Determination of Trace Amounts of Cd(II), Cu(II), and Ni(II) in Food Samples Using a Novel Functionalized Magnetic Nanosorbent

This work describes a novel sorbent based on functionalization of magnetic nanoparticles by 2-aminobenzothiazole and its application in the extraction and preconcentration of trace amount of Cd(II), Cu(II), and Ni(II) ions. This nanosorbent was characterized by Fourier transfer infrared spectroscopy, thermal analysis, X-ray powder diffraction, elemental analysis, and scanning electron microscopy. The effects of various factors such as pH value, sorption time, sorbent dosage, type, volume, and concentration of the eluent as well as the elution time were investigated. Following the sorption and the elution of target analytes, the Cd(II), Cu(II), and Ni(II) ions were determined by flame atomic absorption spectrometry. Under the optimal conditions, the limits of detection (LODs) were 0.03, 0.009, and 0.1 μg L^?1 for Cd(II), Cu(II), and Ni(II), respectively. Linearity was within the range of 0.1–75 ng mL^?1 for Cd(II), 0.03–50 ng mL^?1 for Cu(II), and 0.5–100 ng mL^?1 for Ni(II) in the initial solution with r ² values greater than 0.9978. The relative standard deviations of the method were less than 8.4 %. The preconcentration factor of the method was 277. The sorption capacity of this new sorbent was 65, 78, and 49 mg g^?1 for Cd(II), Cu(II), and Ni(II), respectively. The proposed method was validated using two certified reference materials (LGC 6010 hard drinking water and NIST SRM 1515 apple leaves) in order to exhibit its applicability. Ultimately, this method was applied to the rapid extraction of the trace quantities of Cd(II), Cu(II), and Ni(II) ions in different food samples, and satisfactory results were obtained.     

A novel 4-(2-pyridylazo) resorcinol functionalised magnetic nanosorbent for selective extraction of Cu(II) and Pb(II) ions from food and water samples

This paper describes a novel sorbent based on 4-(2-pyridylazo) resorcinol functionalised magnetic nanoparticles and its application for the extraction and pre-concentration of trace amounts of Cu(II) and Pb(II) ions. The nanosorbent was characterised by Fourier transform infrared spectroscopy, X-ray powder diffraction, thermal analysis, elemental analysis and scanning electron microscopy. The effects of various parameters such as pH, sorption time, sorbent dosage, elution time, volume and concentration of eluent were investigated. Following the sorption and elution of analytes, Cu(II) and Pb(II) ions were quantified by flame atomic absorption spectrometry. The limits of detection were 0.07 and 0.7 μg l^?1 for Cu(II) and Pb(II), respectively. The relative standard deviations of the method were less than 7%. The sorption capacity of this new sorbent were 92 and 78 mg g^?1 for Cu(II) and Pb(II), respectively. Finally this nanosorbent was applied to the rapid extraction of trace quantities of Cu(II) and Pb(II) ions in different real samples and satisfactory results were obtained.     

Determination of heavy metal ions in vegetable samples using a magnetic metal–organic framework nanocomposite sorbent

This paper describes the synthesis and application of a novel magnetic metal–organic framework (MOF) [(Fe₃O₄-benzoyl isothiocyanate)/Cu₃(benzene-1,3,5-tricarboxylate)₂] to pre-concentrate trace amounts of Cd(II), Pb(II), Zn(II) and Cr(III) ions and their determination by flame atomic absorption spectrometry. A Box–Behnken design was used to find the parameters affecting the pre-concentration procedure through response surface methodology. Three factors including uptake time, amount of the magnetic sorbent and pH of the sample were selected as affecting factors in the sorption step, and four factors including type, volume and concentration of the eluent as well as the elution time were selected in the elution step for the optimisation study. The opted values were 30 mg, 10.1 min, 5.9, EDTA, 4.0 ml, 0.57 mol l^–1 EDTA solution and 13.0 min for the amount of the magnetic sorbent, uptake time, pH of the sample, type, volume, concentration of the eluent, and elution time, respectively. The limits of detection (LODs) were 0.12, 0.7, 0.16, and 0.4 ng ml^?1 for Cd(II), Pb(II), Zn(II) and Cr(III) ions, respectively. The relative standard deviations (RSDs) of the method were less than 7.2% for five separate batch experiments for the determination of 30 μg l^?1 of Cd(II), Pb(II), Zn(II) and Cr(III) ions. The sorption capacity of the [(Fe₃O₄-benzoyl isothiocyanate)/MOF] was 175 mg g^?1 for Cd(II), 168 mg g^?1 for Pb(II), 210 mg g^?1 for Zn(II) and 196 mg g^?1 for Cr(III). It was found that the magnetic MOF nanocomposite demonstrated a higher capacity compared with Fe₃O₄-benzoyl isothiocyanate. Finally, the magnetic MOF nanocomposite was successfully applied to the rapid extraction of trace amounts of the heavy metal ions from vegetable samples.     

Synthesis,characterisation and analytical application of Fe3O4@SiO2@polyaminoquinoline magnetic nanocomposite for the extraction and pre-concentration of Cd(II) and Pb(II) in food samples

This work describes a novel Fe₃O₄@SiO₂@polyaminoquinoline magnetic nanocomposite and its application in the pre-concentration of Cd(II) and Pb(II) ions. The parameters affecting the pre-concentration procedure were optimised by a Box–Behnken design through response surface methodology. Three variables (extraction time, magnetic sorbent amount and pH) were selected as the main factors affecting the sorption step, while four variables (type, volume and concentration of the eluent, and elution time) were selected as main factors in the optimisation study of the elution step. Following the sorption and elution of analytes, the ions were quantified by flame atomic absorption spectrometry (FASS). The limits of detection were 0.1 and 0.7 ng ml^?1 for Cd(II) and Pb(II) ions, respectively. All the relative standard deviations were less than 7.6%. The sorption capacities of this new sorbent were 57 mg g^?1 for Cd(II) and 73 mg g^?1 for Pb(II). Ultimately, this nanocomposite was successfully applied to the rapid extraction of trace quantities of these heavy metal ions from seafood and agricultural samples and satisfactory results were obtained.     

Separation‐preconcentration of Cu,Cd, Pb and Ni in various water and food samples on Sepabeads SP‐207

This study presents a solid phase extraction (SPE) procedure for preconcentration and separation of Cu(II), Cd(II), Pb(II) and Ni(II), as their diethyldithiocarbamate chelates on Sepabeads SP‐207 resin using flame atomic absorption spectrometry. The parameters, including pH, sample volume, eluent type and volume etc., were optimised. The influences of the some alkali, alkali earth and transition metal ions on the involvement of copper(II), cadmium(II), lead(II) and nickel(II) were also examined. The preconcentration factor was calculated as 50. The limit of detections of the analyte ions (k = 3, N = 21) were 0.18 μg L^?1 (Cu), 0.17 μg L^?1 (Cd), 0.55 μg L^?1 (Pb) and 1.67 μg L^?1 (Ni). GBW 07605 Tea and NRCC‐DORM‐2 Dogfish Muscle certificated reference materials were used for confirm of method. The method was successfully performed for determination of Cu(II), Cd(II), Pb(II) and Ni(II) ions in water and food samples. The relative standard deviation was found to be lower than 7%.     

Multi-element determination in some foods and beverages using silica gel modified with 1-phenylthiosemicarbazide

ABSTRACT

1-Phenylthiosemicarbazide bonded modified silica gel (PTC-SG) was synthesised and characterised by FTIR, SEM and elemental analysis for a novel separation/preconcentration of multiple elements based on solid phase extraction. The analytical parameters including pH of solutions, amounts of PTC-SG, flow rates of sample, eluent type and sample volume were optimised. The adsorption capacities of PTC-SG were found to be 7.9, 6.4, 6.3, 8.3, 7.2, 8.9 and 6.6 mg/g for Cu(II), Cd(II), Pb(II), Co(II), Cr(III), Ni(II) and Mn(II), respectively. The limit of detection (LOD) was calculated as 3x the standard deviation(s) of the reagent blank (k = 3, N = 21) and the LOD values were obtained to be 0.98 µg L^?1 (Cu), 0.65 µg L^?1 (Cd), 0.57 µg L^?1 (Pb), 1.12 µg L^?1 (Co), 1.82 µL^?1 (Cr), 1.67 µg L^?1 (Ni) and 0.55 µg L^?1 (Mn). Certified reference materials were used to test the validation of the present method. The new solid phase extraction method was successfully applied to determination of the amount of multiple elements in food and beverage samples.     

Graphene-Based Preconcentration System Prior to Energy Dispersive X-Ray Fluorescence Spectrometric Determination of Co,Ni, and Cu Ions in Wine Samples

A combination of dispersive micro solid-phase extraction (DMSPE), based on graphene as a solid sorbent, with energy dispersive X-ray fluorescence spectrometry (EDXRF) is proposed for preconcentration and determination of Co(II), Ni(II), and Cu(II) ions in wine samples. In the developed procedure, cupferron complexes of metal ions are adsorbed on graphene dispersed in aqueous samples. After the adsorption process, aqueous samples are passed through a membrane filter with the use of filtration assembly, and then loaded filters are directly measured using EDXRF. In order to obtain high recovery of the metal ions, various analytical parameters influencing sorption were optimized, such as pH, amount of graphene, Triton X-100 and cupferron, sample volume, and sorption time. Under optimal conditions, the calibration plots cover the 2 to 100 ng mL^?1 range for Co(II) and Ni(II), and 2 to 150 ng mL^?1 for Cu(II). The detection limits of 0.08, 0.08, and 0.07 ng mL^?1 for Co(II), Ni(II), and Cu(II) were obtained using 50 mL sample volume and 200 μg of graphene. The precision (at a 20 ng mL^?1 level for n?=?10) is lower than 3.5 %. The proposed method was successfully applied to determination of Co, Ni, and Cu in wine samples.     

The physicochemical characterization,equilibrium, and kinetics of heavy metal ions adsorption from aqueous solution by arrowhead plant (Sagittaria trifolia L.) stalk

The arrowhead plant stalk (APS) has been investigated as a novel biosorbent for removal of Cd(II), Pb(II), and Cr(III) ions from aqueous solution. The surface physicochemical properties favorable for metals adsorption were systematically characterized. The Langmuir isotherm fitted well with Cd(II) and Pb(II) adsorption process onto APS while Dubinin–Radushkevich model best described Cr(III) sorption. The maximal adsorption capacities of APS for Cd(II), Pb(II), and Cr(III) were up to 38.2, 97.1, and 23.5 mg·g^?1, respectively. The adsorption kinetic data of individual metal fitted the pseudo‐second order model best. The adsorption of Cd(II) was exothermic, whereas the Pb(II) and Cr(III) underwent endothermic reaction. Overall, this investigation indicated, for the first time, APS is a potentially efficient biosorbent applied in Cd(II), Pb(II), and Cr(III) adsorption. It is also helpful for further utilizing the abundant quantity of APS which were abandoned in dietary arrowhead processing.

Practical applications

The growing food industry around world generates large quantity of by‐products. The high value‐added utilization of food processing by‐products is one of the most important area in food industry. An attempt was made in present study to use the food by‐product, arrowhead plant stalk (APS), as a novel biosorbent for removing Cd(II), Pb(II), and Cr(III) ions. In present study, it was evidenced that the adsorption capacities of APS for Cd(II), Pb(II), and Cr(III) were obviously higher than those of most reported agricultural by‐products. This finding is significant for sustainable utilization of food crop arrowhead plant and elimination of environmental issues arising from the abandoned arrowhead plant stalk.     

Method for the determination of cadmium,lead, nickel,cobalt and copper in seafood after dispersive liquid–liquid micro-extraction

A method using dispersive liquid–liquid micro-extraction (DLLME) and detection by inductively coupled plasma optical emission spectroscopy (ICP-OES) was developed for the determination of trace elements in seafood samples. The procedure allowed the simultaneous determination of Cd(II), Pb(II), Ni(II) Cu(II) and Co(II) after pre-concentration using sodium diethyldithiocarbamate (DDTC) as a chelating agent. Under optimised conditions, the method had a limit of detection (LOD) of 0.03, 0.11, 0.12, 0.18 and 0.12 µg l^?1 for Cd(II), Pb(II), Ni(II) Cu(II) and Co(II), respectively. The following enrichment factors were obtained: 16 (Cd), 34 (Pb), 20 (Ni) 34 (Cu) and 12 (Co). The procedure was applied for the determination of these elements in seafood (shrimp, mussel, bass and mullet) samples. The method is simple, efficient and easy to perform for the simultaneous determination of elements in seafood samples by ICP-OES.     

Heavy metals in vegetables sold in the local market in Jordan

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009–0.275 mg kg^?1 wet weight, 0.004–0.060 mg kg^?1, 0.003–0.401 mg kg^?1, 0.105–3.51 mg kg^?1, 0.15–1.15 mg kg^?1, 0.93–14.39 mg kg^?1, 0.044–0.702 mg kg^?1, 0.072–0.289 mg kg^?1 and 2.23–6.65 mg kg^?1, respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.     

Toxic and micronutrient elements in organic,brown and polished rice in Brazil

Concentration levels of As, Cd, Hg, Pb, Tl, Sn, Sb Co, Cu, Mn, Se, Zn, Cr, Ni and Mo in different types of rice cultivated in irrigated fields in Brazil were evaluated. Arsenic, Cd, Pb, Zn, Mn and Cu were found in higher concentrations in brown rice samples, suggesting the prevalence of these elements in the bran. Meanwhile, lower concentrations of Pb, Mo, Cr, Se and Co were found in parboiled rice. Organic rice did not differ of cultivated conventionally rice. Thallium, Hg and Sb were not detected in any rice sample whose limits of detection were 0.7 μg kg^?1, 2.5 μg kg^?1 and 8 μg kg^?1, respectively. The concentrations of the investigated elements were compared with those reported for polished rice and brown rice from other countries, unveiling concentrations in general at the same level for rice produced at non-contaminated sites.     

Determination of Cd (II), Cu (II), and Pb (II) in Some Foods by FAAS after Preconcentration on Modified Silica Gels with Thiourea

Abstract: This study describes preconcentration method for determination of Cd (II), Cu (II), and Pb (II) in some food samples. Silica gel was modified with thiourea and characterized by IR and C, H, N, S elemental analysis. Modified silica gel was used as a solid phase extraction for determination of Cd (II), Cu (II) and Pb (II) in tuna fish, biscuit, black tea, rice, ka?ar cheese, honey, tomato paste, and margarine samples. The analytical conditions including eluent type, pH of sample solutions, flow rates of sample and eluent solutions, etc. were optimized. The influence of the matrix ions on the involvement of the Cd (II), Cu (II), and Pb (II) were also studied. GBW 07605 tea standard reference material was used for validation of method. The method was successfully applied for the determination of Cd (II), Cu (II), and Pb (II) ions in food samples. The detection limits were in the range of 0.81 μg/L, 0.38 μg/L, and 0.57 μg/L for cadmium, copper and lead, respectively. The relative standard deviations of the procedure were below 10%. The sorption capacities were found as 92 μmol/L Cd (II), 286 μmol/L Cu (II), and 121 μmol/L Pb (II).     

<Emphasis Type="SmallCaps">l</Emphasis>-Cysteine Functionalized Silica Gel as an Efficient Adsorbent for the Determination of Heavy Metals in Foods by ICP-MS

A novel l-cysteine functionalized silica gel adsorbent (SG-Cys) was successfully synthesized and characterized by Fourier transform infrared (FTIR) spectra and elemental analysis. An efficient method for simultaneous determination of heavy metals [V (V), Cr (VI), Cu (II), As (V), Cd (II), and Pb (II)] was developed by inductively coupled plasma-mass spectrometry (ICP-MS) coupled with pre-concentration with the prepared SG-Cys adsorbent. The experimental parameters, including the solution pH, sample flow rate, eluent volume, eluent type, and concentration, have been systematically optimized to obtain higher enrichment factors of target ions. Under the optimum conditions, the enrichment factors of V (V), Cr (VI), Cu (II), As (V), Cd (II), and Pb (II) reached 123, 100, 86, 106, 97, and 94, respectively, and the detection limits were as low as 1.8–3.7 ng L^?1. The proposed method has been applied to the determination of trace heavy metals in water, rice, wheat, corn, and tea samples, which exhibited a satisfactory recovery in the range of 90.6–106.0 %.     

Determination of toxic and essential elements in sunflower honey from Thrace Region,Turkey

The aim of this study was to determine the levels of copper (Cu), manganese (Mn), zinc (Zn), iron (Fe), cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni) and selenium (Se) in sunflower honeys obtained from Thrace Region of Turkey. Trace and toxic element determination was performed by atomic absorption spectrometry after microwave digestion. The accuracy of the method was checked by the standard reference material, NIST‐SRM 1515 Apple leaves. The maximum contents of trace and toxic elements in honey samples from Kesan (polluted area) were found as 0.46, 0.82, 1.98, 14.0, 9.86 μg kg^?1, 0.48 mg kg^?1, 137, 115 and 290 μg kg^?1 for Cu, Mn, Zn, Fe, Cd, Pb, Cr, Ni and Se, respectively.     

Metal levels in Trachurus trachurus and Cyprinus carpio in Turkey

Concentrations of five toxic metals were determined in two fish species from Turkish cities during 2010–2011. The obtained lead concentrations for all of the studied Trachurus trachurus (mean 777 μg kg^?1) and Cyprinus carpio (mean 439 μg kg^?1) samples were found to be higher than the maximum level (ML) of 300 μg kg^?1, while Cd concentrations in the same samples were lower than the ML. Mean chromium (501 μg kg^?1), Ni (272 μg kg^?1) and Cu (785 μg kg^?1) concentrations in T. trachurus were significantly higher than in C. carpio (336 μg Cr kg^?1, 229 μg Ni kg^?1 and 394 μg Cu kg^?1), similar to those of Pb and Cd. Measured Pb concentrations in T. trachurus tissues are significantly higher than the ML, while those of Cd in both T. trachurus and C. carpio species were lower than the ML values.     

Solid‐phase extraction of lead and copper on a polyhydroxybutyrate‐b‐polydimethyl siloxane (PHB‐b‐PDMS) block copolymer disc and flame atomic absorption spectrometric determination of them in water and food samples

A separation and preconcentration procedure based on solid‐phase extraction of Cu(II) and Pb(II) as their Sudan III chelates on polyhydroxybutyrate‐b‐polydimethyl siloxane (PHB‐b‐PDMS) block copolymer disc has been established. Various analytical parameters including pH, amount of Sudan III, eluent type and volume, sample volume, flow rates were optimised. The effects of concomitant ions on the retentions of the analyte ions on PHB‐b‐PDMS disc were also examined. The detection limits for Cu(II) and Pb(II) were found to be 2.3 and 4.9 μgL^?1, respectively. Preconcentration factor was found to be sixty. Relative standard deviation was found to be 5%. The accuracy of the method was confirmed by analysing certified reference materials (TMDA 54.4 fortified lake water and NIST 1515 Apple leaves). Optimised method was applied to determine the analyte ions in various water and food samples from Turkey.     

Determination of Pb(II) Ions Using Novel Ion-Imprinted Polymer Magnetic Nanoparticles: Investigation of the Relation Between Pb(II) Ions in Cow’s Milk and Their Nutrition

The application of novel Pb(II) ion-imprinted polymer coated on magnetic mesoporous silica was investigated in preconcentration and determination of low level of Pb(II) ions. The job proposed a new method for preconcentration and determination of Pb(II) ions. This novel sorbent was characterized by scanning electron microscopy, thermal gravimetric/differential thermal analysis, elemental analysis, and low-angle X-ray powder diffraction. Effects of various factors such as the effects of the pH of sample solution, eluent (include type, concentration and volume), adsorption and desorption time which are effective in method efficiency, were appraised through this study. In order to investigate the selectivity of this sorbent toward Pb(II) ion, the effects of variety of foreign ions interfering on preconcentration and recovery of Pb(II) ions were also investigated. The limit of detection (LOD) was found to be 0.7 μg L^?1 and the recovery and relative standard deviation of the method were 96.6–102.4 % and 1.3–3.3 %, respectively. Validation of the outlined method was performed by analyzing several standard reference materials with certified Pb(II) concentrations. Finally, this sorbent was applied for separation and determination of Pb(II) ion in grass and cow’s milk, which showed their lead concentration to be below the detection limit of flame atomic adsorption spectroscopy.     

Monitoring of Zn(II), Cd(II), Pb(II) and Cu(II) During Refining of Some Vegetable Oils Using Differential Pulse Anodic Stripping Voltammetry

In this study, a novel approach has been developed using differential pulse anodic stripping voltammetry (DPASV) for the simultaneous determination of Zn(II), Cd(II), Pb(II) and Cu(II) in edible oils at hanging mercury drop electrode. The microwave digestion of oil samples was carried out with concentrated HNO₃ and H₂O₂. KNO₃ was used as a supporting electrolyte. The experimental conditions optimized such as deposition time, stirring rate and size of mercury drop were 300 s, 600 rpm and 10 mm², respectively. The method was applied to quantify Zn(II), Cd(II), Pb(II) and Cu(II) in crude and refined hazelnut, corn, sunflower and olive oils. During refining of different vegetable oils, the removal efficiencies of Zn(II), Cd(II), Pb(II) and Cu(II) were calculated as 98.20–99.91, 98.50–99.90, 95.26–99.76 and 95.93–99.92 %, respectively. The limits of detection for Zn(II), Cd(II), Pb(II) and Cu(II) were 2.1?×?10^?8, 8.7?×?10^?10, 7.1?×?10^?9 and 3.4?×?10^?9 and the limits of quantification were 6.8?×?10^?8, 2.9?×?10^?9, 2.3?×?10^?8 and 1.1?×?10^?8 M with linear regression coefficients (R ²) of 0.9930, 0.9928, 0.9893 and 0.9931, respectively. It was observed that the above metals in crude and refined vegetable oils could be determined simultaneously by the DPASV method.     

Solid Phase Extraction of Pb(II) and Cd(II) in Food,Soil, and Water Samples Based on 1-(2-Pyridylazo)-2-Naphthol-Functionalized Organic–Inorganic Mesoporous Material with the aid of Experimental Design Methodology

An effective sorbent of 1-(2-Pyridylazo)-2-naphthol-functionalized mesoporous silica has been prepared to simultaneous separation and preconcentration of lead and cadmium ions in aqueous solution. Structural characterization of 1-(2-Pyridylazo)-2-naphthol-functionalized organic–inorganic hybrid mesoporous materials was conducted by Fourier transform infrared spectroscopy, transmission electron microscopy, N₂ adsorption–desorption measurement, X-ray diffraction, and elemental and thermal analysis, which confirmed the successful grafting of organic moiety on mesoporous silica. The affecting parameters on adsorption and desorption steps were optimized by Box-Behnken design through response surface methodology. Three variables (pH value, sorption time, and amount of the sorbent) were selected as the main factors affecting sorption step, while four variables (type of eluent, eluent volume, eluent concentration, and elution time) were selected for desorption step in the optimization study. The optimized values by this optimization method were 10 mg, 8 min, 6.3, HCl, 1.6 mL, 1.2 mol L^?l HCl, and 10 min, for amount of sorbent, sorption time, pH of solution, type, volume, and concentration of the eluent, and elution time, respectively. Under the optimized conditions, the detection limits of the proposed method for lead and cadmium ions were found to be 0.9 and 0.04 μg L^?1, respectively, while the relative standard deviation (RSD) for five replicate measurements was calculated to be <3 % for both ions. For proving that the proposed method is reliable, a wide range of food, soil, and water samples with different and complex matrixes was used.     

Aluminium,nickel, cadmium and lead in candy products and assessment of daily intake by children in Spain

Aluminium (Al), nickel (Ni), cadmium (Cd) and lead (Pb) levels in a total of 263 samples of 12 types of candies widely consumed in Spain, were evaluated. Samples were analysed using an ICP-MS method after acidic sample mineralization. Concentration ranges of Al, Ni, Cd and Pb were 21.28–62.91 µg g^?1, 0.40–1.27 µg g^?1, 0.12–1.01 µg g^?1 and 1.03–7.14 µg g^?1, respectifgvely. Statistically significant positive correlations were calculated between concentrations of Ni–Al and Pb–Cd (p-values < 0.05). Taking into consideration the relatively high metal content, together with the high caloric density of these products, as well as high content of particular nutrients such as sugars that can induce development of certain pathologies like obesity and caries, indicate that frequent consumption of candy products is not recommended.