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A method for analyzing fluoroquinolone antibiotics, viz. enrofloxacin and ciprofloxacin, in chicken meat has been developed with the aim of reducing the total analysis time. Certified reference materials (CRMs) for the chicken meat powder, i.e. KRISS CRM 108-03-003 and KRISS CRM 108-03-004, were used for method development. Isotope dilution ultra-performance liquid chromatography–mass spectrometry (ID-UPLC-MS) was employed for sample analysis. The liquid chromatography (LC) conditions were optimized with an “in-sample addition” method using a trace amount of ethylenediaminetetraacetic acid (EDTA), in which EDTA was not added to the mobile phase but to the sample alone. The optimal EDTA amount was determined, and its influence on the separation of the target analyte was investigated. After the feasibility of the “in sample-addition” approach was confirmed, we attempted to improve the previously established sample pretreatment method by varying the conditions for liquid–liquid extraction and solid phase extraction. The developed method was validated using raw chicken meat for recovery evaluation. The “in-sample addition” method afforded highly improved peak shapes without adversely affecting the LC/MS method performance, and the quantification values of enrofloxacin and ciprofloxacin corresponded well with those obtained using the established method. Consequently, the total analysis time for the determination of enrofloxacin and ciprofloxacin in chicken meat CRM could be reduced by simplifying the sample pretreatment procedure. The developed method delivered better reliability compared to the previously established analytical method. The method will be used for stability monitoring of the chicken meat CRM and the development of other meat CRMs for fluoroquinolone analysis and improved food safety applications.

A corn flour certified reference material (KRISS CRM 108-01-011) was developed to ensure accurate and reliable measurements of type B trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol), and deoxynivalenol-3-glucoside. The material was freeze-dried, ground, sieved, and well-mixed. The final produced CRM was packaged at 14 g per unit and stored at -70 °C. The certification was performed using isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). For simultaneous characterization and homogeneity assessments, ten units were randomly selected and analyzed. The among-unit relative standard deviations were below 1 % for all mycotoxins, indicating excellent homogeneity of the CRM. The stability of the CRM was also assessed at various designated temperatures and test periods. The uncertainties of the certified values varied between 2.4 % and 6.2 %, thereby confirming their higher-order metrological quality to provide references for testing laboratories. In case of deoxynivalenol-3-glucoside, an information value was assigned due to the lack of its traceability to the SI units.

Reliable measurements of flavor compounds in fermented food are key for the characterization and standardization of commercial mass production. Among several important flavor compounds, capsaicinoids provide spiciness, one of the most important tastes in traditional Korean kimchi (seasoned and fermented vegetables). In this study, isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS/MS) was developed as a higher-order reference method for the accurate measurement of capsaicinoids to provide reference materials for reliable measurements and standardization in the kimchi industry. The developed method was validated by measuring gravimetrically fortified samples, and its performance parameters were evaluated. The method showed excellent repeatability (n ≥ 5) and reproducibility with ˂ 1% relative standard deviation. The overall measurement uncertainty for individual capsaicinoids was

Many foods contain thiamine as a natural or fortified nutrient. In order to realize accurate measurement of thiamine in various food matrices, analytical methods should be developed on the basis of careful examination of the matrix and the analytes in the matrix. An isotope dilution liquid chromatography–mass spectrometry (ID-LC-MS/MS) method was developed for the analysis of thiamine in various samples such as multivitamin tablets, infant formula, rice, and wheat flour. After using spiked isotope-labeled thiamine HCl (13C4-thiamine HCl) as an internal standard, samples were analyzed by LC/MS in a selected reaction monitoring mode to detect ions at m/z 265 → 122 and m/z 269 → 122 for thiamine and 13C4-thiamine, respectively. To improve the accuracy and precision of this method, the preparation procedure was optimized depending on the chemical form of thiamine present in each sample. Thiamine in multivitamin tablets, infant formula, rice, and wheat flour was analyzed after buffer extraction, acid hydrolysis, and continuous acid and enzyme hydrolyses, respectively. The instrumental analyses were also optimized for individual samples, facilitating excellent repeatability (0.16–0.81%) and reproducibility (0.1–4%). The accuracy of the developed method was verified by comparing the experimental data with the certified values of certified reference materials. Thus, optimization of the preparation procedures and ID-LC-MS/MS method allowed the accurate determination of thiamine in diverse food matrices.

An isotope dilution-gas chromatography/mass spectrometry (ID-GC/MS) method was developed as a candidate reference method for the accurate determination of the amount of fatty acids in infant formula. 13C- or 2H-labeled fatty acids were used as internal standards to correct for recovery and instrument sensitivity during sample preparation and MS measurements, respectively. The developed ID-GC/MS method was validated based on the repeatability and reproducibility of selected fatty acid analyses. For fatty acid measurements in a homogenized infant formula, the repeatability and the reproducibility were

Herein, an isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method was developed as a candidate reference method for the accurate quantitation of hexabromocyclododecane (HBCDD) diastereomers in plastics. The repeatability, reproducibility, and uncertainty results showed that developed ID-LC/MS/MS method is reliable and reproducible. As homogeneous samples, HBCDD-containing extruded high-impact polystyrene (HIPS) pellets were fabricated via an extrusion process. Notably, we detected α-, β-, γ-, δ-, e-, η-, and θ-HBCDDs in the extruded HIPS pellets, and then determined their exact mass fractions using the ID-LC-MS/MS method. The relative contents (average ± standard deviation) of HBCDD diastereomers in HIPS obtained using the phenyl-hexyl column were 67.08 ± 0.41% (α-HBCDD), 19.73 ± 0.37% (β-HBCDD), 11.59 ± 0.16% (γ-HBCDD), and 1.6 ± 0.07% (sum of δ-, e-, η-, and θ-HBCDDs). These values differed significantly from the ones determined for the technical HBCDD mixtures (10.42% α-HBCDD, 5.30% β-HBCDD, 82.13% γ-HBCDD, 2.15% minor HBCDDs) used to fabricate the HIPS pellets and thus demonstrating the HBCDD isomerization during the extrusion. The proportion of minor HBCDDs was smaller than the uncertainty of the total HBCDD and that the sum of α-, β-, and γ-HBCDDs was comparable to the total HBCDD in the investigated samples. Notably, a real-life sample (expanded polystyrene board obtained from a local construction site) also showed a similar HBCDD profile, being rich in α-HBCDD.

We consistently observed a bias in the results for determination of chloramphenicol (CAP) in infant formula by isotope dilution-liquid chromatography/mass spectrometry (ID-LC/MS). Various matrix interferences from infant formula eventually can result in bias during the ID-LC/MS analysis. We tried to optimize LC conditions to minimize matrix effects by separating significant matrix interferences from the analyte and the internal standard, but some level of bias remained. To eliminate the bias due to the matrix effects, we used a standard addition-isotope dilution-liquid chromatography/mass spectrometry (SA-ID-LC/MS) method for CAP analysis. In the SA-ID-LC/MS method, standard addition techniques were combined with IDMS for exact matrix matching while keeping the isotope dilution techniques as a tool for accurate correction of recovery in sample preparation processes. The method provided accurate analytical results for target analyte in the range of 1 µg/kg with a relative expanded uncertainty of 3%.

This study was performed to establish the proper liquid chromatographic conditions for the separation of hexabromocyclododecane (HBCD) diastereomers. Column selectivity towards HBCD diastereomers was evaluated for C18 and phenyl-hexyl stationary phases. First, the baseline separation of the primary HBCDs (α-, β-, and γ-HBCD) was obtained using the ultra-performance liquid chromatography (UPLC) column with C18 stationary phase chosen in most previous studies for HBCD analysis; however, co-elution of δ- and ε-HBCD with the primary HBCD diastereomers was observed. To prevent the interference from δ- and ε-HBCD, we adopted a phenyl-hexyl UPLC column to resolve the HBCD diastereomers. The phenyl-hexyl UPLC column showed significantly different selectivity for the HBCD diastereomers compared with the C18 column, which allowed the clear isolation of δ-HBCD and ε-HBCD from the primary HBCD diastereomers. In addition, by checking the retention times of all HBCD diastereomers using both C18 and phenyl-hexyl columns, we confirmed the presence of δ-, ε-, η-, and θ-HBCDs in two technical HBCD mixtures.

We developed an isotope-dilution gas chromatography/high-resolution mass spectrometry (ID-GC/HRMS) method for the accurate determination of four polycyclic aromatic hydrocarbons (PAHs) in olive oil. The clean-up steps were optimized to sufficiently remove co-extracted oil matrix using the EZ-POP NP dual-layer and NH

An analytical method was developed for the accurate determination of eight polycyclic aromatic hydrocarbons (PAHs) in extruded high-impact polystyrene (HIPS) as a higher-order reference method. Uncleaned HIPS matrix rendered the accurate quantitation impossible and hampered the repeatability of the gas chromatography/mass spectrometry (GC/MS) measurement. This led to a bias in the results and increased the measurement uncertainty. Extracts were sufficiently purified through a two-step process: (i) dissolution and precipitation and (ii) molecularly imprinted polymers-solid phase extraction for clean-up. Co-elution of indeno(1,2,3-cd)pyrene (IP), dibenz(a,h)anthracene (DBahA), and their 13C6-labeled isotopes resulted in a bias in the area ratios of IP/13C6-IP and DBahA/13C6-DBahA, thus increasing the measurement uncertainty. An optimized GC condition using an Rxi-PAH column improved the peak separation of IP and DBahA and their isotopes, thus improving the quality of the measurement. The optimized method was validated using PAH (0.36–0.45 mg/kg)-containing HIPS pellets. The optimized method had excellent repeatability (

Main text The CCQM-K148.a comparison was coordinated by the BIPM on behalf of the CCQM Organic Analysis Working Group for NMIs and DIs which provide measurement services in organic analysis under the CIPM MRA. It was undertaken as a "Track A" comparison within the OAWG strategic plan. CCQM-K148.a demonstrates capabilities for assigning the mass fraction content of a solid organic compound having moderate molecular complexity, where the compound has a molar mass in the range (75 - 500) g/mol and is non-polar (pKow < −2), when present as the primary organic component in a neat organic solid and where the mass fraction content of the primary component in the material is in excess of 950 mg/g. Participants were required to report the mass fraction of Bisphenol A present in one supplied unit of the comparison material. Participants using a mass balance method for the assignment were also required to report their assignments of the impurity components present in the material. Methods used by the seventeen participating NMIs or DIs were predominantly based on either stand-alone mass balance (summation of impurities) or qNMR approaches, or the combination of data obtained using both methods. The results obtained using thermal methods based on freezing-point depression methods were also reported by a limited number of participants. There was excellent agreement between assignments obtained using all three approaches to assign the BPA content. The assignment of the values for the mass fraction content of BPA consistent with the KCRV was achieved by most of the comparison participants with an associated relative standard uncertainty in the assigned value in the range (0.1 - 0.5)%. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

We developed an isotope-dilution gas chromatography/high-resolution mass spectrometry (ID-GC/HRMS) method for the accurate determination of four polycyclic aromatic hydrocarbons (PAHs) in olive oil. The clean-up steps were optimized to sufficiently remove co-extracted oil matrix using the EZ-POP NP dual-layer and NH2 solid-phase extraction (SPE) cartridges. However, the cleaned sample still contained some matrix residues, which caused a bias. When 13C-labeled PAHs were used as the internal standards instead of deuterated PAHs, the recovery results improved in both low- and high-resolution MS conditions. Furthermore, the HRMS analysis facilitated to obtain more accurate results. The accuracy and precision of the optimized ID-GC/HRMS method were validated using PAH-fortified (0.5, 3, and 6 μg/kg) olive oil. The recoveries and relative standard deviations obtained for all the PAHs/levels were 97.5–102% and ~1%, respectively. Measurement uncertainties were generally within 5% (with a 95% confidence level).

The demonstration of competency and equivalence for the assessment of levels of contaminants and nutrients in primary foodstuffs is a priority within the 10-year strategy for the CCQM Organic Analysis WG series of Track A core comparisons. The area of low polarity analytes in high fat foods had not been covered by the OAWG for many years since the key comparison CCQM-K21 p,p'-DDT in fish oil occurring in 2000. Benzo[a]pyrene (BaP) is one of the markers for the occurrence of PAHs in foods, for which maximum residue limits are enforced in many countries. Edible oil and fats are the main source of human PAH intake. BaP may form in edible oils by pyrolytic processes, such as incomplete combustion of organic substances. Worldwide regulatory limits of BaP in edible fats and oils are from 2.0 μg/kg to 10 μg/kg. Comparable and traceable measurement results for BaP in oil are important worldwide. Thus BaP in edible oil was the model system selected to align within the OAWG strategy. 16 NMIs and DIs participated in CCQM-K146. Different methods such as liquid-liquid extraction, GPC and SPE were applied in the sample pre-treatment and HPLC-FLD, HPLC-MS/MS, and GC-MS or GC-MS/MS were applied for detection by the participants. Most participants either used their own CRMs, other NMI's CRMs or pure materials assessed in house to guarantee traceability to SI for the calibrants. One lab was excluded from the KCRV evaluation, as they did not meet the CIPM metrological traceability requirements for their calibrant. Regarding the data evaluation, five labs withdrew their results from the statistical evaluation of the KCRV for technical reasons. In line with the OAWG guidance document for KCRV estimator selection, the Hierarchical Bayes option was selected for the KCRV value, which was determined as 2.74 μg/kg with a standard uncertainty of 0.03 μg/kg. The remaining ten institutes that were included in the calculation of the consensus KCRV all agreed within their standard uncertainties. In general, the majority of CCQM-K146 participants performed very well. Therefore, this Track A Key Comparison directly illustrates the capabilities in determining mass fraction of organic compounds, with molecular mass of 100 g/mol to 500 g/mol, having low polarity pKow < -2, in mass fraction range from 0.1 μg/kg to 1000 μg/kg in a high fat, low protein, low carbohydrate food matrix. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 “Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile”. Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz[a]anthracene (BaA), benzo[a]pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %. Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pKow < −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography. KEY WORDS FOR SEARCH benz[a]anthracene (BaA), benzo[a]pyrene (BaP), gas chromatography(GC), isotope dilution (ID), liquid chromatography (LC), mass spectrometry (MS), naphthalene (Nap), organic calibration solution, polycyclic aromatic hydrocarbon (PAH) Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Infant formula certified reference material (CRM, KRISS CRM 108-02-003) were developed for the analysis of organic nutrients. The CRM is a milk-based infant formula powder, packaged at 14 g per unit. Ten thousand units were prepared and stored at −70 °C. For the certification of each nutrient, ten units were analyzed for simultaneous value-assignment and homogeneity test. Analytical methods used were isotope dilution mass spectrometry (IDMS) based on liquid chromatography mass spectrometer (LC/MS) or gas chromatography mass spectrometer (GC/MS) as higher-order reference methods.13 vitamins, 3 fatty acids, and total cholesterol were certified. The between-unit relative standard deviation of measurement results for each nutrient ranged 0.2% to 2.5%, showing very good homogeneity. The expanded relative uncertainties of the certified values ranged from 1% to 8%, indicating that they have higher-order metrological quality. The values of proximates (proteins, lipids, carbohydrates, water, and ash) were assigned through inter-laboratory comparisons.

Within the Organic Analysis Working Group (OAWG) of the Comité Consultatif pour la Quantitè de Matiére (CCQM), key comparison CCQM-K141 and associated pilot study CCQM-P178 were coordinated by the National Research Council Canada (NRC). This comparison was a Track A key comparison that formed part of the OAWG 10-year strategic plan. The comparison demonstrated capabilities for measuring high-polarity analytes in a high-fat and high-protein matrix. The measurand chosen as the model system was enrofloxacin and sulfadiazine in bovine tissue. Thirteen National Metrology Institutes or Designated Institutes participated in the CCQM-K141, while two National Metrology Institutes participated in CCQM-P178. The bovine muscle tissue study material was derived from a single live animal that was administered with chemical based pharmaceutical agents prior to processing. Therefore, the study material was naturally incurred, providing a true test of extraction procedures relative to more commonly encountered spiked materials. NRC confirmed excellent homogeneity and stability of the material prior to shipping. Three 10 g bottles of freeze dried powdered muscle tissue were supplied. NRC also provided isotopically labelled solutions of the two measurands, 13C6-sulfadiazine and enrofloxacin-d5 (HI Salt), to those interested in using isotope dilution mass spectrometry (IDMS) methodologies. Procurement and purity assignment with appropriate metrological traceability of native calibrants were the responsibility of individual participants. The study required extraction, clean-up, analytical separation, and selective detection of the analytes. The level of agreement was reasonable given the measurands and matrix were new for most laboratories. The KCRV values and their uncertainties at the 95% confidence level of 57.81 ± 2.57 μg/kg for enrofloxacin and 2285 ± 68 μg/kg for sulfadiazine were calculated using the DSL means. While one participant's value was voluntarily excluded from the KCRV calculations for enrofloxacin, all other participants demonstrated equivalence for both measurands. Significant effort was undertaken post-study to identify the major sources of variability between results. In particular, the various extraction conditions used by participants were investigated thoroughly. While there appeared to be a correlation between highly acidic conditions and higher recovery, this was not definitive and could not be confirmed. The form of standards employed (i.e. free base vs salts) and potential differential solubility between forms was also a suspected source of variability. Biases could also have been introduced with the choice of solvents used for standard preparation, with some solvents better able to minimize adsorption of the analytes to glass surfaces. KEY WORDS FOR SEARCH enrofloxacin, sulfadiazine, bovine tissue, incurred, key comparison Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The 2017 CCQM-K147 "Comparison of value-assigned CRMs for niacin (vitamin B3) in milk powder and infant formula matrices" is the first Key Comparison directly testing the chemical measurement services provided to customers by National Metrology Institutes (NMIs) and Designated Institutes (DIs) through certified reference materials (CRMs). CRMs certified for vitamin B3 (as niacin or niacinamide) content in milk powder and infant formula matrices were compared using measurements made on these materials under repeatability conditions. Five NMIs/DIs submitted seven CRMs certified for niacinamide and two CRMs certified for niacin. These materials represent most of the higher-order reference materials available in 2017 for this important nutrimental measurand. Generalized Gauss Markov Regression (GGMR) and Bayesian methods were used to establish the Key Comparison Reference Function (KCRF) relating the CRM certified values to the repeatability measurements. The niacinamide and niacin results for all nine CRMs were deemed equivalent at the 95 % level of confidence and were used to define the KCRF for vitamin B3 (as niacinamide). Monte Carlo methods and Bayesian methods were used to estimate 95 % level-of-confidence coverage intervals for the relative degrees of equivalence of materials, %d ± U95 (%d), and of the participating NMIs/DIs, %D ± U95 (%D). The Bayesian method estimates were selected as the final DoE values. For the niacinamide and niacin materials, all of the %D ± U95(%D) intervals, were within (-10 to 10) % of the consensus results and all of these are statistically equivalent. These results demonstrate that the participating institutions can value-assign CRMs for niacinamide and/or niacin in milk powder and infant formula matrices. KEY WORDS FOR SEARCH Niacin, Niacinamide, milk, infant formula, CRMs Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

XAD-2 resin-based passive air samplers (PAS) were deployed for one year at eight cities in Mongolia, China, and South Korea to investigate the spatial distribution of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and dechlorane plus (DP). PCB levels were highly correlated with population size and density in China and South Korea. In Mongolia, PCB levels were relatively high considering the low population. In the cases of OCPs and DP, a country-specific distribution was observed. The highest levels of HCHs (hexachlorocyclohexane isomers) and DDTs (dichlorodiphenyl trichloroethane isomers) were detected at sites in China, whereas the highest endosulfan and DP levels were measured at South Korean sites. These results strongly reflected the patterns of use of these chemicals. Mirex, an insecticide never registered in Mongolia and South Korea, was detected at all sampling sites; this is likely to have resulted from long-range transport. Nevertheless, OCPs were generally low in Mongolia. This study confirms that PAS results reflect well the past and current usage of POPs in Northeast Asia.

Spatial distribution and seasonal variation of polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) bulk deposition were investigated at four sites at and around an iron and steel making plant in Pohang, South Korea from January 2008 to May 2009. The steel complex site showed the highest average deposition fluxes of 74.0, 2.1, and 41.6 ng m−2 day−1 for ∑tri-decaPCBs (Tri-DecaCBs), ∑12PCBs (dioxin-like PCBs), and ∑8PBDEs (8 PBDE congeners), respectively, indicating the steel complex is an important source of PCBs and PBDEs. The PCB deposition was dominated by Tri-TetraCBs and BDE209 was the most abundant PBDE congener. No clear seasonal variation of PCB and PBDE deposition was observed except at the steel complex site. Precipitation appeared to play an important role in the deposition distribution of PCBs, especially when the lowly chlorinated homologues dominated. In addition, the contribution of DL PCBs (dioxin-like PCBs) to the total TEQ (toxicity equivalent quantity) showed a seasonal variation and should not be neglected in the vicinity of a steel complex.

XAD-2 resin based passive air samplers (PAS) were deployed for three one-year periods at the Korean polar and South Pacific research stations at Ny-Ålesund (2005-2009), King George Island (2005-2007), and Chuuk (2006-2009) to investigate long-range transport, local sources, and temporal trends of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The highest hexachlocyclohexane (HCH) concentration (35.2-78.9 pg·m(-3)) over the entire sampling period was detected at Ny-Ålesund, in the Arctic. α-HCH was the dominant OCP (31.1-67.1 pg·m(-3)), contributing about 50% of the total OCP load. Additionally, a high and consistent α/γ-HCH ratio was observed at Ny-Ålesund. HCHs might reach Arctic sites more easily than other OCPs from surrounding countries through long-range atmospheric transport (LRAT). Interestingly, high levels of the current-use OCP endosulfan-particularly endosulfan-I--were detected at almost all sampling sites, including in Antarctica, ranging 12.2-88.5, 17.7-130, and ND-59.7 pg·m(-3) at King George Island, Ny-Ålesund, and Chuuk, respectively. Specific OCP and PCB patterns, such as low trans/cis-chlordane ratios and a prevalence of lighter PCB congeners, were observed in all three regions (excepting one site at Ny-Ålesund and one site in the South Pacific affected by local sources) during all sampling periods. This indicates that these Polar and remote South Pacific sites are mainly influenced by LRAT. Over the entire sampling period, a decreasing trend of HCHs (α- and γ-HCH) and an increasing trend of endosulfan-I were observed at the Ny-Ålesund sites.

A highly chlorinated flame retardant, Dechlorane Plus (DP), was measured in five fish species collected in 2008 from 22 river sites across South Korea. The sites consisted of 15 urban-industrial areas, three rural-industrial areas, and four rural rivers. Both syn- and anti-DP isomer were consistently detected in all fish samples regardless of sampling sites and fish species. DP has become a widespread environmental pollutant in South Korea. Concentrations of summation operatorDP isomers ranged from 0.61 to 126ngg(-1) lipid, with a mean concentration of 24.5ngg(-1) lipid. The mean summation operatorDP concentrations in the 15 urban sites (36.1+/-35.3ngg(-1) lipid) were approximately 25 times greater than those measured in the rural sites (1.4+/-1.0ngg(-1) lipid). The summation operatorDP concentrations in this study exceeded those determined in fish from the Great Lakes. DP exposure to fish is related to urbanization activity. Specific urban areas could be significant source areas of DP exposure, even in the absence of a local DP manufacturing facility. Concentrations of syn- and anti-DP isomer ranged from 0.17 to 30ngg(-1) lipid and 0.44 to 97ngg(-1) lipid, respectively. The anti-DP isomer was dominant in all samples. However, the mean f(anti) value for urban-industrial samples (0.67+/-0.060) was significantly lower than that of the technical DP standard (f(anti)=0.75; p=0.032). This observation supports that DP isomers exhibit different bioaccumulation behaviors and that syn-DP isomer more easily accumulates in biota samples than anti-DP isomer does.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in human have been studied extensively; however, polychlorinated naphthalenes (PCNs) have been studied less widely. The mean concentrations of PCNs, PCDDs, PCDFs, and PCBs in 61 healthy human volunteers were 2170 pg/g lipid, 452 pg/g lipid, 116 pg/g lipid, and 120 ng/g lipid respectively, and the mean toxic equivalents (TEQs) contributed by PCNs, PCDDs, PCDFs, and PCBs were 5.88, 5.22, 5.48, and 5.33 pg/g lipid, respectively. PCNs contributed to 26.8% of the total TEQs. 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF, PCB126, and hepta-CN-73 accounted for >62% of the total TEQs in the human serum samples. The overall serum PCN homologue profiles of all subjects were dominated by tetra- and penta-CN homologues, and the most predominant individual congener was hepta-CN-73, which contributed 17.5% of the total serum PCN concentration. Enrichment of hepta-CN-73 in the human serum samples might be due to contributors from combustion sources.

The comparison required the assignment of the mass fraction of folic acid present as the main component in the comparison sample. Performance in the comparison is representative of a laboratory's measurement capability for the purity assignment of organic compounds of medium structural complexity [molecular weight range 300–500] and high polarity (pKOW < −2). Methods used by the eighteen participating NMIs or DIs were based on a mass balance (summation of impurities) or qNMR approach, or the combination of data obtained using both methods. The qNMR results tended to give slightly lower values for the content of folic acid, albeit with larger associated uncertainties, compared with the results obtained by mass balance procedures. Possible reasons for this divergence are discussed in the report, without reaching a definitive conclusion as to their origin. The comparison demonstrates that for a structurally complex polar organic compound containing a high water content and presenting a number of additional analytical challenges, the assignment of the mass fraction content property value of the main component can reasonably be achieved with an associated relative standard uncertainty in the assigned value of 0.5% Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

To assess levels and seasonal trends of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in a high-altitude mountain region, a 2.1m snowpack sample was collected from the East Rongbuk Glacier at 6572 ma.s.l. on Mt. Everest in September 2005. This snowpack covered a full year period from the fall of 2004 to the summer of 2005 and reflected the major meteorology of the monsoon and non-monsoon seasons. The most abundant compounds detected in the snow samples were gamma-hexachlorocyclohexane (gamma-HCH) and alpha-HCH with mean concentrations of 123 pg L(-1) and 92 pg L(-1), respectively. This is the first detection of these compounds in recent snow samples from the Himalayas. Backward air trajectory analysis indicated that the Himalayas could be influenced by the major HCH source regions in both India and China. Among the seven marker PCB congeners (PCB 28, 52, 101, 118, 138, 153, and 180) quantified, PCB 28 and PCB 52 were the only dominant PCB congeners detected, with mean concentrations of 17 pg L(-1) and 6 pg L(-1), respectively. In addition, DDT metabolites, p,p'-DDE and p,p'-DDD were detected in some snow samples and mean concentrations of DDTs were 24 pg L(-1). Seasonal differences were observed for alpha- and gamma-HCH concentrations increasing from the non-monsoon season to the monsoon season. Meanwhile, PCB 28 and HCB showed uniform variations with peak concentrations resulting from an effective scavenging by snowfalls between the monsoon and non-monsoon interval. Compared to other high mountain areas, the levels of POPs deposited into the East Rongbuk Glacier were relatively low, resulting from the highest altitude and remoteness from source regions.

Atmospheric monitoring is important for the investigation of source and receptor relationships of persistent organic pollutants (POPs). High volume samplers (HiVol), a kind of active air sampler, have been widely used to collect air samples containing POPs. Recently, passive air samplers (PAS) have been developed, and they have several advantages compared with HiVol. In this paper, we introduced the principle, properties, and applications of several types of PAS. Finally, the results of case studies from our group were presented. Since PAS have no electric pump and are much smaller and cheaper than HiVol, they can be used for various scaled monitoring studies. In Korea, we introduced three types of PAS: (1) semipermeable membrane devices (SPMD), (2) polyurethane foam (PUF), and (3) XAD resin-based PAS. The results of monitoring studies using these samplers suggest that PAS are a useful tool for the investigation on the level and distribution of POPs.

To assess levels and patterns of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in polar regions, XAD-resin based passive air samplers were deployed for one year at the Korean polar research stations at Ny-Alesund, Norway (2005-2006) and King George Island, Antarctica (2004-2005). Backward trajectories suggest that these stations are affected by long-range transport from source regions in Northern Europe and Russia and the southern tip of South America, respectively. Relatively high levels of PCB-11, averaging 60 pg x m(-3), were observed in Antarctica, suggesting an unusual source of PCB-11 to the Southern Hemisphere. Reflecting the hemispheric distribution of global PCB emissions, the average level of sigma205PCB (excluding three mono-CBs and PCB-11) was five times higher in the Arctic (95 pg x m(-3)) than in the Antarctic (19 pg x m(-3)). Levels of sigma9PCB at Ny-Alesund were similarto those reported for other Arctic sites, while levels at King George Island were lower than at other sites on the Antarctic Peninsula but 1 order of magnitude higher than background levels measured at a more remote Antarctic site. Light homologues were predominant in all samples (except for one Arctic sample), consistent with the hypothesis of global fractionation and predictions of long-range transport potential. Dominance of heavy PCBs on the roof of the main building at Ny-Alesund and a concentration gradient with distance from the main building at King George Island strongly indicated the influence of local sources. OCP levels were also influenced by long-range transport but not by local sources. This study highlights the feasibility of using passive air sampling to assess both long-range transport and local pollution in remote regions.

Coplanar polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polybrominated diphenyl ethers (PBDEs) were sampled using polyurethane foam (PUF) disk passive air samplers (PAS) at 19 sites in a heavily industrialized region of South Korea for 6 months (January-July 2006). The levels and spatial distribution of these three chemical groups were investigated to identify potential sources and transport in the study area, which can be divided into five regions: a steel-manufacturing complex, a residential area near the steel complex, a rural area, a semi-industrial area, and a petrochemical-manufacturing complex. Air concentrations (pg x m(-3)) were estimated using an average sampling rate of 3.0 m3 x day(-1) and ranged as follows: coplanar PCBs (0.8-16), PCNs (1.7-35), and PBDEs (3.8-24). The levels of coplanar PCBs and PBDEs were found to be the highest in the steel complex, followed by the petrochemical complex and the semi-industrial area. In addition, a high level of PCNs was measured near a petrochemical-processing plant. However, the residential area near the steel complex and the rural area showed relatively low concentrations of these chemicals, suggesting that the steel and petrochemical industries are probably important sources in the study area, but these potential sources do not strongly influence the surrounding areas.

Polyurethane foam disk passive air samplers (PAS) were deployed in a steel complex, and in residential and semi-rural areas of a city in Southern Korea between January and April 2006. Dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were monitored to investigate the influence of the steel complex on the residential and semi-rural areas. The average levels of ∑12PCB (26.2; 6.1–61.8 pg m−3) and ∑9PBDE (25.2; 9.0–61.6 pg m−3) in the steel complex were higher than those of neighboring areas, indicating that the steel complex is a major source of both chemical groups. No significant difference in the congener patterns for the different areas suggests that the study area is commonly affected by the same sources. Elevated air concentrations at the eastern sites of the city and relatively low concentrations at the residential area close to the steel complex were observed. According to air dispersion modeling, the major wind direction plays a key role in determining this spatial distribution of PCBs and PBDEs. Consequently, the levels of these chemicals at the residential area might not be strongly influenced by the emissions from the steel complex. This study suggests that the combination of passive air sampling and air dispersion modeling is a useful tool for assessing source–receptor relationships of persistent organic pollutants (POPs) on a local scale.

Polyurethane foam-disk passive air samplers (PAS) were deployed in a southern area of Korea for three months. The target compounds were 12 coplanar polychlorinated biphenyls (PCBs). The congener profiles measured in this study were the same as those in ambient air and emission gas from the incinerator. A gradient of the total PCBs in different regions (industrial>residential>rural) was observed, suggesting the industrial complex may be an important source of coplanar PCBs. In general, only gas-phase compounds are mainly sequestrated by PAS. In order to estimate the concentration of particle-phase PCBs, a gas/particle partition model was used. A combined result (gas+particle-phase PCBs) was compared with previous results, indicating that the level of coplanar PCBs in our study area is comparable to those in other urban sites in the world. The validation of this method for estimating the total concentration is required through additional backup studies.

Membrane-enclosed copolymer (MECOPs) samplers containing crystalline copolymers of ethylvinylbenzene-divinylbenzene in polyethylene membranes were used to assess the influence of a steel complex on the level and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in ambient air. MECOPs were deployed at six sites in Pohang, Korea for 37 days (August 9, 2005–September 14, 2005). Fluorene, phenanthrene, anthracene, and fluoranthene were dominant PAHs with the highest contribution of phenanthrene (59%) to the total amount of vapor-phase PAHs. The spatial distribution of total PAHs in the vapor phase ranging from 76 to 1077 ng MECOP−1 and air dispersion modeling suggested that the steel complex was the major PAH source in Pohang. It was revealed that the major wind directions rather than the distance from the steel complex were a significant factor affecting the levels of PAHs at the sampling sites. Finally, we tried to convert MECOP concentrations (ng MECOP−1) to air concentrations (ng m−3) with the modified sampling rates (m3 day−1). This study demonstrates again that passive air samplers are useful tools for spatially resolved and time-integrated monitoring of semivolatile organic compounds (SOCs) in ambient air.

Patulin, a mycotoxin produced by several molds in fruits, has been frequently detected in apple products. Therefore, regulatory bodies have established recommended maximum permitted patulin concentrations for each type of apple product. Although several analytical methods have been adopted to determine patulin in food, quality control of patulin analysis is not easy, as reliable certified reference materials (CRMs) are not available. In this study, as a part of a project for developing CRMs for patulin analysis, we developed isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC/MS/MS) as a higher-order reference method for the accurate value-assignment of CRMs. (13)C7-patulin was used as internal standard. Samples were extracted with ethyl acetate to improve recovery. For further sample cleanup with solid-phase extraction (SPE), the HLB SPE cartridge was chosen after comparing with several other types of SPE cartridges. High-performance liquid chromatography was performed on a multimode column for proper retention and separation of highly polar and water-soluble patulin from sample interferences. Sample extracts were analyzed by LC/MS/MS with electrospray ionization in negative ion mode with selected reaction monitoring of patulin and (13)C7-patulin at m/z 153→m/z 109 and m/z 160→m/z 115, respectively. The validity of the method was tested by measuring gravimetrically fortified samples of various apple products. In addition, the repeatability and the reproducibility of the method were tested to evaluate the performance of the method. The method was shown to provide accurate measurements in the 3-40 μg/kg range with a relative expanded uncertainty of around 1%.

In 2009 and 2010, 720 serum samples were collected from non-occupationally exposed study participants at four Korean locations and monitored for the presence of 27 polybrominated diphenyl ether (PBDE) congeners. The median concentrations of Σ(27)PBDEs (the sum of 27 congeners) and Σ(3-7)PBDEs (the sum of tri- to hepta-BDE congeners) were 6.04 and 4.97 ng/g lipid, respectively. The most abundant congener detected in serum samples was BDE-153, followed by BDE-47 and BDE-99. The median value of Σ(3-7)PBDEs was similar to the median values observed in Asia and Europe, but much lower than that observed in North America. Some significant differences, based on geographic region and sex, were observed. We also observed a positive increase of BDE-153 with regard to age. In addition, we estimated the daily exposure to PBDEs from previously published reports of PBDE concentrations in food and dust, and determined the individual contributions of a variety of sources.

An IRA-743 resin bulk sampler was validated to monitor long-term bulk deposition of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Six consecutive sampling campaigns (2008–2009) were conducted at four sites around steel complexes in Pohang, South Korea to investigate spatial and seasonal variations of PCDD/F bulk deposition. The bulk deposition within the steel complex showed the highest ∑4–8PCDD/F (Tetra-Octa) fluxes, ranging from 204 to 608 (mean: 352) pg m−2 d−1, indicating steel complexes were major sources of PCDD/Fs. The homologue profiles were dominated with lower chlorinated PCDFs. Furthermore, the prevailing winds were confirmed to influence the spatial distribution of PCDD/F deposition. There were apparent seasonal variations of the bulk deposition at each site, and seasonal homologue patterns of PCDD/Fs were clearly observed. According to the passive air sampling, however, no significant seasonal change of ambient air concentrations of PCDD/Fs was observed. Therefore, it was concluded that the seasonal variations of deposition fluxes of PCDD/Fs probably resulted from temperature-dependent gas/particle partitioning.

Four consecutive passive air samplings (September 2006-July 2007) were conducted at 15 sites around an iron and steel making plant in Pohang, Korea to investigate the spatial and seasonal distributions of polychlorinated biphenyls (PCBs) and ultimately the source-receptor relationships. Annual mean values of Sigma(8)PCBs (IUPAC number 8, 28, 52, 101, 118, 138, 153, 180) were in the range of 15.1-166 pg/m(3) with an average of 53.0 pg/m(3). The spatial distribution of PCBs for each sampling period clearly suggests that the steel complex is a major source of PCBs in this area, and the prevailing winds facilitated the atmospheric transport and dispersion of PCBs from the steel complex to the surrounding areas. Seasonal patterns of PCBs were observed clearly, which were influenced by meteorological conditions; the highest levels of PCBs were observed with the highest average air temperature, and the influence of rainfall (i.e., wet scavenging) was also observed. In addition, PCB 11, a non-Aroclor congener, was detected in high concentrations at all sites, implying that the sources of PCB 11 are both unique and ubiquitous. This study confirms that passive air sampling is a useful tool to obtain seasonal and spatial distributions of time-averaged POPs data at a local scale.

This study was conducted to examine PBDE exposure in Koreans, with a special focus on incinerator workers due to their potential for occupational exposure to PBDEs. A total of 92 blood samples from 30 incinerator workers, 51 nearby residents and 11 controls were analyzed. The mean total PBDE concentration calculated from the 13 most concentrated congeners for all samples was 16.84 ± 7.48 ng/g lipid, which was somewhat higher concentration than in other countries except North America and Canada. The PBDE levels and congener profiles detected in incinerator workers were not distinctly different from those found in the general population. In all groups tested, BDE-47 was dominant (mean contribution = 32.5%) followed by BDE-153 (23.6%) and relatively high portions of BDE-183 (16.5%) were found. No strong trend was observed between PBDE levels and a number of key biological factors examined in this study, however, weak correlations were observed in PBDE levels measured against dietary habits, particularly in fish consumption frequency and gender. Overall, our data suggest that the occupational exposure of incinerator workers to PBDEs can be considered minor, while other lifestyle factors can have a greater contribution to PBDE exposure.