Food Analysis Performance Assessment Scheme Research Articles

Development of a new method for extracting histamine from marine fish flesh using the salting-out technique.

A simple and practical method was developed to extract histamine from fish products using sodium chloride (NaCl). After obtaining a saline extract from fish samples, histamine was derivatized by a condensation reaction with ortho-phthalaldehyde. Fluorescence intensity was measured by a fluorimeter. The first part of this work concerned a solid-liquid extraction tested with samples from the food analysis performance assessment scheme. The best histamine extraction yield (97%) was obtained using an extraction time of 4 minutes, a temperature of 40°C, and a NaCl/water ratio of 41% (w/w). The second part focused on a liquid-liquid extraction carried out on standard solutions of histamine (45, 90, and 180 mg/kg). The use of NaCl (41%) and trichloroacetic acid [(TCA) 10%] did not show any significant difference in extraction yield. The yield obtained was 99.15-100.1% for TCA (10%) and 98.65-99.45% for NaCl (41%). The validation criteria (repeatability and reproducibility) were checked by evaluating the reliability of the method. Extraction using NaCl has proven to be an interesting alternative method for the extraction of histamine from fish, as it is reliable, inexpensive, and less hazardous.

한국형 총식이조사 및 UV/태양광 조사 버섯에서의 비타민 D 분석

This study was conducted to evaluate vitamin D intake of Koreans in a total diet study (TDS) and to determine the effect of irradiation on vitamin D synthesis in mushrooms. For analysis, sample were saponified and extracted with hexane, and vitamin D was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on the validation results, the recovery of the National Institute of Standards and Technology (NIST) standard reference sample (SRM) 1849a was 96.7% and the z-score of −1.6 was obtained by the Food Analysis Performance Assessment Scheme (FAPAS) proficiency test (PT) 21115. Vitamin D2 was not detected in any samples, and the highest level of vitamin D3 was detected in mackerel and anchovies ranging from 24.2 to 120.2 μg/kg. The mean daily intake of vitamin D was 0.99 μg/day, as estimated from the vitamin D contents of the analyzed foods and their corresponding intake. The adequate intake (AI) of vitamin D based on the Dietary reference intakes for Koreans provided by the Ministry of Health and Welfare is 5-15 μg/day for Koreans aged 6 to 75 years. Compared with this AI, vitamin D intake of Koreans estimated in this study was inadequate. For that, the increased vitamin D content in ultraviolet (UV)/sun light irradiated mushrooms warrants further research to increase vitamin D intake of Koreans through diet.

Determination of Heavy Metal Concentration in Herbal Medicines by GF-AAS and Automated Mercury Analyzer

This study was conducted to analyze and compare the concentrations of heavy metals in 430 different products of 20 types of herbal medicines available in the domestic market in Korea by Graphite Furnace– Atomic Absorption Spectrometry (GF-AAS) and automated mercury analyzer. The accuracy for lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg) was in the range 92.67-102.56%, and the precision was 0.21-6.00 relative standard deviation (RSD%), which was in compliance with the Codex acceptable range. Furthermore, the Food Analysis Performance Assessment Scheme (FAPAS) quality control (QC) material showed a recovery range of 96.7- 102.0% and 0.33-4.93 RSD%. The average contents (μg/kg) of Pb, As, Cd, and Hg in herbal medicines were 254.9 (not detected (N.D.)-2,515.2), 171.0 (N.D.-2,465.2), 99.2 (N.D.-797.1), and 6.0 (N.D.-83.6), respectively. Based on the quantitative analysis results, the heavy metal contents of 20 types of herbal medicines distributed in Korea are within the acceptable range according to the standards issued by the Ministry of Food and Drug Safety (MFDS). By using the manufacturer of herbal products as the standard for QC, the Pb, As, Cd, and Hg contents were investigated in the packaging process just before distribution to determine the actual conditions of residual heavy metals in herbal medicines. Thus, these result may contribute to monitoring the QC of herbal medicines distributed in Korea and could provide basic data for supplying safe herbal medicines to the public.

Application, development, and challenges of capillary electrophoresis in disease prevention and control

Since the advent of commercial instruments in 1989, capillary electrophoresis (CE) has advanced considerably, with improvement in reproducibility and accuracy in many application fields. CE is predominantly used in research on disease prevention and control, and hygienic chemical inspection. The applications of CE range from assessment of inorganic anions and cations in drinking water to that of biological macromolecules, such as nucleic acids, in pathogenic microorganisms. Since the analytical capacity of CE ranges from inorganic ions to cell, it has become an indispensable technique in this field, particularly in public health emergency and epidemic management. Universal non-targeted analyses to detect possible pathogens, and the capability of rapid and accurate testing of large numbers of specimens are required. In the analyses of polymerase chain reaction (PCR) products, nucleic acid sequencing, mutation detection and genotyping, food-borne disease pathogens, and vaccine analyses, CE methods characterized by high through-put and sensitivity are necessary. In the public health sector, CE is essential in the analyses of food (including emergency analyses for food poisoning), cosmetics, and disinfectants. Satisfactory results of the FAPAS (Food Analysis Performance Assessment Scheme) and domestic proficiency tests indicated the accuracy of CE in quantitative analyses. Application of CE in disease prevention and control is challenged by a number of new molecular biological methods, as optimizing CE methods may not be feasible, and results are difficult to interpret. CE methods, including transformation of peaks to identification of pathogens, can be an arduous task. Thus, end-users prefer using commercialized CE systems and reagents in their routine work. Alternatively, CE methods for analysis of small molecules in product analyses, such as food safety, cosmetics and disinfectant testing, is commonly performed. A plethora of studies published within the decade, indicate that CE is still an active research area in hygienic chemical inspection. To a large extent, CE has not been used for routine analysis in the centers for disease control and prevention, accredited laboratories in China, nor regulatory agencies worldwide. This may be due to the lack of practical protocols for the standards, and the misconceptions regarding the ease of use of CE, which could have hindered its widespread application. Although CE is an environmental friendly technique with minimal usage of toxic chemicals, few standard methods of CE exist in agriculture, environmental protection, food, beverage, chemical, and pharmaceutical industries in the United States, Britain, Europe, Japan, India, Brazil, Russia, and China. Since 2002, CE was used in our laboratory to analyze a large variety of samples. We found that once the CE method has been fully verified and described in detail, it was easily standardized. It is not necessary to screen the equivalent chromatographic column, or to use a specific liquid chromatographic (LC) column. This can effectively circumvent the challenge of shifting peak orders caused by different LC column selectivity. Once combined with general, high sensitivity detectors, CE can be used in the detection of bacteria or viruses in food safety, and play a greater role in the field of disease prevention and control. In the present review, applications of CE in nucleic acid detection for viruses and bacteria, analysis of vaccines, routine testing on food, dietary supplements, medical foods, cosmetics and disinfectants, proficiency tests, and emergency analyses of food poisoning were summarized. The applications and challenges of CE in the field of disease control and prevention were analyzed, and development of this technique was prospected.

Development of SPE clean-up procedure for acrylamide determination from potato-based products by GC-MS/MS

Abstract The aim of this work was to develop an analytical method for determining acrylamide in potato-based products by gas chromatography and tandem mass spectrometry analysis (GC-MS/MS) using solid-phase extraction (SPE) clean-up. Different conditions for extraction and clean-up of AA extracts were studied on a potato crisps reference material (RM) with the value of 625 ± 45 μg/kg: the solvent volume used for AA elution, the extraction water temperature, the volume of hexane used, and also the addition of Carrez solutions. The SPE cartridge sorbents contain silica-based C-18 groups (anion and cation exchangers) and polymers (polystyrene-divinylbenzene). After SPE clean-up, extracts were derivatized with bromine compounds. A good efficiency for AA extraction and a cleaned-up extract from this matrix were obtained when the SPE procedure was carried out with water at room temperature, simultaneous with hexane, without Carrez solutions, by using two types of SPE cartridges (Isolute Multimode; Isolute ENV+), and 5 mL of elution solvent. The SPE clean-up procedure functionality was demonstrated by the results obtained in the Food Analysis Performance Assessment Scheme proficiency test (z-score: −0.8) on French fries (precooked) matrix and also by comparative analysis with a laboratory procedure, validated and accredited on cereal-based food matrices, in which liquid–liquid extraction and clean-up through a florisil column were realized (RSD(R) = 2.23–5.10%).

Rapid determination of mercury in dust emission using Cold Vapour Inductively Coupled Plasma Optical Emission Spectrometer (CV ICP OES)

ABSTRACT Mercury emissions generated by the human activities were ranged between 60% and 90% from total mercury content determined in some industrialised regions. It is well known that urban dust has adverse health effects, being related to respiratory diseases. In this study, Cold Vapour Inductively Coupled Plasma Optical Emission Spectrometer (CV ICP OES) was optimised, validated, and applied in routine analysis for the determination of vapour mercury in dust emission samples collected from different Egyptian cement plants. The estimated detection limit, practical quantification limit, linearity (linear dynamic ranges and method linearity), accuracy (trueness and precision), and measurement uncertainty parameters were studied under optimised (CV ICP OES) conditions. The method showed that the estimated detection limit was found to be equal to 0.12 µg/L, and the quantification limit was found to be equal to 0.5 µg/L. The mean recoveries ± standard deviations at different levels were varied between 88.60 ± 8.18 and 110.20 ± 5.93% with a coefficient of variation expressed as relative standard deviation ranged from 0.64 and 7.25%. The method trueness was confirmed by using four different certified references materials purchased from Food Analysis Performance Assessment Scheme (FAPAS) and all obtained results were within satisfactory ranges and had acceptable recovery and Z-score values. The method precision, in terms of relative standard deviation (RSD), was being below 7.74%. The method uncertainty expressed as expanded uncertainty was found to be ≤ 16.11%. The results obtained make the method suitable for accurate determination of vapour mercury in dust emission samples at low concentration. The validated method was used for the determination of mercury in fifty-eight dust emissions samples and the results were compared with the maximum limit stated by European standard on the incineration of waste.

Development of a sensitive polyclonal antibody-based competitive indirect ELISA for determination of citrinin in grain-based foods

ABSTRACTA sensitive competitive indirect enzyme-linked immunosorbent assay (ciELISA) was developed for the detection and quantification of citrinin (CIT) in grain-based food samples. The limit of quantification (IC20) of the established method was 0.10 ± 0.02 ng mL−1, with the limit of detection (IC10) being 0.04 ± 0.007 ng mL−1 in wheat and corn flour matrices with a coefficient of variation (CV) less than 20%. The assay was very specific to CIT and showed no cross-reactivity with other mycotoxins (OTA, T-2 toxin, HT-2 toxin, DON, patulin and zearalenone). In spiked wheat and corn flours, the recoveries ranged from 86.6% to 115.6% with CVs of less than 20%. The effectiveness of this method was verified by participating in a proficiency test (PT) from the Food Analysis Performance Assessment Scheme (FAPAS) 17181 corn flour. A successful z-score (−0.6) for this PT sample showed that the present method is comparable to the instrumental methods used by other laboratories in the PT testing scheme. A small survey of grain-based foods was conducted using this method and CIT was detected in 43% of the samples up to a concentration of 17.7 ng g−1. This method is suitable for sensitive and rapid quantitation of citrinin in wheat and corn matrices.

Method validation for direct determination of some trace and toxic elements in soft drinks by inductively coupled plasma mass spectrometry

ABSTRACT The consumption of soft drink beverages has increased in the last few years around the world and it is related to the diversity of brands and flavours available, increasing also the risk of ingestion of compounds considered non-beneficial to the health of consumers. In this study, fast, easy and simple method of analysis for direct determination of As, Pb, Cd, Sb, Hg, Cu, Zn, Fe, Al, Cr, Sn, Co, Mn and Ni in soft drink samples using quadrupole inductively coupled plasma mass spectrometry (Q-ICP–MS) was validated. The estimated detection limits, practical quantification limits, linearity (linear dynamic ranges and method linearity), accuracy (trueness and precision) and measurement uncertainty parameters were studied under optimised (Q-ICP–MS) conditions. The method showed that the estimated detection limits were varied between 0.02 and 2.403 µg/L, and the quantification limits were varied between 0.5 and 20 µg/L. The mean recoveries ± standard deviations at different spiking levels were varied between 75.03 ± 0.62% and 117.07 ± 2.83% and the coefficients of variation were varied between 0.49% and 9.79%. The method trueness was confirmed by using four different certified reference materials (soft drinks and treated water) purchased from FAPAS (Food Analysis Performance Assessment Scheme) and all obtained results were within satisfactory ranges and had acceptable recovery and Z-score values. The method precision, in terms of relative standard deviation, was below 4.88%. The method uncertainty expressed as expanded uncertainty of all validated elements was found to be ≤22.52%. The results obtained make the method suitable for accurate determination of validated elements in different kinds of soft drink samples at these low concentration values. Validated method was used for the determination of metallic contaminants in 40 commercial soft drink samples and the results were compared with the provisional guideline of the elements stated by Egyptian, WHO and European standards in drinking and potable bottled natural mineral water.

Determination of residual glyphosate and aminomethylphosphonic acid in wheat flour and oats samples by non-derivatization method based on ultra-performance liquid chromatography-high resolution mass spectrometry

A rapid and accurate analysis method based on ultra-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) was developed for the determination of residual glyphosate (GLY) and aminomethylphosphonic acid (AMPA) in wheat flour and oats samples. The wheat flour and oats samples were firstly subjected to vortex and ultrasound extraction; then, the extract solution was purified by MCX solid-phase extraction (SPE) cartridges as well as protein precipitation using acetonitrile. The chromatographic separation was carried out on a Dikma Polyamino HILIC column (150 mm×2.0 mm, 5 μm) by linear gradient elution procedure using 5 mmol/L ammonium acetate in water (pH=10.5) and acetonitrile as the elution solvent. An electrospray ion source in negative mode and parallel reaction monitor (PRM) mode was used for quantification by the internal standard method. The instrument conditions for liquid chromatography (LC) and HRMS, and the sample pretreatment conditions for GLY and its metabolite AMPA were systematically optimized. In addition, the matrix effect and injection system residue were investigated, and a comparison of different analytical methods was carried out. The results indicated that GLY and AMPA showed good linearities in the range of 5.0-100.0 μg/L with coefficients (R2) higher than 0.999. The limits of detection (LODs) were found to be 0.005 and 0.05 mg/kg for GLY and AMPA, respectively. The recoveries of GLY and AMPA in the wheat flour and oats samples were in the range of 93.8%-115% and 89.8%-110% at the spiked levels of 0.1, 0.5, and 2.0 mg/kg, respectively, while the relative standard deviations (RSDs) were all less than 10%. The results of the matrix effect test revealed that the matrix inhibition effect could be reduced by using an isotopic internal standard with the matrix effect parameter |η|<3%. Moreover, the injection system residue was effectively controlled with a residual level of less than 1.0%. A comparison of the developed method with the reported derivatization method indicated little difference, with RSDs of 2.19% and 3.07% to the assigned value, respectively. The established analytical method was used for the Food Analysis Performance Assessment Scheme (FAPAS) proficiency test (No. 09122, GLY in oats), and the results were satisfactory with a z value of 0.2. Moreover, the result obtained using this method was very closed to the assigned value of the FAPAS QC sample, with a recovery of 102.2% (No. T09119QC, GLY in wheat flour). The proposed method is fast, simple, sensitive, and accurate, and it can be applied for the daily monitoring of GLY and its metabolite AMPA in wheat flour and oats samples.

Determination of macro, micro, trace essential, and toxic elements in Garcinia cambogia fruit and its anti-obesity commercial products.

Garcinia (Clusiaceae) species are traditionally used as flavoring agents in curries and to cure several human health complications. This study investigated 31 macro, micro, and trace elements in microwave-assisted digested samples of Garcinia cambogia fruit and its anti-obesity commercial products by inductively coupled plasma-optical emission spectroscopy (ICP-OES) and inductively coupled plasma-mass spectrometric (ICP-MS) techniques. The methods were also validated using the coefficient of determination (R2 ), limits of detection and quantification (LOD, LOQ), precision (CV%), analysis of certified reference materials, spiking recovery experiments, and participation in an accredited laboratory proficiency test organized by Food Analysis Performance Assessment Scheme (FAPAS). Quality assurance confirmed that the methods were efficient and in accordance with criteria set by the Association of Official Analytical Chemists (AOAC). In the elemental analysis, the analyzed macro, micro, and trace essential elements were present in appreciable concentrations, which could meet the human nutritional requirements. Traces of toxic elements were within safe limits. From the results of the current study, the fruit and its commercial products could be considered potential sources of mineral elements without posing any threats to consumers. © 2018 Society of Chemical Industry.

Development of Enzyme-Linked Immunosorbent Assay for Analysis of Total Aflatoxins Based on Monoclonal Antibody Reactive with Aflatoxins B1, B2, G1 and G2.

A direct competitive enzyme-linked immunosorbent assay (dc-ELISA) was developed for the determination of total amount of aflatoxin B1, B2, G1 and G2 (AFB1, AFB2, AFG1 and AFG2), using a mouse monoclonal antibody that shows similar reactivity to each of these AFs. The working range of the developed dc-ELISA was 50-230 pg/mL for AFB1, 50-270 pg/mL for AFB2, 60-390 pg/mL for AFG1 and 65-700 pg/mL for AFG2. The recovery of AFs from spiked roasted peanuts was 98％. Further, when 4 samples actually contaminated with AFB1, AFB2, AFG1 and AFG2 were examined, the results of dc-ELISA were highly correlated with the values assigned by the Food Analysis Performance Assessment Scheme. The developed dc-ELISA appears to be suitable for the determination of total AFs at concentrations around the maximum permitted level (10 μg/kg for all foods) in Japan.

An improved method for the measurement of 3‐monochloropropanediol esters by matrix solid‐phase dispersion supported liquid–liquid extraction

Summary3‐Monochloropropanediol (3‐MCPD) esters are contaminants produced from the high‐temperature processing of edible oils. The accurate measurement of 3‐MCPD using an easy‐to‐follow and reliable method that uses a readily available instrument is important. Here, we report an acid transesterification heptafluorobutyrylimidazole (HFBI) derivatisation method for the accurate measurement of 3‐MCPD esters in edible oils. We developed a dispersed matrix solid‐phase supported liquid–liquid extraction (DMSP‐SLE) system to remove impurities. Both the transesterification and DMSP‐SLE conditions were optimised. A good linear relationship was obtained within the range of 0.05–10 mg kg−1 (R2 ≥ 0.999) in both blank solvent and an oil sample. The limit of detection was 20.36 μg kg−1. The average recovery of the 3‐MCPD esters spiked at 0.5, 1.0 and 2.0 mg kg−1 into a blank oil matrix was in a range from 105.09 ± 2.77% to 120.16 ± 10.88%. The method we developed was further confirmed by performing detection on a Food Analysis Performance Assessment Scheme (FAPAS) sample.

Chloramphenicol stereoisomers need to be distinguished: consequences observed from a proficiency test

ABSTRACTAlthough the use of chloramphenicol (CAP) as a veterinary drug is banned in the European Union and many other countries, monitoring for CAP residues in food is routine. Positive detections are few, but taken extremely seriously. European Union laboratories analysing for CAP should validate methods according to European Commission Decision 2002/657/EC, must be accredited to ISO 17025, and will generally participate in proficiency testing (PT) schemes, such as those offered by the Food Analysis Performance Assessment Scheme (FAPAS®). The FAPAS PTs aim to cover a wide range of relevant matrices including honey, prawns, fish, milk and kidney. Test materials are prepared either by animal dosing studies or by spiking raw matrix. The most common method reported by FAPAS participants used to screen for CAP residues is LC-MS/MS, but ELISA kits are increasingly being used. A recent PT round highlighted that the result obtained might be correlated with the type of analytical method being employed. Follow-up investigations have demonstrated that some of these variations in data are a function of the different stereoisomeric forms of CAP. This paper discusses the implication of this research on method validation requirements and European Union legislation.

The Use of Biochip Array Technology for Rapid Multimycotoxin Screening.

The main known groups of mycotoxins are aflatoxins, fumonisins, ochratoxins, type A trichothecenes (T-2 toxin and HT-2 toxin), type B trichothecenes (deoxynivalenol), and zearalenones. They are harmful to humans, domestic animals, and livestock. In Europe, maximum permitted limits for aflatoxin B1 are set, and guidance levels are recommended for the other mycotoxins. This study applied biochip array technology to semiquantitative multimycotoxin screening at different levels to facilitate the verification of the compliance of feed material with acceptable safety standards. This application was developed and validated based on European Commission Decision No. 2002/657/EC. After a single generic sample-preparation method, simultaneous competitive chemiluminescent immunoassays were used and applied to the Evidence Investigator analyzer. The r and within-laboratory R values showed low overall CVs (10.6 and 11.6%, respectively). Low matrix effect and, consequently, low decision limits and detection capabilities proved the high sensitivity of the technology. The overall average recovery was 104%. Samples (n = 16) investigated within the Food Analysis Performance Assessment Scheme (FAPAS) program showed excellent correlation to assigned values. FAPAS proficiency-testing feed samples (n = 10) were within the schemes' z-score ±2 range. The authentic feed samples survey showed excellent correlation with LC-MS/MS. This application is, therefore, reliable and represents an innovative, cost-effective, and multianalytical tool for mycotoxin screening.

Vitamin B5 and B6 Contents in Fresh Materials and after Parboiling Treatment in Harvested Vegetables

This study was aimed to determine the changes in vitamin B5 and B6 contents compared to fresh materials after parboiling treatment of the main vegetables consumed in Korea. The specificity of accuracy and precision for vitamin B5 and B6 analysis method were validated using highperformance liquid chromatography (HPLC). The recovery rate of standard reference material (SRM) was excellent, and all analysis was under the control line based on the quality control chart for vitamin B5 and B6. The Z-score for vitamin B6 in food analysis performance assessment scheme (FAPAS) proficiency test was -1.0, confirming reliability of analytical performance. The vitamin B5 and B6 contents in a total of 39 fresh materials and parboiled samples were analyzed. The contents of vitamin B5 and B6 ranged from 0.000 to 2.462 and from 0.000 to 0.127 mg · 100g -1 , respectively. The highest contents of vitamin B5 and B6 were 2.462 mg · 100g -1 in fresh fatsia shoots (stem vegetables), and 0.127 mg · 100g -1 in fresh spinach beet (leafy vegetables), respectively. Moreover, the vitamin B5 and B6 contents for parboiling treatment in most vegetables were reduced or not detected. In particular, the contents of vitamin B5 in parboiled fatsia shoots and vitamin B6 in parboiled yellow potato and spinach beet were decreased 20- and 4-fold compared with fresh material, respectively. These results can be used as important basic data for utilization and processing of various vegetable crops, information for dietary life, management of school meals, and national health for Koreans.

Direct determination of fatty acid esters of 3-chloro-1, 2-propanediol in edible vegetable oils by isotope dilution - ultra high performance liquid chromatography - triple quadrupole mass spectrometry

A selective and sensitive ultra-high performance liquid chromatography - triple quadrupole mass spectrometry (UHPLC-MS/MS) method coupled with matrix solid phase dispersion (MSPD) extraction was developed for the direct determination of fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible vegetable oils. The method integrated the isotope dilution technique, MSPD extraction and UHPLC - MS/MS analysis with multi-reaction monitoring mode (MRM). Matrix-matched calibration curves showed good linearity within the range of 0.01–10mgL−1 with the correlation coefficient not less than 0.999. Limits of detection (LODs) and limit of quantification (LOQs) of the 3-MCPD esters fell into the range of 0.0001–0.02mgkg−1 and 0.0004–0.05mgkg−1, respectively. The recoveries for the spiked extra virgin olive oils ranged from 94.4% to 108.3%, with the relative standard deviations (RSD) ranging from 0.6% to 10.5%. The method was applied for the oil sample (T2642) of the official Food Analysis Performance Assessment Scheme (FAPAS) in 2014 and other real samples from supermarket, and the results showed that the present method was comparative to the gas chromatography-mass spectrometry (GC-MS) method based on the improved German Society for Fat Science (DGF) standard method C-III 18 (09) except for palm oil.

Simultaneous Determination of 11 Food Additives by Micellar Electrokinetic Capillary Chromatography

A micellar electrokinetic chromatographic (MEKC) method was developed for simultaneous determination of 11 food additives which are commonly used in beverage, yogurt, and candied fruit samples. An uncoated fused-silica capillary with 50 μm i.d. and 70 cm total length (effective length: 60 cm) was used for the separation. The separation buffer consisted of 20 mmol/L sodium tetraborate, 42 mmol/L boric acid (pH 8.83), and 100 mmol/L sodium deoxycholate. The separation voltage was 23 kV, and the detection wavelength was 214 nm. The limits of detection were in the ranges of 0.25 to 2.5 mg/L. The corrected peak areas (Ac) and the concentrations of the 11 additives showed linear relationships within the ranges of 0.6–400 mg/L with linear correlation coefficients (r) above 0.99. The recoveries ranging from 81.6 to 115.0 % with relative standard deviations (RSDs) all lower than 5 % were obtained, which demonstrated the accuracy of the proposed method. A Food Analysis Performance Assessment Scheme (FAPAS®) proficiency test sample was analyzed. The results showed that the current method with simple sample pretreatment could meet the needs for routine analysis of the 11 additives in beverage, yogurt, and candied fruit samples.

Simultaneous determination of ten preservatives in ten kinds of foods by micellar electrokinetic chromatography

An improved micellar electrokinetic capillary chromatography method (MEKC) for the simultaneous determination of ten preservatives in ten different kinds of food samples was reported. An uncoated fused-silica capillary with 50μm i.d. and 70cm total length was used. Under the optimized conditions, the linear response was observed in the range of 1.2–200mg/L for the analytes. The limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) ranging from 0.4 to 0.5mg/L and 1.2 to 1.5mg/L, respectively were obtained. The method was used for the determination of sorbic and benzoic acids in two FAPAS® (Food Analysis Performance Assessment Scheme) proficiency test samples (jam and chocolate cake). The results showed that the current method with simple sample pretreatment and small reagent consumption could meet the needs for routine analysis of the ten preservatives in ten types of food products.

Revealing the Spatial Distribution of Inorganic Elements in Rice Grains

Femtosecond laser ablation (fs LA) was used in this study to identify pollution by heavy metals and the distribution of elemental nutrients at different rice milling ratios. Polished rice (degrees of milling of 3, 5, 7, 9, and 11) was collected from major Korean supermarkets and one sample thereof was selected. An internal quality control experiment was conducted using a rice flour certified reference material from the Korea Research Institute of Standards and Science (KRISS CRM) for the evaluation of the efficacy. To assess the effectiveness of the analysis method, the reliability was validated using a food analysis performance assessment scheme (FAPAS), with chili powder serving as an external quality control. The results of the analysis of the inorganic elements Ti, Ca, Al, Fe and Mn in white and brown rice with degrees of milling of 3, 5, 7, 9 and 11 using ICP-MS, ICP-OES and AAS revealed contents of 0.40, 49.2, 2.43, 5.36 and 10.3 mg/kg in white rice and 0.59, 78.0, 7.52, 11.0 and 18.5 mg/kg in brown rice, respectively. Among the elements, there were remarkable differences in the measured contents. By comparing the contents of the elements at different degrees of milling, Ti, Co, As, Ca, Al, Cu, Fe, and Mn were determined to be distributed on the surface of the rice grains, whereas the contents of Cd and Pb increased toward the center of the rice grains, and Si was evenly distributed. After the quantitative analysis of rice samples polished to different degrees of milling, Ca and Al, which were contained in large amounts, and Si were analyzed with specificity by fs LA. The results show that Ca and Al were distributed in the rice husk (protective covering of rice) and Si was distributed in all parts of the rice.

Application of Accelerated Solvent Extraction for Simultaneous Isolation and Pre-cleaning Up Procedure During Determination of Polycyclic Aromatic Hydrocarbons in Smoked Meat Products

A simplified method, following European Commission legislation, for the determination of four polycyclic aromatic hydrocarbons (PAH4)—benzo[a]pyrene (B[a]P), benzo[a]anthracene (B[a]A), chrysene (CHR) and benzo[b]fluoranthene (B[b]F)—in smoked meat products is elaborated. The novelty of the method is in the simultaneous extraction and pre-separation of PAH4 fractions using accelerated solvent extraction equipment (ASE 350), in which the sample was mixed with the same amount of the drying material poly(acrylic acid), partial sodium salt-graft-poly(ethylene oxide), applied a on silica gel bed (optimum sample fat/silica gel ratio = 0.05) and extracted in an ASE cell using n-hexane at 100 °C and 10 MPa at a static time of 10 min. The flush volume was 60 %, the purge time was 120 s and this static cycle was repeated three times. Then, the extract was evaporated in a water bath to dryness (40 °C) using a nitrogen stream, dissolved in acetonitrile and determined by HPLC in isocratic regime using mobile phase acetonitrile/water 70:30 (v/v). A fluorescence detector operated at excitation/emission wavelength 260/410 nm for B[a]P, 275/385 nm for B[a]A and CHR, and 256/446 nm for B[b]F, respectively. The method passed through an in-house validation procedure and met all set out criteria of European Commission Regulation No. 836/2011 such as limit of detection (LOD), limit of quantification (LOQ), linearity, repeatability, intermediate precision and recovery. This method is more operative and consumes less time, solvents and materials in comparison with current methods composed of sole ASE extraction and additional pre-separation procedures. Finally, the suitability of the method was tested on Food Analysis Performance Assessment Scheme (FAPAS)-certified material (smoked meat products) and the results confirmed accordance of measured data with the declared PAH content.