE method combined with solid phase extraction was developed for the determination of NEO in non-alcoholic beverage. The optimum separation conditions obtained were 20 mmol L(-1) sodium borate buffer, pH 8, 25 kV applied voltage, 5 s hydrodynamic injection at 30 mbar and ultraviolet detection at 191 nm. The calibration curve showed good linearity (R(2) = 1.000) in the range 0.5-100 µg mL(-1) , and the limit of detection was 0.118 µg mL(-1) . The method was successfully applied to the determination of NEO in two kinds of beverage with migration time less than 5 min, relative standard deviation (n = 3) less than 2% and recoveries ranging from 90 to 95%.

CONCLUSION

The proposed CZE method has the advantages of shorter analysis time and lower cost compared with HPLC, indicating that it may be a good alternative to the HPLC method.

Determination of artificial sweeteners by capillary electrophoresis with contactless conductivity detection optimized by hydrodynamic pumping

The common sweeteners aspartame, cyclamate, saccharin and acesulfame K were determined by capillary electrophoresis with contactless conductivity detection. In order to obtain the best compromise between separation efficiency and analysis time hydrodynamic pumping was imposed during the electrophoresis run employing a sequential injection manifold based on a syringe pump. Band broadening was avoided by using capillaries of a narrow 10 μm internal diameter. The analyses were carried out in an aqueous running buffer consisting of 150 mM 2-(cyclohexylamino)ethanesulfonic acid and 400 mM tris(hydroxymethyl)aminomethane at pH 9.1 in order to render all analytes in the fully deprotonated anionic form. The use of surface modification to eliminate or reverse the electroosmotic flow was not necessary due to the superimposed bulk flow. The use of hydrodynamic pumping allowed easy optimization, either for fast separations (80s) or low detection limits (6.5 μmol L(-1), 5.0 μmol L(-1), 4.0 μmol L(-1) and 3.8 μmol L(-1) for aspartame, cyclamate, saccharin and acesulfame K respectively, at a separation time of 190 s). The conditions for fast separations not only led to higher limits of detection but also to a narrower dynamic range. However, the settings can be changed readily between separations if needed. The four compounds were determined successfully in food samples.

Recent progress for capillary electrophoresis with electrochemical detection

Capillary electrophoresis (CE) is an attractive technique in separation science because of its high separation performance, short analysis time and low cost. Electrochemical detection (EC) is a powerful tool for CE because of its high sensitivity. In this review, developments of CE-EC from 2008 to August, 2011 are reviewed. We choose papers of innovative and novel results to demonstrate the newest and most important progress in CE-EC.

Rapid analysis of cyclamate in foods and beverages by gas chromatography-electron capture detector (GC-ECD)

A rapid method for determination of sodium cyclamate in foods and beverages was developed. Sodium cyclamate was converted to N,N-dichloridecyclohexylamine by reaction with sodium hypochlorite under acid condition. N,N-dichloridecyclohexylamine was subsequently extracted by n-hexane and determined by gas chromatography. Conditions such as derivatization time, the concentration of sodium hypochlorite and sulphuric acid were optimised. Amino acids, aliphatic amines, and food additives such as preservatives, dyes and sweeteners showed no interference for quantification of cyclamate. The correlation coefficient of calibration curve was 0.9993 in the range of 5.0-250mg/L. The limits of detection (LOD) and limits of quantification (LOQ) were calculated as three or ten times the signal-to-noise ratio (S/N), respectively. The LOD and LOQ for yellow wine and fruit juice were 0.05 and 0.2mg/L, respectively. The LOD and LOQ for cake and preserved fruit were 0.25 and 0.8mg/kg, respectively. The intra-day and inter-day RSD were 0.28% and 1.1% (n=5), respectively. The method was successfully applied for determination of cyclamate in yellow wine, cake, fruit juice and preserved fruit. This method was simple, fast, and sensitive. It was suitable for the determination of cyclamate in foods and beverages for safety and quality control inspections.

Recent advances in applications of capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C⁴D): an update

Capillary electrophoresis with a capacitively contactless conductivity detector (CE-C⁴D) is becoming a significant useful technique for the analysis of analytes in various fields such as pharmaceutical, biomedical, food and environmental. This review is an update describing the recent developments in the application of CE with a C⁴D detector.