Water-soluble Food Dyes Research Articles

A comparative review on High-Performance Liquid Chromatography (HPLC), Ultra Performance Liquid Chromatography (UPLC) & High-Performance Thin Layer Chromatography (HPTLC) with current updates

Abstract Any chosen analytical method should be subtle, precise, fast and exact to begin the guarantee that the material used in the manufacturing is free of unsolicited impurity, the existence of which may vary the safety and effectiveness of the drug product. The techniques of HPLC and UPLC have established their part in pharmaceutical cleaning validation. High-Performance Liquid Chromatography (HPLC) is the main pharmaceutical and biomedical analysis approach utilized today because it generates highly efficient separations, and in most circumstances, it provides high detection sensitivity. Applying the HPLC method has several advantages compared to other methods, among others, specificity, rapidity, accuracy, precision, and the ease of automation. Due to the aforementioned, most drugs in a multi-component dosage form can be analyzed. Ultra-Performance Liquid Chromatography (UPLC) is a modern-day technique that gives a new track for liquid chromatography. UPLC provides the user with speed of application, resolution and sensitivity. The quantification and separation in UPLC are done under very high pressure (up to 100M Pa). High-Performance Thin Layer Chromatography (HPTLC) has improved and innovative separation efficacy and detection limits. It is a cultured and automated form of Thin Layer Chromatography (TLC) and is based on the use of an optimized silica gel 60 with a significantly smaller particle size than which is used for TLC. The previously stated analytical methods are employed for purity control of chemicals, steroids, pesticides, and water analysis, water-soluble food dyes, vitamins, pesticides in vegetables, fruits, and other foodstuffs. The current updates in the techniques allow us to understand the increased utilization of these methods in the current eras.

Water-soluble food dye of Allura Red as a tracer to determine the spray deposition of pesticide on target crops.

Quantification of spray deposition on a target crop is of vital importance to optimize pesticide application. In traditional determinations of spray deposition, a large amount of organic solvent is used to extract pesticides from the target crops. In this study, a water-soluble food dye of Allura Red was developed as a tracer to determine pesticide spray deposition on a rice target crop. The addition of Allura Red does not obviously alter the physicochemical properties of pesticides (viscosity, density and surface tension) and droplet spectra. An ultra-performance liquid chromatography (UPLC) analytical method was developed and validated to determine the deposition amount of Allura Red on rice plants. Method accuracy and precision for Allura Red were found to be satisfactory with recoveries of 96.07% to 107.48%. To validate the method, comparative deposition analyses were carried out using representative systematic and non-systematic pesticides (nitenpyram and chlorothalonil) under the same spraying scenarios using a Potter spray tower. Allura Red and pesticides showed comparable deposition under the same application conditions with ratios from 0.98 to 1.21. A field trial using an unmanned aerial vehicle sprayer further indicated that the deposition rates for Allura Red and nitenpyram on rice seedling were 13.04% and 11.07%, with corresponding relative standard deviation values (n = 5) of 16.39% and 18.79%. A laboratory test and field trial confirmed that the developed method of using Allura Red as a tracer for spray deposition assessment is feasible and practicable. © 2019 Society of Chemical Industry.

Lemon yellow #15 a new highly stable, water soluble food colorant from the peel of Citrus limon

To provide stable and low-cost naturally derived yellow pigments, a variety of food byproducts were evaluated and the constituents of lemon peel have emerged yielding a highly promising natural product with applications as a food dye. Here we report a new, highly stable and water soluble food dye called yellow #15 from the ethanol extract of the zest of Citrus limon. The structure of lemon yellow #15 was carefully assigned on the basis of spectroscopic data, including 1D and 2D NMR spectroscopy, and the absolute configuration was established by comparison of the experimental CD with calculated electronic circular dichroism (ECD) spectral data. CIELAB values and Delta CIELAB were measured and revealed this new water-soluble pigment has superior light stability relative to other natural products used as food dyes.

Performance of Electropun Polyacrylonitrile Nanofibrous Phases, Shown for the Separation of Water-Soluble Food Dyes via UTLC-Vis-ESI-MS.

Research in the miniaturization of planar chromatography led to various approaches in manufacturing ultrathin-layer chromatography (UTLC) layers of reduced thickness (<50 µm) along with smaller instrumentation, as targeted in Office Chromatography. This novel concept merges 3D print & media technologies with miniaturized planar chromatography to realize an all-in-one instrument, in which all steps of UTLC are automated and integrated in the same tiny device. In this context, the development of electrospun polyacrylonitrile (PAN) nanofiber phases was investigated as well as its performance. A nanofibrous stationary phase with fiber diameters of 150–225 nm and a thickness of ca. 25 µm was manufactured. Mixtures of water-soluble food dyes were printed on it using a modified office printer, and successfully separated to illustrate the capabilities of such UTLC media. The separation took 8 min for 30 mm and was faster (up to a factor of 2) than on particulate layers. The mean hRF values ranging from 25 to 90 for the five food dyes were well spread over the migration distance, with an overall reproducibility of 7% (mean %RSD over 5 different plates for 5 dyes). The individual mean plate numbers over 5 plates ranged between 8286 and 22,885 (mean of 11,722 over all 5 dyes). The single mean resolutions RS were between 1.7 and 6.5 (for the 5 food dyes over 5 plates), with highly satisfying reproducibilities (0.3 as mean deviation of RS). Using videodensitometry, different amounts separated in parallel led to reliable linear calibrations for each dye (sdv of 3.1–9.1% for peak heights and 2.4–9.3% for peak areas). Coupling to mass spectrometry via an elution head-based interface was successfully demonstrated for such ultrathin layers, showing several advantages such as a reduced cleaning process and a minimum zone distance. All these results underline the potential of electrospun nanofibrous phases to succeed as affordable stationary phase for quantitative UTLC.

Rapid evaporation-driven chemical pre-concentration and separation on paper

Airflow-enhanced evaporation is investigated as a method for rapid chemical preconcentration on a thin porous substrate. The mechanism is described by combining 1D models of capillary rise, chromatography, and pervaporation concentration. It is shown that the effective length of the column can be shorter than its actual length, allowing concentrate to be held at a stagnation point and then released for separation, and that the Péclet number, which determines the concentration performance, is determined only by the substrate properties. The differential equations are solved dynamically, and it is shown that faster concentration can be achieved during capillary filling. Experiments are carried out using chromatography paper in a ducted airflow, and concentration is quantified by optical imaging of water-soluble food dyes. Good agreement with the model is obtained, and concentration factors of ≈100 are achieved in 10 min using Brilliant Blue FCF. Partial separation of Brilliant Blue from Tartrazine is demonstrated immediately following concentration, on a single unpatterned substrate. The mechanism may provide a method for improving the sensitivity of lab-on-paper devices.

Microfabrication, separations, and detection by mass spectrometry on ultrathin-layer chromatography plates prepared via the low-pressure chemical vapor deposition of silicon nitride onto carbon nanotube templates

Microfabrication of ultrathin-layer chromatography (UTLC) plates via conformal deposition of silicon nitride by low-pressure chemical vapor deposition onto patterned carbon nanotube (CNT) scaffolds was demonstrated. After removal of the CNTs and hydroxylation, the resulting UTLC phase showed no expansion or distortion of their microfeatures and the absence/reduction of remaining nitrogenic species. Developing time of a mixture of lipophilic dyes on this UTLC plates was 86% shorter than on high-performance thin-layer chromatography (HPTLC) plates. A water-soluble food dye mixture was also separated resulting in low band broadening and reduced developing time compared to HPTLC. For the latter example, mobile phase optimization on a single UTLC plate consisted of 14 developments with different mobile phases, each preceded by a plate prewashing step. The same plate was again reused for additional 11 separations under varying conditions resulting in a development procedure with a mean separation efficiency of 233,000theoretical plates/m and a reduced mobile phase consumption of only 400μL. This repeated use proved the physical robustness of the ultrathin layer and its resistance to damage. The layer was highly suited for hyphenation to ambient mass spectrometry, including desorption electrospray ionization (DESI) mass spectrometry imaging and direct analysis in real time (DART) mass spectrometry.

The effects of the forward speed and air volume of an air-assisted sprayer on spray deposition in tendone trained vineyards

This paper reports the results of spray application trials in a tendone trained vineyard in order to evaluate the influence of forward speed and air volume on the foliar deposition of plant protection products (PPPs), maintaining roughly constant the volume applied. The trials used an air-assisted sprayer with a centrifugal fan and 4+4 adjustable fan-shaped diffusers, each with a nozzle-holder group. A full factorial experimental design was implemented, with three forward speeds and two airflow rates, organised with a randomised complete block design including three replicates. In order to consider the influence of canopy development, the tests (one spray application for each replicate of a mixture containing a water-soluble food dye as a tracer) were replicated during two phenological stages: i) the end of flowering; and ii) berry touch. Leaves were picked at random from the canopy after each spray treatment, and foliar PPP deposition was evaluated using a spectrophotometer. This analysis of foliar deposition showed that the airflow rates produced by the fan were unsuitable for the dense canopy typical of this type of vineyard. However, the special shape of the diffusers may make this sprayer effective if the main objective of pesticide applications in tendone trained table grape vineyards is to control bunch diseases.

The effects of the forward speed and air volume of an air-assisted sprayer on spray deposition in tendone trained vineyards

This paper reports the results of spray application trials in a tendone trained vineyard in order to evaluate the influence of forward speed and air volume on the foliar deposition of plant protection products (PPPs), maintaining roughly constant the volume applied. The trials used an air-assisted sprayer with a centrifugal fan and 4+4 adjustable fan-shaped diffusers, each with a nozzle-holder group. A full factorial experimental design was implemented, with three forward speeds and two airflow rates, organised with a randomised complete block design including three replicates. In order to consider the influence of canopy development, the tests (one spray application for each replicate of a mixture containing a water-soluble food dye as a tracer) were replicated during two phenological stages: i) the end of flowering; and ii) berry touch. Leaves were picked at random from the canopy after each spray treatment, and foliar PPP deposition was evaluated using a spectrophotometer. This analysis of foliar deposition showed that the airflow rates produced by the fan were unsuitable for the dense canopy typical of this type of vineyard. However, the special shape of the diffusers may make this sprayer effective if the main objective of pesticide applications in tendone trained table grape vineyards is to control bunch diseases.

Rapid detection of ciprofloxacin effects on Fusarium graminearum and F. avenaceum cells in modulating environmental pH using a reactive, non-toxic food-dye indicator

The objective of the study was to assess the effect of ciprofloxacin antibiotic on the physiological or phenotypic characteristics of food-borne toxigenic Fusarium graminearum and F. avenaceum molds under in vitro conditions. In the presence of ciprofloxacin, Fusarium mycelia growth and morphology were altered based on the antibiotic concentration range used. Results showed that ciprofloxacin in concentrations ≥40 μg/mL induced chlamydospore formation in Fusaria and as such, this antibiotic should be considered as an important abiotic stress factor and growth inhibitor. A novel method was investigated to correlate chlamydospore formation with the colour changes observed in FD&C Green Number 3, a common water soluble food dye. The antibiotic-treated F. graminearum and F. avenaceum isolates produced chamydospores, which in turn altered environmental pH with concomitant changes in the colour and intensity of the dye. The colour changes observed as a function of environmental pH were supported by instrumental methods (pH meter and spectroscopy), and a commercial pH indicator (thymol blue) results. In conclusion, we propose that FD&C Green Number 3 can be used as an accurate indicator for the rapid assessment of Fusarium molds when grown on ciprofloxacin antibiotic-containing substrate. Special emphasis should be given to an indirect risk assessment of antibiotic effects on toxic molds.

Reversed-phase thin-layer chromatography of some foodstuff dyes

The chromatographic behavior of nine frequently used water-soluble food dyes has been studied by TLC on RP-18 silica gel. Reversed-phase chromatographic separations were performed with mobile phases containing ammonium sulfate and water with ethanol or acetone as organic modifiers. The effect of mobile phase composition on retention, and the selectivity of the chromatographic systems, are discussed, and on the basis of the results obtained separation mechanisms are proposed. It was established that ammonium sulfate as a component of the mobile phase significantly increased the reversed-phase behavior of the chromatographic systems used.

An exploration of the potential use of a CCD camera for absorption spectroscopy in scattered light at the rainbow

The advent of the CCD camera has made it possible to record light intensity as a function of two dimensions. In this paper, we have explored the camera's potential to measure spectra in scattered light at the rainbow by recording the intensity as a function of angle and wavelength. To this end, white light from a xenon arc lamp was scattered from water sprays containing various concentrations of water-soluble food dyes. Comparisons were made with theoretical spectra calculated using Mie theory Qualitatively agreement was excellent. Quantitatively agreement was reasonable, but there were some discrepancies as yet to be explained. Although the main rainbow is insensitive to the particle size distribution, if concentration of the absorbing species is to be recovered accurately an independent means of determining the particle sizes will be necessary.

Influence of Spray Application Parameters on Deposition in an Asparagus Crop

A commercial air-assisted sprayer was tested in asparagus crop using a water-soluble food dye as a tracer. The machine had been modified by lowering the nozzles and the air outlets by 20 cm, in order to match more close by the geometry of the asparagus crop canopies and to improve deposition at the base of the stems. Several tests were performed to investigate how deposition was affected by various treatments, including: the number, position and size of the nozzles; the spray volume rate; the presence or absence of air assistance; the spray output angle, relative to the travel direction; and the forward speed. The most uniform deposition was obtained with: four nozzles per side (the lowest at a height of 46 cm from the ground), directed horizontally; an air flow rate of 6·1 m3/s; and a forward speed of 1·69 m/s. This adjustment was eventually compared with the standard sprayer setting, showing that total deposition on the canopy could be increased from 48·4 to 65·6% of the dose applied, without substantially increasing spray losses to the ground.

Foliar deposition and pesticide losses from three air-assisted sprayers in a hedgerow vineyard

Three commercial air-assisted sprayers were tested in a hedgerow vineyard, at full vegetative development (end of July; leaf area index = 1.94), using a water-soluble food dye as a tracer. The spraying equipment used was (1) a high-volume (1355 l ha −1) axial-fan sprayer; (2) a low-volume (246 1 ha −1) compressed-air sprayer (3) a sprayer fitted with deflectable air outlets, allowing an adjustment of the output angle, relative to the row direction, from 90 ° to 118 °. All application techniques appeared to be capable of delivering more than 64% of the sprayed material onto the leaves and grapes. The high-volume sprayer provided the most uniform distribution over the foliage. The change of the output angle from 90 ° to 118 ° did not significantly affect total leaf deposition, but increased the overall variability of the deposits.

Two Water-Soluble Optically Resolvable Dyes for Comparing Pesticide Spray Distribution

A technique for studying pesticide deposit on natural targets using two optically resolvable water-soluble food dyes is described. Flolene FD&;C Blue No.1 and Flolene FD&;C Yellow No.6 can be retrieved from a natural surface (green pepper leaves) and subsequently resolved spectrophotometrically. The ability to resolve two dyes from a single leaf surface eliminates variability due to leaf surface orientation and position within the plant and allows precise comparison of different spray technologies. The system described has a detection limit of ≈ 0.1 ppm. These dyes are safe, water-soluble, and inexpensive tools for research involving comparison and quantification of spray depositions.

A new chromatographic method for the separation of food dye mixtures on thin MgO layers

A new effective TLC method has been developed for the separation of the five main watersoluble food dyes such as indige carmin, cochineal red, acid amaranth I, orange yellow S and tartrazine G. The chromatograms are developed by the ascending technique on thin MgO layers applied onto glass plates, previously activated at 130°C. A 8∶2 mixture of 15% sodium citrate and methanol is used as the developing phase. This composition was selected on the basis of Snyder's theory and the polarity index which for this mixture is 8.3. The proposed method permits the full separation of the dye mixture from a 0.3μl sample solution with concentrations of 1×10−6 mole/liter.

Simultaneous determination of water soluble food dyes by high performance thin layer chromatography

Simultaneous determination of water soluble food dyes by high performance thin layer chromatography

Use of amberlite XAD-2 for isolation and detection ofa water-soluble acid dyes

A method is described in which Amberlite XAD-2 is used as an adsorbent for the isolation of synthetic water-soluble food dyes and for the detection of the dyes by thin-layer chromatography. The acid dyes are adsorbed on the XAD-2 resin in a presence of triethylammonium bicarbonate and then recovered in good yield by elution with emthanol. In XAD-2 thin-layer, chromatography, the solvent system acetone-concentrated ammonia-water (3:1:6 or 6:1:3) gave sharp resolution of the eleven dyes tested, especially of the xanthene compounds.

Separation and identification of water-soluble food dyes by ion-exchange and soap thin-layer chromatography

Eighteen water-soluble food dyes have been studied by chromatography on thin layers of anion-exchange (AG-1-X4, DEAE-cellulose, PAB-cellulose and chitosan and cation-exchange (Dowex 50-X4, Rexyn 102 and humic acid) materials; layers of silanised silica gel impregnated with cationic or anionic detergent were also used. Fourteen of the dyes were separated, but the two orange and the two black dyes were not. Some applications of the techniques to commercial products are reported.

The determination of unsulphonated primary aromatic amines in water-soluble food dyes and other food additives.

EEC directives prescribe limits for the amount of unsulphonated primary aromatic amines present in food colouring matters in general and prohibit the presence of particular carcinogenic amines in food dyes and other food additives. Integrated methods based on solvent extraction and thin-layer chromatography have been devised for identification of these amines, followed by the spectrophotometric determination of their condensation products with 4-dimethylaminocinnamaldehyde. The method is also extended to the determination of primary aromatic amines in biphenyl and to the determination of aminoazobenzenes in the dye Fast Yellow. An additional thin-layer chromatographic method is given for the differentiation between the isomers of naphthylamine as their tosyl derivatives.

The thin-layer chromatographic separation of water-soluble food dyes on silica gel layers

The thin-layer chromatographic separation of water-soluble food dyes on silica gel layers