Soft Drink Samples Research Articles

MONITORING OF BENZOIC ACID LEVELS IN SOFT DRINKS CONSUMED IN ADEN, YEMEN

Benzoic acid is widely used as a food preservative due to its effectiveness in inhibiting the growth of yeast and mold. The undissociated form of benzoic acid is the most potent. In acidic beverages like soft drinks, benzoic acid can react with additives such as ascorbic acid to release benzene, which can pose health concerns. This study aimed to determine the levels of benzoic acid in soft drink samples commonly consumed in Aden, Yemen. Eighteen soft drink samples were analyzed using high-performance liquid chromatography with a UV detector. The highest benzoic acid concentration was found in a FIFA orange sample at 173.87 ppm, while the lowest was 8.40 ppm in a DREAM red sample. Some samples, including MIRINDA orange, FANTA apple, and DILSI red, had no detectable levels of benzoic acid, despite their labels indicating its presence. Overall, the benzoic acid concentrations in all tested samples were within the permissible limits set by local, regional, and international standards.

Determination of Nicotine in Juices, Soft and Energy Drinks collected from Libyan Local Markets Using UV–Visible Spectrophotometer

This study aims to determine the nicotine in juices, soft and energy drinks using a UV-Visible spectrophotometer. In the presented study, sixteen samples (four juices, seven soft drinks, and five energy drinks) are collected from local markets in El-Beida - Libya. A rapid, simple, and reliable extraction method is developed and validated for the determination of nicotine in the samples under study using spectrophotometric methods. The method is validated over a wide linear range of 1.62–81.06 µg/mL with correlation coefficients being consistently greater than 0.9999 by UV-Visible Spectrophotometer. The minimum nicotine level was observed in the juices samples, while the energy drinks samples showed the highest nicotine content. The spectrophotometric measurement indicates that the results of nicotine concentrations in juices samples are in the range of 0.3233 - 0.5238 µg/mL, whereas its concentrations in soft drinks samples are in the range of 0.7251 - 0.9949 µg/mL, and the concentrations in energy drinks samples are in the range of 0.8521 - 1.3471 µg/mL. The criteria considered for validation are linearity, the limit of detection, and the limit of quantitation. The nicotine contents in all the samples analyzed in our study were below the allowable limits set by the US Food and Drugs Administration.

A fast, simple and efficient surface floating organic droplet–based air–assisted liquid–liquid microextraction for simultaneous extraction of multiclass pesticides from environmental water, mineral water and soft drink samples by HPLC–DAD

A fast, simple, efficient and selective surface floating organic droplet–based air–assisted liquid–liquid microextraction method coupled with high performance liquid chromatograph–diode array detector was developed for simultaneous extraction of six multiclass pesticides. The developed method was validated for the extraction, enrichment and quantitative determination of trace level multiclass pesticides from environmental water, mineral water and soft drink samples. The effect of experimental parameters such as type and volume of extraction solvent, addition of salt, solution pH and extraction number were successfully optimized. Under the optimum conditions, the method showed good linearity for all the six multiclass pesticide residues with coefficient of determination within the range of 0.9979–0.9994. The limit of detection and quantification were in the range 0.01 to 0.07 µg L−1 and 0.03 to 0.25 µg L−1, respectively. The reproducibility and repeatability study in terms of %RSD were in the range of 0.88–5.28 and 1.35–6.08, respectively, indicating good precision of the method. The method exhibited acceptable mean relative recovery (%RR) in the range of 71.82 to 110.16 % with %RSDs (n = 3) less than 8 % for all the samples. Thus, the developed method could be utilized as selective extraction and preconcentration of multiclass pesticides from environmental water samples, mineral water and soft drink samples, as well as samples with similar matrices.

A new, fast and selective electrochemical sensor based on Bismuthiol-I for the voltammetric detection of tartrazine, a synthetic food dye, in soft drinks

A new electrochemical sensor (BT-I/GC) was prepared for the determination of tartrazine (TRZ) by modifying the glassy carbon (GC) electrode with 1,3,4-thiadiazoleidine-2,5-dithiol (Bismuthiol I, BT-I). The characterization of the prepared sensor was carried out by some electrochemical techniques and Fourier transform infrared spectroscopy (FT-IR). The rapid and simple determination of TRZ was performed on the surface of the BT-I/GC sensor by differential pulse voltammetry (DPV) technique. Under the optimum experimental conditions, linear working ranges for TRZ detection were found as 38.5 nM-3.72 μM, 3.72 μM-24.10 μM, and 24.10 μM-307 μM, and the value of the limit of detection (LOD) was found as 9.8 nM. The fabricated sensor was used successfully to detect TRZ in soft drink and energy drink samples with recovery values between 95.8 % and 103.8 %.

Soft Drinks as a Dietary Source of Fluoride Exposure

High fluoride exposures can lead to adverse effects such as dental and bone fluorosis, as well as endocrine and cognitive developmental problems. Water is the main dietary source of this ion, although significant concentrations have also been detected in other beverages widely consumed by the population such as soft drinks. A total of 200 soft drink samples (60 flavoured, 70 extracts, 60 fruit juice and 10 soft drinks) were analysed by fluoride ion selective potentiometry. A consumption of 330 mL was estimated for exposure assessment and subsequent F-risk assessment by soft drink consumption. The highest average concentration was found in extract soft drinks (2.45 ± 1.15 mg/L), followed by flavoured (1.71 ± 2.29 mg/L) and carbonated soft drinks (1.38 ± 0.40 mg/L), while the lowest was found in fruit juice soft drinks (1.09 ± 0.62 mg/L). The flavours with the highest concentration were tea-melon and tea-passion fruit with 3.66 ± 0.40 and 3.17 ± 0.56 mg/L respectively and the lowest was lemon flavour with 0.69 mg/L. The contribution of these beverages, considering the UL (Upper level) reference values set by EFSA (European Food Safety Authority) are between 3.28–41.78%, depending on age group and sex.

Electrochemical Study of Sunset Yellow and its Determination in Soft Drink by Differential Pulse Adsorptive Stripping Voltammetry Using Ag-ErGO/GCE

The electrochemical behavior of sunset yellow on the glassy carbon electrode modified with silver and reduced graphene oxide has been investigated by cyclic and differential pulse adsorptive stripping voltammetry. The electrochemical behavior of sunset yellow was reversible and adsorptive on the working electrode. The optimal conditions were obtained as follows: Britton-Robinson (BR) buffer at pH 8.0; adsorption potential 0.4 V; adsorption time 50 s; sweep rate 50 mV/s; linearity range from 10-7 M to 10-6 M; the limits of detection and quantitation were 2.5 × 10­-8 M and 8.3 × 10­-8 M, respectively. The procedure was successfully applied to determine sunset yellow in soft drink samples.

An ultrasensitive electrochemical platform based on copper oxide nanoparticles and poly (crystal violet) for the detection of brilliant blue FCF from soft drinks

In this study, a highly sensitive and quick electrochemical platform based on poly (crystal violet) film and copper oxide nanoparticles for the detection of brilliant blue FCF from various soft beverages was developed. The synthesized copper oxide nanoparticles were investigated with Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. Further, crystal violet was electropolymerized on the surface of the carbon paste electrode modified with copper oxide nanoparticles. The electrochemical properties of poly (crystal) violet/copper oxide nanoparticles modified carbon paste electrode were assessed through the utilization of cyclic voltammetry and electrochemical impedance spectroscopy. Furthermore, the signal towards the oxidation of brilliant blue was examined using the differential pulse voltammetry method. Under ideal experimental conditions, the peak current exhibited a linear relationship with the brilliant blue concentration within the range of 0.01–1.00 nmol/L, with a sensitivity of 294.55 µA nmol/L cm−2 and a significant detection limit of 3 pmol/L. In the presence of other dyes and other food additives, the developed platform showed greater selectivity in detecting brilliant blue. The reliability of the designed platform was demonstrated by the 99.19 – 100.67 recovery percentage for the identification of BB in various soft drink samples.

Ultra small carbon dots from Crocus cancellatus as a highly fluorescence probe for synthetic Ponceau 4R dye sensing in food samples

In this work, for the first time, natural Crocus cancellatus was adopted for the green, low-cost, and simple synthesis of highly fluorescent ultra-small carbon dots (CDs) with well-distributed size using a one-pot hydrothermal treatment. As-synthesized CDs are used as fluorescence sensing probe for quantitative analysis of Ponceau 4R (E124) synthetic food dye, which is widely used. However, excessive consumption of Ponceau 4R poses potential health risks. To obtain better-quality performance of as-synthesized CDs, the time and temperature of the hydrothermal carbonization reaction of crocus were optimized simply. The as-prepared carbon dots exhibit exceptional advantages including excellent fluorescence, satisfactory chemical stability, low toxicity, and excellent biocompatibility. It produced a strong blue fluorescence when irradiated with UV light at 365 nm, which was subsequently effectively employed for Ponceau 4R sensing based on the quenching of fluorescence. The as-prepared CDs was characterized by EDX, XRD, FTIR, SEM, HRTEM, UV–Visible absorption spectrophotometry, and fluorescence. The effects of carbon dots fluorescence emission wavelength, CDs quantity, pH value, and reaction time were investigated to detect Ponceau 4R under optimum conditions. The synthesized carbon dot's fluorescence intensity allowed quantitative determination of Ponceau 4R in the linear range of 60–6000 nM with a detection limit of 40 nM that is lower than all previously published methods. Several soft drink samples were used to validate the potential use of this new fluorescent probe for P4R detection in actual samples with good precision and accuracy.

A Novel Equipment-Free Paper-Based Fluorometric Method for the Analytical Determination of Quinine in Soft Drink Samples.

A simple, equipment-free, direct fluorometric method, employing paper-based analytical devices (PADs) as sensors, for the selective determination of quinine (QN) is described herein. The suggested analytical method exploits the fluorescence emission of QN without any chemical reaction after the appropriate pH adjustment with nitric acid, at room temperature, on the surface of a paper device with the application of a UV lamp at 365 nm. The devices crafted had a low cost and were manufactured with chromatographic paper and wax barriers, and the analytical protocol followed was extremely easy for the analyst and required no laboratory instrumentation. According to the methodology, the user must place the sample on the detection area of the paper and read with a smartphone the fluorescence emitted by the QN molecules. Many chemical parameters were optimized, and a study of interfering ions present in soft drink samples was carried out. Additionally, the chemical stability of these paper devices was considered in various maintenance conditions with good results. The detection limit calculated as 3.3 S/N was 3.6 mg L-1, and the precision of the method was satisfactory, being from 3.1% (intra-day) to 8.8% (inter-day). Soft drink samples were successfully analyzed and compared with a fluorescence method.

Polycyclic aromatic hydrocarbons in high-consumption soft drinks and non-alcoholic beers in Iran: Monitoring, Monte Carlo simulations and human health risk assessment

The present study has focused on measuring the level of 16 PAHs in soft drinks and non-alcoholic beers and their health risk using the MSPE/GC–MS (magnetic solid-phase extraction and gas chromatography-mass spectrometry) method. The average of extraction recoveries (ER) was obtained between 73.048% and 99.879%. The mean concentration of ∑16PAH and ∑8PAHs were 0.702 ± 0.078 ppb and 0.196 ± 0.016 ppb in soft drinks and 1.315 ± 0.199 ppb and 0.288 ± 0.021 ppb in the non-alcoholic beer samples, respectively. The measured BaP for a soft drink (0.00856 ppb) and non-alcoholic beer (0.0197 ppb) were far below the U.S. EPA standard for drinking water quality (0.2 ppb). The TEQBaP of soft drinks (0.039 ppb) was lower than non-alcoholic beer samples (0.061 ppb). The Monte Carlo simulation (MCS) results showed the THQ 95th percentiles of PAHs for soft drink samples in the adult and children were calculated as 9.497E-04 and 2.221E-03, while these amounts for non-alcoholic beer samples in children and adults were 3.341E-03 and 1.430E-03, respectively. The incremental lifetime cancer risk (ILCR) values for adults and children were also 2.841E-07 and 1.328E-06 in soft drinks and 4.273E-07 and 1.996E-06 in non-alcoholic beer samples, respectively. The values of non-carcinogenic and carcinogenic risks of the 16 PAHs in high-consumption soft drinks and non-alcoholic beers in Iran were in the acceptable ranges (hazard quotient < 1 and ILCR 〈10−6).

In Situ Self-Assembled Formation of Nitrogen-Rich Ag@Ti3C2 Film for Sensitive Detection and Spatial Imaging of Pesticides with Laser Desorption/Ionization Mass Spectrometry (LDI-MS)

Pesticide residues are hazardous to human health; thus, developing a rapid and sensitive method for pesticide detection is an urgent need. Herein, novel nitrogen-rich Ag@Ti3C2 (Ag@N-Ti3C2) was synthesized via an ecofriendly, ultraviolet-assisted strategy, followed by in situ formation of a highly homogeneous film on target carriers via a facile water evaporation-induced self-assembly process. Ag@N-Ti3C2 shows greater surface area, electrical conductivity, and thermal conductivity than Ti3C2. This Ag@N-Ti3C2 film overcomes the limitations of conventional matrixes and allows laser desorption/ionization mass spectrometry (LDI-MS) to provide fast and high-throughput analysis of pesticides (e.g., carbendazim, thiamethoxam, propoxur, dimethoate, malathion, and cypermethrin) with ultrahigh sensitivity (detection limits of 0.5-200 ng/L), enhanced reproducibility, extremely low background, and good salt tolerance. Furthermore, the levels of pesticides were quantified with a linear range of 0-4 μg/L (R2 > 0.99). This Ag@N-Ti3C2 film was used for high-throughput analysis of pesticides spiked in traditional Chinese herbs and soft drink samples. Meanwhile, high-resolution Ag@N-Ti3C2 film-assisted LDI-MS imaging (LDI MSI) was used to successfully explore spatial distributions of xenobiotic pesticides and other endogenous small molecules (e.g., amino acids, saccharides, hormones, and saponin) in the roots of plants. This study presents the new Ag@N-Ti3C2 self-assembled film equably deposits on the ITO slides and provides a dual platform for pesticide monitoring and has the advantages of high conductivity, accuracy, simplicity, rapid analysis, minimal sample volume requirement, and an imaging function.

Prevalence of microplastics in commercially sold soft drinks and human risk assessment

Due to the increasing global plastic production and use in recent years, the amount of microplastic (MP) accumulating in the environment has also increased. This microplastic pollution potential has been documented mostly in studies of the sea or seafood. The presence of microplastics in terrestrial foods has therefore attracted less attention, despite the potential for future major environmental risks. Some of these researches are related to bottled water, tap water, honey, table salt, milk, and soft drinks. However, the presence of microplastics in soft drinks has not yet been evaluated in the European continent, including Türkiye. Hence, the current study focused on the presence and distribution of microplastics in ten soft drink brands in Türkiye since the water utilized in the bottling process of soft drinks originates from different water supply sources. Using FTIR stereoscopy and stereomicroscope examination, MPs were detected in all of these brands. According to the microplastic contamination factor (MPCF) classification, 80% of the soft drink samples indicated a high level of contamination with microplastics. The study's findings showed that each liter of consumed soft drinks exposes people to about nine microplastic particles, which is a moderate dose when compared to exposure levels in earlier research. It has been determined that bottle-production processes and the substrates used for food production may be the main sources of these microplastics. The chemical components of these microplastic polymers were polyamide (PA), polyethylene terephthalate (PET) and polyethylene (PE), and fibers were the dominant shape. Compared to adults, children were subjected to higher microplastic loads. The study's preliminary data on MP contamination of soft drinks may be useful for further evaluating the risks exposure to microplastics poses to human health.

Assessment of Microbiological Quality of Different Types of Fruit &amp; Soft Drinks Samples of Dhaka City

Fruit juice is widely consumed everywhere in the world because of its authentic taste and is popular among both adults and children. Several studies have been conducted on common juice available in Dhaka to detect the level of microbial contamination. Consequently, the current study was done to evaluate the microbiology of a total of 25 samples and compare drinks from three different categories (street vending, packaged drinks, and soft drinks) that were collected from various locations throughout the city of Dhaka. Among all the samples fresh juice samples were found to be highly contaminated with different microbes where the total viable bacterial count was within a range of 103 to 106 CFU/ml. However, other pathogenic microbes like E. coli, Pseudomonas spp., Staphylococcus spp., Vibrio spp., and Salmonella spp. also present in fresh juice but were totally absent in other samples. The result indicates that street juice samples may be prepared under unhygienic environments and which may serve as a reservoir of various pathogenic bacteria. The study reveals that government should take necessary action to ensure public health safety. Stamford Journal of Microbiology, Vol.12 (1) 2022: 54-58

Reduced Graphene Oxide and Poly (phenylalanine) Composite Modified Electrode for the Electrochemical Determination of Vanillin

In this study, a simple, low cost and stable electrochemical sensor for vanillin is reported based on glassy carbon electrode (GCE) modified with poly (phenylalanine) and electrochemically reduced graphene oxide (ERGO) composite (poly (phenylalanine)/ERGO/GCE). The surface structure of the bare and modified electrodes was characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The electrochemical behavior of vanillin at phenylalanine)/ERGO/GCE) was also studied by CV. Poly (phenylalanine)/ERGO/GCE) exhibited high electrocatalytic activity for the electrochemical oxidation of vanillin due to the synergetic effects of poly (phenylalanine) and ERGO. From linear sweep voltammetry (LSV) study, the electrode reaction of vanillin is adsorption-controlled process. Furthermore, several electrochemical parameters such as number of electrons transferred (n = 2), number of protons transferred (H+ = 2), electron transfer coefficient (α = 0.66) and surface concentration of vanillin (Ґ = 0.32 nmol cm−2) were calculated. SWV was used for quantitative determination of vanillin at phenylalanine)/ERGO/GCE). Under the optimum conditions, the oxidation peak current of vanillin increased linearly with its concentration in the range 0.25–120 μM with a low detection limit of 0.025 μM. The developed sensor was successfully applied for the determination of vanillin in food and soft drink samples.

Bisphenol A in canned soft drinks, plastic-bottled water, and household water tank from Punjab, India

The aim of this study was the quantification of Bisphenol A (BPA) in canned soft drinks, plastic-bottled water and household water tanks from Punjab, India. Samples of five brands of canned soft drinks and plastic-bottled water purchased from local markets. Fifteen samples each of household plastic water tanks and concrete water tank were selected from three different cities (5 from each city) of Punjab, India. Samples were selected randomly. The plastic household water tank samples were collected in the months of December and June to check the effect of temperature on release of BPA in a plastic water tanks. The analysis method consists of microextraction in packed syringe (MEPS) followed by gas chromatography with mass spectrometric (GC-MS) detection. The detection limits and quantitation for BPA were 0.46 pg/mL and 1.52 pg/mL, respectively. Traces of BPA were detected in all canned soft drinks samples. Canned soft drinks and plastic-bottled water samples of five brands were having the BPA concentrations 8.2-14.01 pg/mL and 60-90 pg/mL, respectively. The BPA concentrations in the plastic water tanks were nondetected-12 pg/mL and nondetected-10 pg/mL in concrete water tank.

Effect of storage on the levels of sodium benzoate in soft drinks sold in some Nigerian market with exposure and health risk assessment.

Soft drinks consumption is still a controversial issue for public health and public policy, as the influence storage condition impacts taste, color and shelf life. In all, fifty (50) soft drinks samples, acquired from Enugu, Aba, Asaba, Onitsha and Owerri markets in Nigeria, were subjected to four different storage conditions namely: room temperature (RT), refrigerated (RF), 40 °C and 60 °C for 15 days after which they were analyzed for sodium benzoate concentration using HPLC - UV/Vis detector. The results showed on the average that at RT and RF, soft drinks from Aba had the highest concentration of sodium benzoate (98.7 mg/L and 112.9 mg/L) respectively while samples from Asaba had least concentration of 39.9 mg/L and 38.1 mg/L. At increased temperature of 40 °C, the concentration of sodium benzoate increased generally across the sample, while at 60 °C, the levels in all the samples analyzed were either reduced to less than 50% or below detection level, which suggest that degradation of sodium benzoate at this elevated temperature could result in benzene formation, which is a known carcinogen. Carcinogenic and non-carcinogenic risk assessment showed that children are at risk compared to adults due to higher sodium benzoate daily intake leading to high rate of hyperactivity in correlation to malaise.

Facile and Selective Determination of Total Phthalic Acid Esters Level in Soft Drinks by Molecular Fluorescence Based on Petroleum Ether Microextraction and Selective Derivation by H2SO4.

Determining the level of phthalic acid esters (PAEs) in packaged carbonated beverages is a current need to ensure food safety. High-selectivity and -accuracy identification of individual PAEs can be achieved by chromatographic and mass spectrometric (MS) techniques. However, these methods are slow; involve complicated, expensive instruments in professional laboratories; and consume a large amount of organic solvents. As such, a food analysis method is needed to conveniently and rapidly evaluate multiple contaminants on site. In this study, with the assistance of ultrasound, we quickly determined the total PAEs in soft drinks using 1.5 mL of petroleum ether in one step. Then, we determined the characteristic molecular fluorescence spectrum of all PAEs in samples (excitation (Ex)/emission (Em) at 218/351 nm) using selectively concentrated sulfuric acid derivatization. The relative standard deviations of the fluorescent intensities of mixed solutions with five different PAEs were lower than 7.1% at three concentration levels. The limit of detection of the proposed method is 0.10 μmol L−1, which matches that of some of the chromatographic methods, but the proposed method uses less organic solvent and cheaper instruments. These microextraction devices and the fluorescence spectrometer are portable and provide an instant result, which shows promise for the evaluation of the total level of PAEs in beverages on site. The proposed method successfully detected the total level of PAEs in 38 kinds of soft drink samples from local supermarkets, indicating its potential for applications in the packaged beverage industry.

Sodium benzoate in locally available soft drinks and its effect on DNA damage and liver function in rats

Sodium benzoate (E211) is used as a preservative in several kinds of food. One of the essential uses of E211 is to preserve non-alcoholic carbonated beverages. The amount of sodium benzoate in 17 local soft drink samples was estimated in the present study. The in vivo effects on biochemical aspects of the liver, kidney function, and DNA damage in lymphocytes were also investigated after oral administration of sodium benzoate in rats over 12 days. The control and experimental groups were fed standard pellet diet and distilled water ad libitum; and administered distilled water (control) and different concentrations (30, 60, and 120 mg/kg body weight) of sodium benzoate once daily through a stomach tube (0.5 ml), respectively. The alkaline comet assay was performed to investigate the possible DNA damage induced by E211 in lymphocytes. At the end of the experiment, after overnight fasting the rats were sacrificed and blood samples were collected. Animals showed no significant weight loss or gain. The investigation revealed that twelve samples contained a higher level, and the rest had trace or below the recommended maximum permitted concentration (150 mg/l) of E211 as a preservative in the soft drinks. The percentage of tail DNA (p &lt; 0.01) and olive tail movement (p &lt; 0.05) was significantly increased in lymphocytes that were treated with high concentration (120 mg/kg body weight) of sodium benzoate, indicated substantially higher DNA damage (3.5 times) in lymphocytes compared to control. Moreover, serum AST activity level was increased significantly (p&lt;0.05) in the group treated with a higher dose (120 mg/kg body weight) of E211, indicating malfunction of the liver. The preservative did not significantly affect serum ALT and ALP activity, total bilirubin, creatinine, and urea level. Nonetheless, our findings suggest that caution should be adopted for using sodium benzoate as a preservative in various food products. Dhaka Univ. J. Biol. Sci. 30(3 CSI): 371-383, 2022 (June)

Identification and quantification of sodium benzoate in soft drinks available in Tangail region by high-performance liquid chromatography

Sodium benzoate is a permitted food additive by international laws in processing restrictive amounts, but its content must be declared and must not exceed the established limits by legislation. An experimental study was performed by high-performance liquid chromatography (HPLC) for determining the level of sodium benzoate in different brands of soft drinks available in the markets, stores, and shops in the Tangail region of Bangladesh. A Luna 5 µ C18 (2) 100A column (250×4.6 mm) was used for the chromatographic analysis. Chromatographic separation was achieved with an isocratic solvent system comprising sodium acetate and acetic acid buffer (pH = 4.0)/acetonitrile in the ratio of 80:20 (1 mL/min) at 37oC and the chromatograms were recorded at 254 nm. The limit of detection and quantification for sodium benzoate was 0.0000493 mg/100 mL and 0.000149 mg/100 mL, respectively. Quantification of the selected brand soft drinks revealed that the level of the used sodium benzoate was within the FDA standard range. However, by comparing with the Bangladesh Standard and Testing Institute (BSTI), brand -2 and brand-3 soft drink samples were found to exceed the current legal limits.

Application of Response Surface Methodology to Optimize Solid-Phase Extraction of Benzoic Acid and Sorbic Acid from Food Drinks.

An experimental design was applied for the optimization of the extraction process of two preservatives, benzoic and sorbic acids (BA, SA), from food drinks. A simple, rapid, and reliable solid-phase extraction (SPE) method for the simultaneous extraction of these two preservatives and their determination by liquid chromatography with a diode array detector was considered. Box–Behnken design (BBD) was applied to both steps of the SPE process: (i) the sample percolation to ensure the retention of the totality of the acids by the silica-based C18 sorbent; (ii) the elution step to ensure desorption of the totality of the acids from the cartridge. Thus, the volume, pH, and flow rate of the sample, and the percentage of MeOH, volume, and flow rate of the elution solvent, were optimized. Sample volume and pH have a significant influence (p < 0.0001 and p = 0.0115) on the percolation yield. However, no effect was recorded for the flow rate (p > 0.05). Flow rate also has no significant effect on the elution efficiency. The proposed new solid-phase extraction method, which can be easily applied to routine monitoring of preservatives BA and SA in juice and soft drink samples, included 0.5 g of C18 sorbent, 1 mL of food drink adjusted to pH 1 and percolated at 4.5 mL min−1, and 1 mL of a solvent mixture composed of methanol/acidified water (pH = 2.6) (90:10, v/v) used in the elution step at a flow rate of 4.5 mL min−1. Validation of the SPE method and the technique of analysis were evaluated, namely, the accuracy, precision, detection, and quantification limits and linearity. Recovery percentages of benzoic and sorbic acids were above 95% with relative standard deviations lower than 1.78%. Detection and quantification limits were 0.177 and 0.592 µg mL−1, and 0.502 and 0.873 µg mL−1 for benzoic acid and sorbic acid respectively. Optimal conditions were applied to commercial fruit juices and soft drinks and a minimal matrix effect was observed. This method was compared with other SPE methods using oxidized activated carbon and multiwalled carbon nanotubes as adsorbents. The yields determined with these last two were low compared to those determined with our method.