Occurrence of patulin and its dietary intake through apple juice consumption by the Spanish population

A survey was conducted to determine levels and dietary intake of Patulin (PAT) from apple juices consumed in Spain. One hundred samples of apple juice were bought from distinct supermarkets. PAT was extracted by a liquid–liquid extraction technique and analysed with a micellar electrokinetic chromatography (MEKC) method. 66% of the samples contained PAT over the limit of detection of the method (0.7 μg L⁻¹). The PAT apple juice mean and median levels obtained were 19.4 and 4.8 μg L⁻¹, respectively, in a range between 0.7 and 118.7 μg L⁻¹. In 11% of the samples, PAT contamination exceeded the maximum permitted level of 50 μg L⁻¹ established by the EU regulation. In Spain, no significant variations were observed with respect to data published 15 years ago.     

Determination of aflatoxins in eggs,milk, meat and meat products using HPLC fluorescent and UV detectors

Raw and pasteurised sheep’s, cow’s and goat’s milk, eggs, and beef samples from different local markets in Jordan were collected during a period of 5 months (January through May 2007) and examined for aflatoxins B1(AFB1), B2(AFB2), G1(AFG1), G2(AFG2), M1(AFM1) and M2(AFM2). The samples were analysed with high performance liquid chromatography (HPLC) using UV and Fluorescent detectors. The analysed samples of milk collected in January were found to contain 0.56 μg L⁻¹ AFM1 and 0.1 μg L⁻¹ AFM2 whilst, the concentration of AFM1 and AFM2 was < 0.05 μg L⁻¹ for milk samples collected between March and May. The AFB1, AFB2, AFG1 and AFG2 contents in the analysed food products ranged from 1.10 to 8.32 μg L⁻¹ and 0.15 to 6.36 μg L⁻¹ in imported and fresh meat samples collected during March, respectively. The mean recovery for the HPLC method was 92% to 109% and the quantification levels were 50 ng L⁻¹ for AFM1 and AFM2. The AFM1 was found in 10% of the tested samples with concentrations between 0.08 and 1.1 μg kg⁻¹ and AFM2 was only found in 1.82% of the tested samples with a level of 0.1 μg kg⁻¹. The AFM1 levels in the examined foods were higher than the maximum level of AFM1 in liquid milk set by the European Community and Codex Alimentarius of 50 ng L⁻¹.     

Trace element levels in honeys from different regions of Turkey

A survey of 25 honey samples from different botanical origin, collected all over the Turkey was conducted to assess their trace element contents. The aim of this study was to determine the levels of cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr), zinc (Zn), aluminium (Al) and selenium (Se) in honey samples from different regions of Turkey. Trace element contents were determined by a flame and graphite furnace atomic absorption spectrometry technique after dry-ashing, microwave digestion and wet-digestion. The accuracy of the method was corrected by the standard reference material, NIST-SRM 1515 Apple leaves. The contents of trace elements in honey samples were in the range of 0.23–2.41 μg g⁻¹, 0.32–4.56 μg g⁻¹, 1.1–12.7 μg g⁻¹, 1.8–10.2 μg g⁻¹, 8.4–105.8 μg kg⁻¹, 2.6–29.9 μg kg⁻¹, 2.4–37.9 μg kg⁻¹, 0.9–17.9 μg kg⁻¹, 83–325 μg kg⁻¹ and 38–113 μg kg⁻¹ for Cu, Mn, Zn, Fe, Pb, Ni, Cr, Cd, Al and Se, respectively. Iron was the most abundant element while cadmium was the lowest element in the Turkish honeys surveyed. The results showed that trace element concentrations in the honeys from different regions were generally correlated with the degree of trace element contamination of the environment.     

Multiresidue method for analysis of pesticides in pepper and tomato by gas chromatography with nitrogen–phosphorus detection

An analytical multiresidue method for the simultaneous determination of various classes of pesticides in vegetables (pepper and tomato) was developed. Vegetable samples are extracted with acetone and the pesticides are partitioned into ethyl acetate/cyclohexane. Final determination was made by gas chromatography with nitrogen–phosphorus detection. Confirmation analysis of pesticides was carried out by gas chromatography coupled with mass spectrometry in the selected ion monitoring (SIM) mode. The identification of compounds was based on retention time and on comparison of the primary and secondary ions. Recovery studies were performed at 0.05, 0.1 and 0.02 mg kg⁻¹ fortification levels of each compound and the recoveries obtained ranged from 70.1% to 128.5% with relative standard deviations lower than 7%. The method showed good linearity over the range assayed 50–1500 μg l⁻¹ and the detection and quantification limits for the pesticides studied varied from 0.1 to 4.4 μg kg⁻¹ and 0.4 to 14.5 μg kg⁻¹, respectively. The proposed method was used to determine pesticides levels in peppers and tomatoes grown in experimental greenhouses.     

Effects of skin and grilling method on formation of heterocyclic amines in chicken pectoralis superficialis muscle

Mutagenic heterocyclic amines (HAs) originate in processed proteinaceous foods. The effects of the presence of skin (with vs. without) and of grilling method (two plate vs. infrared) on the content of HAs in grilled chicken pectoralis superficialis muscle (temperature, 220 °C) were investigated. HA precursors (creatine, creatinine, free amino acids and carbohydrates) and HAs of these raw and grilled breast muscles were determined. The muscles originated from 24 birds of either sex (provenance Ross; aged 40-45 days). The HA content was determined in homogenates of the upper and lower surface slices of the grilled muscles (T_i = 82 °C). A higher content of total free amino acids was seen for the muscle (27.1 mmol kg⁻¹ raw meat) than for the skin (21.7 mmol kg⁻¹ raw meat). The creatine, creatinine and carbohydrate levels in the skin were below the limits of detection. The contents of creatine (31.8-38.7 mmol kg⁻¹) and creatinine (0.24-0.33 mmol kg⁻¹) in the breast muscle were determined. Relatively high levels were seen for glucose (23 mmol kg⁻¹ raw meat) and fructose (10 mmol kg⁻¹ raw meat) in the muscle, with other sugars present at low levels (<2 mmol kg⁻¹ raw meat). For the chicken muscle grilled on a two-plate grill, the contents of total HAs (PhIP, MeIQx, DiMeIQx, Harman and Norharman) were lower with the skin in place than in the muscle grilled without the skin (3.5 μg kg⁻¹vs. 4.8 μg kg⁻¹). Also, during infrared grilling with the skin, lower amounts of HAs were formed than with grilling on the two-plate grill (2.4 μg kg⁻¹vs. 3.5 μg kg⁻¹). On average, the infrared-grilled samples with skin contained 3-fold more total HAs than similar samples without the skin (2.4 μg kg⁻¹vs. 0.8 μg kg⁻¹), with the highest levels seen for PhIP and MeIQx.     

Validation of antibiotics in catfish by on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry

For the first time automated on-line solid phase extraction coupled to liquid chromatography tandem mass spectrometry was developed for the simultaneous determination of 13 antibiotics (sulfonamides and tetracyclines) in catfish. The method proposed was validated according to Commission Decision 2002/657/EC, showing good linearity between 2 and 350 μg kg⁻¹, high recovery (80–99%) and reproducibility (13–20%) values, lower detection limits than 0.1 μg kg⁻¹, and quantification limits under 2.4 μg kg⁻¹ (between 39 and 84 times lower than the MRL fixed by the EU). Moreover, the proposed method was also used to determine sulfonamides and tetracyclines in 16 out of 107 samples, all previously analysed by microbiological screening that gave positive results. Five out of 13 antibiotics were found, having tetracycline the higher occurrence (10 samples); in all cases the concentrations were lower than the MRL established.     

Determination of trace elements in Croatian floral honey originating from different regions

The concentrations of As, Cd, Cu, Hg and Pb were determined in 54 multi-floral honey samples collected from five regions of Croatia during 2009 and 2010. Element contents decreased in the following order: Cu > Pb > As > Hg > Cd. Significant differences in lead and copper levels were observed between regions. Mean levels of elements (μg kg⁻¹) in all honey samples measured were: 19.7 for As, 1.51 for Cd, 1074 for Cu, 2.72 for Hg and 65.2 for Pb. Copper and lead were the most abundant elements in the Centre region, with range and mean contents of 108–41,271 and 3232 μg kg⁻¹ and 22.0–440 and 131 μg kg⁻¹, respectively. The highest element contents were: As 23.8 μg kg⁻¹ in the South region, Cd 2.11 μg kg⁻¹ in the Southwest region and Hg 2.63 μg kg⁻¹ in the Northeast region. The finding that lead contents in Croatian honey were higher than most reported lead levels in honey from other European countries is of particular concern. These indicate that attention must be focused on setting positions for honey production hives in areas distant from highways and railways.     

Pharmacokinetics and residues of tetracycline in crucian carp muscle using capillary electrophoresis on-line coupled with electrochemiluminescence detection

A novel and sensitive determination for tetracycline (TC) in crucian carp muscle was developed by using capillary electrophoresis coupled with electrochemiluminescence (ECL) detection. The conditions affected separation and detection were examined in detail. The linearity range of TC concentration was from 0.005 to 10 μg mL⁻¹ with a correlation coefficient of 0.9992. The detection limit of TC (S/N = 3) was 1.8 ng mL⁻¹. The relative standard deviations of the ECL intensity and the migration time for eleven consecutive injections of 1.0 μg mL⁻¹ TC were 1.6% and 0.8%, respectively. The recovery of TC was 97.8% (n = 5). After administration of 75 mg kg⁻¹ TC, the maximum concentration and peak time of TC in crucian carp muscle were 7.33 mg kg⁻¹ and 8 h, respectively. After administration of TC, TC concentration demonstrated trivial variation in the period from 48 to 96 h.     

Ion chromatographic determination of perchlorate in foods consumed in Hatay region

Recently, the exposure to perchlorate was emphasised as an important risk factor for human and especially newborn health. A number of studies were focused on this matter. In this study, samples of soil, vegetable (cabbage, spinach, lettuce, carrot, tomato, red cabbage), fruit (orange, mandarin, lemon, grapefruit), water, milk and fish were taken from 8 different regions of Hatay (Samanda?, K?r?khan, Reyhanl?, Amik Plain, Dörtyol, Yaylada??, Alt?nözü, Erzin). An ion chromatography system (Shimadzu C196-E039A model) was used to determine the concentrations of perchlorate in the samples. 2.5 mM Phthalic acid and 2.4 mM tris (hydroxymethyl)aminomethane solutions (pH = 4) were used as the mobile phase. A flow rate of 1.5 ml min⁻¹ and oven temperature of 40 °C were used during the analysis. The foods had perchlorate concentrations in the range of 0.236–1.218 μg kg⁻¹. The perchlorate concentration varied from 0.30 ± 0.01 to 0.94 ± 0.02 μg l⁻¹ in milk samples. Perchlorate concentrations were determined to be lower in the drinking waters (0.44 ± 0.03 μg l⁻¹) compared to irrigation waters (0.59 ± 0.03 μg l⁻¹). Perchlorate concentrations of the fish samples were ranged from 0.38 ± 0.01 to 0.61 ± 0.01 μg kg⁻¹.     

Determination of ultratrace levels of selenium in fruit and vegetable samples grown and consumed in Portugal

The selenium content in fruit and vegetable samples from two regions in Portugal were analysed using hydride generation atomic fluorescence spectrometry (HG-AFS) and radiochemical nuclear activation analysis (RNAA) – two analytical methods with very low limits of detection. The lower detection limits of HG-AFS, 3 μg kg⁻¹ and 8 μg kg⁻¹ (according to conditions used for digestion), and for RNAA, 10 μg kg⁻¹, meant that it was possible to determine selenium in samples previously analysed using the replicate sample instrumental nuclear activation analysis (RSINAA) with a higher detection limit associated.     

Analysis of multi-pesticide residues in the foods of animal origin by GC–MS coupled with accelerated solvent extraction and gel permeation chromatography cleanup

A new analytical method was developed to simultaneously determine residues of 109 pesticides (including isomers) in the foods of animal origin. Acetonitrile was selected for accelerated solvent extraction (ASE) for effectively extracting the pesticides from the fatty samples. The cleanup was performed with an automated gel permeation chromatography (GPC) cleanup system. The prepared samples were analysed with GC–MS in the selected ion monitoring mode (SIM) using one target and two qualitative ions for each analyte. Chlorpyrifos-d₁₀ was used as an internal standard. The lowest limit of detection was 0.3 μg kg⁻¹ for some pesticides. The recoveries and relative standard deviations (RSDs) were checked by spiking untreated samples with pesticides at 0.05, 0.1 and 0.2 mg kg⁻¹. The average recoveries of most pesticides were from 62.6% to 107.8%. The precision values expressed as RSD were all ?20.5% (n = 6). Good linearity (r ? 0.99) was observed between 0.05 and 1.5 μg mL⁻¹.     

Synthesis and application of a new functionalized resin for use in an on-line,solid phase extraction system for the determination of trace elements in waters and reference cereal materials by flame atomic absorption spectrometry

The synthesis and characterization of the resin Amberlite XAD-4 functionalized with 2,6-pyridinedicarboxaldehyde and its application in an on-line system for the preconcentration of cadmium, cobalt, copper, lead and manganese prior to determination using flame atomic absorption spectrometry (FAAS) is proposed. Metal ions retained on the modified resin were eluted using 1.0 mol L⁻¹ HNO₃ solution and aspirated directly to the nebulizer–burner system of a FAAS instrument using a flow injection system. Detection limits (3σ) were determined to be 0.13 μg L⁻¹ for Cd, 0.29 μg L⁻¹ for Cu, 0.23 μg L⁻¹ for Mn, 0.58 μg L⁻¹ for Co and 2.19 μg L⁻¹ for Pb using a 10 mL of water sample loading volume. The limits of detection would be 100 times higher with units of μg kg⁻¹ for the solid samples in which their dilution ratios as (volume/weight) were 100. Enrichment factors ranged from 23.6 to 28.9 (for Co and Mn, respectively). The proposed method was successfully applied to determination of the analytes in natural water samples and certified reference materials.     

Comparison of isoflavones composition in seed,embryo, cotyledon and seed coat of cooked-with-rice and vegetable soybean (Glycine max L.) varieties

In order to study the content and composition of isoflavones retained in soybean seed component, obtained each component part the embryo, cotyledon and seed coat tissues of nine different soybean varieties were analyzed for 12 isoflavones using high performance liquid chromatography with photo diode array detector (HPLC-PDA) and were compared to each other. A total average concentration of isoflavone was 2887 μg g⁻¹ in embryo, 575 μg g⁻¹ in whole seed, 325 μg g⁻¹ in cotyledon, and 33 μg g⁻¹ in seed coat. With respect to each tissue of soybean varieties, isoflavone content was highest in Geomjeongkong 2 embryo (5701 μg g⁻¹), Geomjeongolkong whole seed (1321 μg g⁻¹), Heugcheongkong cotyledon (951 μg g⁻¹), and Keunolkong seed coat (56 μg g⁻¹). Isoflavone was least present in Keunolkong embryo (341 μg g⁻¹), Hwaeomputkong whole seed (175 μg g⁻¹), Seonheukkong cotyledon (81 μg g⁻¹), and Seoklyangputkong seed coat (5 μg g⁻¹). Overall, embryo and seed coat of all nine varieties contained isoflavones at the highest and lowest level, respectively. Isoflavones accumulated in the order of malonylglycoside, glycoside, acetylglycoside, and aglycon, among which malonylglycoside was the most abundant form ranging from 66% to 79% of the total isoflavone content in all three tissues. The embryo of cooked-with-rice soybean with black seed coat appears to be the best source of isoflavone.     

Effect of processing and storage of Jameed on conjugated linoleic acid content and fat and cholesterol oxidation

The influence of Jameed processing and storage on fat and cholesterol oxidation, hydrolytic rancidity, and conjugated linoleic acid (CLA) was evaluated by determining peroxide value (PV), 7-ketocholesterol, free fatty acids content (FFAs) and total CLA. Three different sizes of Jameed pieces (ca. 50, 200 and 400 g balls) were used to investigate the influence of storage for 0, 1, 3, 5 and 7 months on the above lipid oxidation parameters. No significant (P>0.05) effect of the Jameed processing steps on lipid changes was found with the exception of the sun drying steps, that caused an increase of PV, 7-ketocholesterol and FFA contents and a decrease in CLA content. This trend was also observed during storage of Jameed at room temperature and kept exposed to light and atmospheric air. The PV values of the 50, 200 and 400 g balls after 7 months of storage were 35.3, 19.4 and 20.4 meq O₂ kg⁻¹ of fat, that were 17, 11 and 12 times higher compared with the corresponding values of the fresh samples (1.9 meq O₂ kg⁻¹ of fat ). The 7-ketocholesterol of the tested samples increased from about 5.7 μg g⁻¹ to 210, 120 and 125 μg g⁻¹ for the 50, 200 and 400 g balls, respectively. FFA content increased remarkably during storage, from about 1.3 g kg⁻¹ at the beginning of storage to 8.6 g kg⁻¹ of fat after 7 months with no significant (P>0.05) effect for the size of Jameed pieces on FFAs content. On the contrary, a decrease of about 43%, 26% and 26% of the original value (5.7 mg kg⁻¹ of fat) in CLA content was found for the stored Jameed pieces of 50, 200 and 400 g, respectively.     

Quantification of organophosphate insecticides and herbicides in vegetable samples using the “Quick Easy Cheap Effective Rugged and Safe” (QuEChERS) method and a high-performance liquid chromatography-electrospray ionisation-mass spectrometry (LC-MS/MS) technique

A Quick Easy Cheap Effective Rugged and Safe (QuEchERS) extraction was developed and followed by selective analysis using a liquid chromatography-mass spectrometry method for the quantification of eighteen pesticides in vegetable samples. This method was accurate (?99.5%), and it exhibited limits of detection and quantification values in the 0.006-0.091 and 0.020-0.314 μg kg⁻¹ ranges, respectively. Furthermore, the coefficients of variations (?0.9999) were less than 1% at the low μg kg⁻¹ end of the method. Mean recoveries ranged between 94% and 102%, and relative standard deviations were below 10%. Based on these results, the methodology was proven to be highly efficient, robust, and suitable for monitoring the maximum residue limits (MRL) compliance of a wide range of commodity/pesticide combination. This method was successfully applied to the analysis of vegetable samples that were collected from different government farmers’ markets and street shops in urban areas. The presence of target pesticides was found in the range of 0.016 and 50.85 μg kg⁻¹.     

Determination of tetracyclines in multi-specie animal tissues by pressurized liquid extraction and liquid chromatography–tandem mass spectrometry

A specific, sensitive and robust pressurized liquid extraction (PLE) and liquid chromatography tandem mass spectrometry (LC–MS/MS) method for determining tetracycline, chlortetracycline, oxytetracycline and doxycycline in bovine, swine, poultry and lamb muscle tissues is presented. PLE was performed using an ASE^® 200 from Dionex and water as extractant, followed by solid-phase extraction (SPE) using an Oasis HLB cartridge. The method was validated for beef, chicken, pork and lamb meat in compliance with the requirements set by Commission Decision, 2002/657/EC [Commission Decision 2002/657/EC (2002). Implementing Council Directive 96/23/EC concerning the performance of analytical methods and interpretation of results. Official Journal of European Communities, L239, 66–98. (Available at: <http://europe.eu.int>)]. The average recoveries of the different meat samples, spiked with the four tetracyclines at three levels (1, 100 and 200 μg kg⁻¹ of each tetracycline), were always higher than 89% with intraday and interday precision lower than 15% and 17%, respectively. A good linearity was established for the four tetracyclines in the range from 5 to 10,000 μg kg⁻¹ with r > 0.995. The limits of quantification (LOQs) were between 0.5 and 1 μg kg⁻¹, which are well below the tolerance levels set by the European Union. The decision limit (CCα) and the decision capability (CCβ) were in the range 101–116 and 112–130 μg kg⁻¹, respectively. Compared with previous methods, sample preparation time required for the analysis and LOQs, are reduced. The method demonstrated its successful application for the analysis of 100 meat samples. Two samples of beef and one sample of chicken out of 25 of each type tested positive while none of 25 samples of either, lamb or pork, tested positive.     

Daily selenium intake in a moderate selenium deficiency area of Suzhou,China

In this study the daily dietary Selenium (Se) intake in Suzhou was investigated to determine whether residents in such a developed region were susceptible to moderate Se deficiency. Concentrations of Se in typically consumed foods in Suzhou were determined. Based on food Se content and the daily per capita consumption, the estimated Se intake in Suzhou was 43.9 ± 3.8 μg day⁻¹. The results revealed that pork and cereals were the major sources of Se daily intake and contributed 24.7% and 22.6% to the daily Se intake, respectively. The Se content in hair of local residents was 389.9 ± 103.6 μg kg⁻¹ for male and 322.9 ± 101.8 μg kg⁻¹ for female. A significant linear correlation between the daily Se intake and the hair Se concentration was established. The hair Se concentration could be used to bioindicate the level of Se intake for longer period.     

Determination of diquat and paraquat in olive oil by ion-pair liquid chromatography–electrospray ionization mass spectrometry (MRM)

For the first time a method for determination of herbicides diquat (DQ) and paraquat (PQ) in olive oil was developed utilising liquid chromatography–electrospray ionization mass spectrometry (MRM). n-Hexane/10 mM HFBA aqueous solution partitioning was used as the extraction method. Separation was carried out in an Xterra C8 column (100 × 21 mm, 3 μm), using the gradient mode. Solvent A was a HFBA aqueous solution (5 mM, pH 2) and solvent B acetonitrile/methanol 75/25 (v/v). Peaks used for quantification were m/z = 157 (diquat) and m/z = 158 (paraquat). Detection limit found for both diquat and paraquat was 4 μg kg⁻¹. The method can also be applied for determination of chlormequat (CQ, quantification peak m/z = 58), the detection limit being 0.3 μg kg⁻¹. Such limits are clearly lower than the MCLs commonly applied to olive oil as reference criteria (5 times MCLs in olives). Good reproducibilities (day to day and run to run) were obtained.     

Determination of pyrethroids in porcine tissues by matrix solid-phase dispersion extraction and high-performance liquid chromatography

An effective matrix solid-phase dispersion (MSPD) extraction for determination of two pyrethroids (cypermethrin and deltamethrin) in porcine tissues (liver, muscle, heart and kidney) is described. A neutral alumina-based MPSD column was used for extraction of analytes. The high-performance liquid chromatography and ultraviolet detector was applied using a reverse-phase C₁₈ column and acetonitrile-water (85:15, v/v) was used as mobile phase. The good linear fit curve ranging from 0.05 to 50 μg mL⁻¹ for cypermethrin (CM) and deltamethrin (DM) was obtained with a regression coefficient (r) of 0.999. Recoveries at 0.2 and 0.5 μg g⁻¹ levels were between 83.5% and 109%. The limits of detection and quantification were: 0.01 and 0.026 μg g⁻¹ for CM, 0.017 and 0.056 μg g⁻¹ for DM, respectively. The proposed method was successfully applied to the determination of the pyrethroids in porcine tissues.     

Determination of methylmercury in marine and freshwater fish in Ghana using a combined technique of dithizone extraction and gas–liquid chromatography with electron capture detection

Concentrations of methylmercury (MeHg) residues were determined in different marine and freshwater fishes from Ghana. Samples were treated with ethanolic potassium hydroxide in water bath at 100 °C for 1 h. After neutralising with HCl and washing with hexane, MeHg was extracted with dithizone in toluene, cleaned up and determined by gas chromatography with electron capture detection (GC–ECD). The method was sensitive with good precision, detection limit of 0.0005 μg g⁻¹ (0.5 μg kg⁻¹) and provided good separation for organomercury compounds. The validity of the method was established using dogfish muscle certified reference material, DORM-2. The method was applied to different fish species. Concentration of MeHg in the edible muscle tissue of the tested fish ranged from 0.009 to 0.107 μg g⁻¹ wet weight. The concentrations of MeHg in the fish samples obtained do not however, constitute any significant mercury exposure to the general population through consumption of the tested fish species.