Influence of water and food consumption on inadvertent antibiotics intake among general population

Antibiotic entry into the water environment has been of growing concern. However, few investigations have been performed to examine the potential for indirect human exposure to environmental antibiotic residues. We evaluated the contribution of drinking water and major food consumption to inadvertent intake of antibiotic residues among general human population in Korea. We estimated daily human intake of six antibiotics, i.e., sulfamethazine (SMZ), sulfamethoxazole (SMX), sulfathiazole (STZ), trimethoprim (TMP), enrofloxacin (EFX), and roxithromycin (RTM), by measuring the concentrations of the antibiotics and their major metabolites in urine from general population in Korea (n=541). In addition, we measured antibiotics from source water of drinking water as well as in tap water samples, and surveyed water consumption rates among the study population. To assess the contribution of dietary factor, we also surveyed consumption pattern for several major foods which are suspected of antibiotics residue. SMZ, Sulfamethazine-N4-acetyl (SMZ-N4), TMP, EFX, ciprofloxacin (CFX), and RTM were detected up to 448, 6210, 11,900, 6970, 32,400, and 151 pg/ml in the urine samples, respectively. Estimates of daily intake of major antibiotics did not appear to be related with consumption of drinking water although antibiotics were frequently detected in source waters (10-67 ng/l). Consumption of several foods correlated significantly with urinary excretion of several antibiotics. Daily intake estimates of EFX and CFX were associated with consumption of beef, pork, and dairy products; those of SMZ and TMP associated with pork and dairy products; and that of TMP related with raw fish. Daily antibiotics intake estimates however did not exceed the acceptable daily intake levels.     

Analysis of sulfonamides,fluoroquinolones, tetracyclines,triphenylmethane dyes and other veterinary drug residues in cultured and wild seafood sold in Montreal,Canada

Freshwater and marine seafood products purchased in Montreal, Canada, were screened for diverse veterinary drug residues including sulfonamides and potentiators, macrolides, lincosamides, nitrofurans, nitroimidazoles, amphenicols, quinolones and fluoroquinolones, one triphenylmethane dye and its leuco-metabolite, and tetracyclines. QuEChERS extraction ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was validated in three model matrices (fatty fish, lean fish, and shrimp edible meat). Method detection limits were in the range of 0.002–3 μg/kg, and the accuracy of matrix-matched extracted calibrants was generally within acceptance criteria. The aquaculture or wild-caught samples of pangasius (basa), cod, salmon, sole, tilapia, trout, white shrimp and giant tiger prawn originated from Canada, China, India, Southeast Asia (Indonesia, Thailand, Vietnam), and other regions worldwide. Overall, 38 % of the tested fish and shrimp samples had detectable residues of at least one veterinary drug or metabolite, and 25 % were not compliant to Canadian guidelines. Leucomalachite green was detected across various sample types (detection frequency: 13 %; maximum: 0.9 μg/kg). Other detected compounds (2–11 % of samples) included tetracycline (maximum: 36 μg/kg), 4-epi-oxytetracycline (18 μg/kg), oxytetracycline (13 μg/kg), metronidazole (13 μg/kg), sulfamethazine (4.8 μg/kg), sulfamethoxazole (4.2 μg/kg), trimethoprim (0.59 μg/kg), florfenicol (0.27 μg/kg), flumequine (0.21 μg/kg), enrofloxacin (1.6 μg/kg), and ofloxacin (0.52 μg/kg).     

Ionic liquid functionalized zinc oxide nanorods for solid-phase microextraction of aflatoxins in food products

Aflatoxins (AFs) in food and agricultural products pose serious health hazards to consumers. As a result, exports are restricted and farmers lose much needed income. One major challenge faced in controlling AFs in developing countries in particular is lack of simple and cost-effective methods of analysis. To address this problem, a solid-phase microextraction (SPME) technique was developed based on 1-hexyl-3-methylimidazolium hexafluorophosphate functionalized zinc oxide nanorods for the extraction of AFB1, AFB2, AFG1 and AFG2 in food products prior to HPLC analysis. The SPME was performed using 10 mg of the adsorbent at pH 7 and vortexing for 1 min at 500 rpm, and desorbed by sonication for 2 min in 1 mL acetonitrile. The technique showed excellent linearity (correlation coefficients, ≥0.997). LOD and LOQ were determined respectively to be 0.07 and 0.73 μg/kg for AFB1, 0.01 and 0.12 μg/kg for AFB2, 0.04 and 0.44 μg/kg for AFG1 and 0.02 and 0.18 μg/kg for AFG2. The intra- and inter-day relative standard deviations were in the ranges of 3.9–4.7% and 6.9–8.4%, respectively. The acquired recovery of blank samples of the pepper and groundnut samples spiked with mixed analytes at 5 and 10 μg/kg spiking levels were in the range of 88.6–99.8%. The SPME was employed for the analysis of the considered analytes from real chili pepper and processed groundnut samples. Overall, the technique is easy, fast, cost-effective and environmentally friendly and can be used for the analysis of AFs in various food and agricultural products.     

厦门市121份市售食品中苯并(a)芘污染状况

目的 了解厦门市市售食品中苯并(a)芘(BaP)的污染状况.方法 采用导数-恒能量同步荧光光谱技术,以自行研制的BaP快速检测仪对厦门市流通市场上采集的121份食品中BaP的含量进行检测.结果 检测发现在121份样品中有84.3%检出BaP,含量为0.17～59.00μg/kg,其中含量超过5.00μg/kg的食品有60份,占49.6%,主要集中在烧烤小食品、加工的肉制品和水产品,含量范围分别是1.44μ54.10μg/kg、0.17～59.00μg/kg、2.79～36.80μg/kg.在34份采自路边流动摊点的食品中,BaP含量为1.78～49.60μg/kg,其中超过5.00 μg/kg有30份,达88.2%.结论所采集121份厦门市售食品中BaP的污染较为严重.     

Application of deep eutectic solvent as a disperser in reversed-phase dispersive liquid-liquid microextraction for the extraction of Cd(II) and Zn(II) ions from oil samples

A new, sensitive, and safe pretreatment method for the analysis of Cd(II) and Zn(II) ions in oil samples prior to flame atomic absorption spectrometry was developed. For the first time, a deep eutectic solvent is used as a disperser in reversed-phase dispersive liquid-liquid microextraction procedure. For this purpose, a deep eutectic solvent with low viscosity and miscible with both aqueous and organic phases is prepared by mixing glycolic acid and mandelic acid at a molar ratio of 2:1. The variables involved in this process were studied to provide high enrichment factors. Under optimized conditions, the linear ranges of calibration curves for Cd(II) and Zn(II) ions were obtained 0.30−20 and 0.50−30 μg L⁻¹, respectively. The obtained detection limits and enrichment factors were 0.12 and 0.18 μg L⁻¹; and 32.7 and 32.2 for Cd(II) and Zn(II), respectively. Repeatability of the proposed method, expressed as relative standard deviation, ranged from 2.7 to 4.1 % (n = 6, C = 1 μg L⁻¹ of each cation). Finally, the proposed method was successfully applied for the determination of Cd(II) and Zn(II) concentrations in various oil samples.     

2007-2008年中国谷物中隐蔽型脱氧雪腐镰刀菌烯醇及多组分真菌毒素污染状况

目的 了解我国部分地区谷物中隐蔽型脱氧雪腐镰刀菌烯醇(DON-3-G)及多组分真菌毒素污染状况.方法 2007-2008年在河南、河北、广西、安徽、四川、重庆和江苏7个省(市、自治区)采集玉米、小麦等样品共计446份,用超高效液相色谱-串联质谱(UPLC-MS/MS)方法检测样品中DON-3-G及多组分真菌毒素[包括脱氧雪腐镰刀菌烯醇(DON)、玉米赤霉烯酮(ZEN)、雪腐镰刀菌烯醇(NIV)等]的污染状况.结果 小麦、玉米中污染的主要真菌毒素为DON及其衍生物和ZEN.88%(169/192)的小麦样品中检出DON(1.5～590.7μg/kg;中位数:30.8μg/kg);22.9%(44/192)的小麦样品中ZEN阳性(1.7～3425.0 μg/kg;中位数:8.0μg/kg),其中有6份样品中ZEN含量超过我国规定的限量标准(60μg/kg).50.5%(103/204)的玉米样品中DON阳性(1.6～4374.4 μg/kg;中位数:94.9μg/kg),7份样品中DON含量超过我国规定的限量标准(1000μg/kg);41.7%(85/204)的玉米样品中ZEN阳性(1.6～4808.7 μg/kg;中位数:48.5μg/kg),其中有37份超过我国规定的限量标准(60 μg/kg).首次在国产小麦和玉米中检出DON-3-G,小麦、玉米样品中DON-3-G中位数分别为21.4μg/kg和34.6 μg/kg,小麦中DON-3-G均高于3-乙酰化DON(3-A-DON,中位数:4.1μg/kg)和15-乙酰化DON(15-A-DON,中位数:3.1μg/kg)(t值分别为5.111和5.966,P值均<0.01);玉米中15-A-DON(中位数:48.6μg/kg)高于3-A-DON(中位数:6.8 μg/kg)(t=-3.579,P<0.01).玉米中DON、DON-3-G、3-A-DON、15-A-DON和ZEN的污染水平均高于小麦(Z值分别为-3.492、-1.960、-2.467、-8.711和-6.272,P值均<0.05),而NIV在小麦中水平(中位数:29.0μg/kg)高于玉米(中位数:18.2μg/kg)(Z=-2.086,P<0.05).结论 我国部分地区小麦、玉米被多组分真菌毒素污染,以DON检出率最高;玉米中受DON、DON-3-G、3-A-DON、15-A-DON和ZEN的污染比小麦重.

Abstract：

Objective To elucidate the natural occurrence of masked deoxynivalenol (DON-3-G)and other multi-mycotoxins in cereals from parts of China. Methods A total of 446 corn and wheat samples harvested in 2007 and 2008 collected from Henan, Hebei, Guangxi, Anhui, Sichuan, Chongqing and Jiangsu provinces were analyzed for DON-3-G and other multi-mycotoxins (including deoxynivalenol (DON),zearalenone(ZEN), nivalenol (NIV), et al) by UPLC-MS/MS. Results Corn and wheat samples were mainly contaminated by DON and its derivatives as well as ZEN. 88% (169/192) of wheat samples were positive for DON (range: 1.5-590. 7 μg/kg; median: 30. 8 μg/kg) ;22. 9% (44/192) of wheat samples were contaminated with ZEN (range: 1. 7-3425.0 μg/kg; median: 8.0 μg/kg) and six samples contained ZEN concentration higher than the ZEN tolerance limit of 60 μg/kg. DON was detected in 50. 5% (103/204) corn samples (range: 1.6-4374. 4 μg/kg; median: 94. 9 μg/kg); Seven samples contained DON exceeding the tolerance limit of 1000 μg/kg for DON. Additionally, ZEN was found in 41.7% (85/204) corn samples with the concentration between 1.6 μg/kg and 4808.7 μg/kg (median:48.5 μg/kg)and there were 37 corn samples with ZEN level in the excess of tolerance limit for ZEN (60 μg/kg). DON-3-G was detected in corn and wheat samples for the first time in China with the median level of 21.4 μg/kg and 34. 6 μg/kg for wheat and corn,respectively. Wheat was more heavily contaminated with DON-3-G than both 3-aeetly-DON (3-A-DON,median:4. 1μg/kg) and 15-acetly-DON (15-A-DON,median :3. 1 μg/kg)(t values were 5. 111 and 5. 966, respectively,both P values <0. 01). While,the level of 15-A-DON (median: 48. 6 μg/kg) in corn was higher than 3-A-DON (median: 6. 8 μg/kg) (t =-3. 579,P < 0. 01). The concentration of DON, DON-3-G, 3-A-DON, 15-A-DON and ZEN in corn were higher than that in wheat (Z values were-3. 492,-1. 960,-2. 467,-8. 711 and-6. 272, respectively,all P values < 0. 05). Wheat(median: 29. 0 μ.g/kg) contained higher NIV in comparison with corn(median:18.2 μg/kg,Z=-2.086,P<0.05). Conclusion Wheat and corn samples from parts of China were contaminated with multi-mycotoxins and DON was the predominant;in comparison of wheat,corn was more heavily contaminated with DON, DON-3-G,3-A-DON, 15-A-DON and ZEN.     

Zirconium nanoparticles based ligandless dispersive solid phase extraction for the determination of antimony in bergamot and mint tea samples by slotted quartz tube-flame atomic absorption spectrophotometry

A sensitive and effective analytical method was developed to preconcentrate antimony from the bergamot and mint tea samples for its determination at trace levels by slotted quartz tube-flame atomic absorption spectrophotometry (SQT-FAAS) system. The developed method was based on vortex assisted ligandless dispersive solid phase extraction (VA-LDSPE) using zirconium nanoparticles (Zr-NPs) as sorbent material for the adsorption of the target analyte. All variables involved in the DSPE method (pH value, nanoparticle amount, mixing and eluent type/volume) were optimized to boost the absorbance signal of antimony. Using the optimal parameters, the method provided satisfactory detection and quantification limits of 8.0 and 26.8 μg L⁻¹, respectively. A 180 folds enrichment factor was achieved by the developed method when compared with the detection power of the FAAS. Linear range of the proposed method was found to be 30–250 μg L⁻¹, with a coefficient of determination value of 0.9992. The established Zr-NPs-VA-LDSPE-SQT-FAAS method was successfully implemented to bergamot tea samples in order to check accuracy and applicability. The obtained recovery values ranged between 93–102%, and this demonstrated that the complex matrices tested did not affect the accuracy of quantifying antimony.     

2010年杭州市售发酵性食品中氨基甲酸乙酯调查与分析

目的 调查2010年杭州市售发酵性食品中氨基甲酸乙酯含量.方法 2010年在杭州大、中、小型3家超市采集237份发酵性食品,包括黄酒、白酒、葡萄酒、啤酒、料酒、酱油、食醋、腐乳等8类食品,采用D5-氨基甲酸乙酯核素稀释技术,硅藻土固相萃取净化样品,然后用气相色谱-质谱法测定样品中氨基甲酸乙酯.结果 237份发酵性食品中氨基甲酸乙酯检出率为100%,含量范围为2.0 ~515.0 μg/kg,氨基甲酸乙酯含量平均值(中位数)从高到低依次为红腐乳[182.2 μg/kg(161.2 μg/kg )]、黄酒[159.6 μg/kg(121.0 μg/kg)]、料酒[86.8 μg/kg(95.6 μg/kg)]、白酒[72.0 μg/kg(60.5 μg/kg )]、酱油[47.2 μg/kg(40.7 μg/kg)]、食醋[26.7 μg/kg(31.8 μg/kg )]、葡萄酒[15.7 μg/kg(16.8 μg/kg )]、啤酒[2.2 μg/kg(2.3 μg/kg)].结论 2010年杭州市发酵性食品中均存在氨基甲酸乙酯,尤以红腐乳、黄酒中氨基甲酸乙酯含量为高.

Abstract：

Objective To observe the ethyl carbamate concentrations in different commercial fermented foods in Hangzhou in 2010.Methods In 2010,237 commercial fermented food samples of eight categories,including yellow wine,white spirit,wine,beer,cooking wine,sauce,vinegar and fermented bean curd,were purchased from 3 different size markets respectively in Hangzhou.The ethyl carbamate was measured by gas chromatography-mass spectrometry in selection ion mode,after the samples were coupled with D5-ethyl carbamate,and purified by diatomite solid phase extraction column.Results The results showed that ethyl carbamate was detected in all samples analyzed (100%) with the range from 2.0 μg/kg to 515.0 μg/kg.The ethyl carbamate average(median)levels in 8 food catergories were descending with fermented red bean curd (182.2 μg/kg (161.2 μg/kg)),yellow wine (159.6 μg/kg (121.0 μg/kg)),cooking wine (86.8 μg/kg (95.6 μg/kg)),white spirit (72.0 μg/kg (60.5 μg/kg)),soy sauce (47.2 μg/kg(40.7μg/kg)),vinegar (26.7 μg/kg (31.8 μg/kg)),wine (15.7 μg/kg (16.8 μg/kg)) and beer (2.2 μg/kg (2.3 μg/kg)).Conclusion The ethyl carbamate was detected in all fermented foods in Hangzhou in 2010,and the levels of ethyl carbamate in red bean curd and yellow wine were higher than others.     

烟台市发酵性调料中氨基甲酸乙酯污染状况调查

目的:探讨烟台市发酵调料中氨基甲酸乙酯(ethyl carbamate,EC)污染状况,对本地区发酵性调料的食品安全性进行调查与评估。方法:随机选取2011年烟台市超市及食品供销部的158份发酵食品,应用基质固相分散萃取(MSPD)技术GC/MS定量分析各类发酵调料食品中EC的含量。结果:(1)158份发酵性调料食品中阳性样品数为117份,阳性率为74.05%,其中黄酒及料酒中EC阳性率最高,平均含量分别为73.1μg/kg、66.4μg/kg,酱油和食醋中EC的含量相对较低,平均含量为40.3μg/kg、29.1μg/kg,腐乳EC平均含量为27.5μg/kg;(2)EC阳性腐乳样品数为36份,其中红腐乳19份,白腐乳17份,两组间EC含量水平无显著差异性。结论:烟台市发酵调料食品中普遍存在EC,其中黄酒及料酒中EC阳性率最高,且EC含量最高值为100.2 mg/L,发酵调料的食品安全问题应进一步加强监管、严格调控。     

Levels of polycyclic aromatic hydrocarbons in milk and milk powder samples and their likely risk assessment in Iranian population

An MSPE/GC–MS method was used for the measuring of 16 PAHs and assessing of the effect of different factors on PAHs concentrations among different types of dairy products. Moreover, the probabilistic health risk assessment due to ingestion of PAHs by the consumption of milk and milk powder was evaluated. The limit of detection (LOD) and limit of quantitation LOQ were ranged between 0.040-0.075 and 0.121-0.227 μg/kg, respectively. The highest mean of total PAHs was noted in milk powdered (2.28 ± 0.39 μg/kg), while the lowest content was observed in pasteurized milk (0.87 ± 0.18 μg/kg). Except for a few samples of milk powder, the PAHs contents of the other samples was lower than standard limits while the concentration of BaP was lower than of standard levels proposed by EU (0.02-0.06 μg/kg). Considering season effect, the samples in winter had the highest level of PAHs. The percentile 95% actual THQ was the 3.64E-04 value that was lower than 1 value. Hence, the consumers are not at considerable non-carcinogenic health risk while the actual ILCR was 3.53E-03 as higher than 1E-04. Therefore, consumers are at considerable carcinogenic risk. Generally speaking, approaching the control plans for a decrease in the concentration of PAHs in dairy products in order to control carcinogenic health risk is crucial.     

食品中非法添加和滥用化学染料的分析研究

建立了食品中碱性黄、碱性嫩黄、碱性橙II、酸性橙II、罗丹明B、对位红、苏丹类1-4号11种有机染料的高效液相色谱分析方法。在0.2-10μg/mL的浓度范围内线性相关系数良好,相关系数范围为0.9996-0.9999,检测限0.05μg/mL。该方法涉及的化学试剂少,操作简便,结果准确。对阳性样品进一步采用液质联用技术确证。     

Characterization of Salmonella enterica isolates from turkeys in commercial processing plants for resistance to antibiotics, disinfectants, and a growth promoter

Salmonella enterica isolates from turkeys in two commercial processing plants (1 and 2) were characterized for susceptibility to antibiotics, disinfectants, and the organoarsenical growth promoter, 4-hydroxy-3-nitrophenylarsonic acid (3-NHPAA, roxarsone), and it's metabolites, NaAsO(2) (As(III)) and Na(2)HAsO(4) ? 7H(2)O (As(V)). The 130 Salmonella serovars tested demonstrated a low incidence of resistance to the antibiotics gentamicin (GEN), kanamycin (KAN), sulfamethoxazole (SMX), streptomycin (STR), and tetracycline (TET). Isolates resistant to antibiotics were most often multidrug resistant. Serovars Hadar and Typhimurium were resistant to KAN, STR, and TET and GEN, SMX, and STR, respectively. All isolated Salmonella serovars were resistant to the disinfectant chlorhexidine with minimum inhibitory concentrations (MICs; 1-8?μg/mL), and they were susceptible to triclosan and benzalkonium chloride. The didecyldimethylammonium chloride component was the most active ammonium chloride tested. No cross-resistance was observed between antibiotics and disinfectants. The MICs for 3-NHPAA (4096?μg/mL) were consistent between processing Plant 1 and Plant 2, but MICs for the 3-NHPAA metabolites (As(III) and As(V)) were higher in Plant 1 than in Plant 2. In Plant 1, 76% of the isolates had MICs >256?μg/mL for As(III) and 92% of the isolates had MICs >1024?μg/mL for As(V). In Plant 2, all of the isolates had MICs ≤256?μg/mL for As(III) and 90% of the isolates had MICs ≤1024?μg/mL for As(V). Only 4 Salmonella serovars were isolated from Plant 1, but 10 serovars were isolated from Plant 2. S. enterica serovar Derby from Plant 1 was highly resistant to As(III) and As(V) with MICs >1024 and >8192?μg/mL, respectively, suggesting previous exposure to high arsenic metabolite concentrations. These levels may have been high enough to kill other Salmonella serovars, thus possibly explaining the lack of serovar diversity observed in Plant 1. The application of a growth promoter may affect the serovar diversity in treated birds.     

提高外环境水体中霍乱弧菌检出率的方法研究

目的 了解外环境水体标本在庆大霉素平板上的菌群分布及优势菌的耐药谱,研究提高霍乱弧菌检出率的方法.方法 采集闽江水体用庆大平板分离培养,用K-B法检测20种抗菌药物对优势菌的敏感性;选择痢特灵,将不含霍乱弧菌的水样一代以及二代增菌液作为稀释液,对不同型别的霍乱弧菌进行倍比稀释,观察其在庆大平皿上的生长情况.结果 330份标本共检出优势菌151株,其中79.5％为气单胞菌.151株优势菌对阿米卡星、诺氟沙星、环丙沙星等9种抗菌素的敏感率达80％以上.在一代增菌液为稀释介质的生长试验中,当痢特灵的浓度≥4μg/mL时,不同型别的霍乱弧菌能检测到的最低菌浓度均有一定的提高;而以二代增菌液为稀释介质时,痢特灵的浓度需≥8μg/mL或16 μg/mL.结论 在庆大霉素琼脂平皿中加入不同浓度的痢特灵,在一定程度上能提高霍乱弧菌的检出率.     

Gas chromatography with mass spectrometry detection and characterization of 27 sterols in two truffle (Tuber) species

Fungal sterols (mycosterols) were investigated in seven samples of both Tuber aestivum and Tuber borchii truffles from Italy, Spain and Romania by means of gas chromatography with mass spectrometry (GC/MS). Sterol contents varied from 130 to 590 mg/100 g dry weight (T. borchii) and 110−420 mg/100 g dry weight (T. aestivum). The sterol pattern of both truffle species was dominated by ergosterol (60–85 %) and brassicasterol (4–33 %). In addition, 25 minor sterols were detected with 27 (n = 3), 28 (n = 17), 29 (n = 3), 30 (n = 2) and 31 (n = 2) carbon atoms (Limit of detection: 2 μg/100 g dry weight). Fourteen minor sterols were described for the first time in Tuber species. Ten minor compounds were detected in all samples in varying abundances, while the others were (i) exclusively detected in all samples of one species (T. borchii: fecosterol, ergosta-8-enol; T. aestivum: 24-methyleneergosta-5,22,24-trienol) or (ii) varied strongly in abundance (≥90 %). Variations in main and selected minor sterols could be partly related to different harvest times. In addition, differences in fungisterol and ergosta-5,7-dienol between the both species were attributed to different pathways in fungal sterol biosynthesis (oneway ANOVA p ≤ 0.01). Our study indicates that sterol pattern analysis could be used to differentiate different Tuber species.     

Aluminium in infant foods: Total content,effect of in vitro digestion on bioaccessible fraction and preliminary exposure assessment

The objective of this study was to determine the total concentration and bioaccessible fraction of aluminium (Al) in 95 different baby food samples and estimate the exposure assessment. Total Al content was determined following oxidative microwave digestion by inductively coupled plasma optical emission spectrometry. An in vitro digestionmethod was optimized to evaluate the bioaccessible fraction. Total concentration and bioaccessibility varied according to the sample composition (saltypurees, fruit purees, infant drinks and petitsuisse). Petit suisse, soy-based drink and salty puree samples presented the highest total Al concentrations of 4170 μg kg⁻¹, 2860 μg kg⁻¹ and 2760 μg kg⁻¹, respectively. Bioaccessiblefraction varied from 0.5%–48% according to their composition.Exposure to Al was estimated and compared with the tolerable weekly intakes currently established. The results showed that the consumption of 3 portions/day of soy-based drink along the week could represent a concern.     

Assessing sialic acid content in food by hydrophilic chromatography-high performance liquid chromatography

We have established a novel hydrophilic chromatography (HILIC)-high performance liquid chromatography (HPLC) method to assess sialic acid content in food products. Single-factor and response surface methodologies (RSM) were used to systematically optimize the hydrolysis conditions of the food samples to extract the maximum amount of sialic acid. Chromatographic conditions were also adjusted. In foods containing sialic acid, we observed a strong linear relationship between sialic acid and peak area, ranging from 5 to 100 μg/mL (R² = 0.9998). The lowest detectable sialic acid concentration (RSN = 3) was 0.2 μg mL⁻¹, and the method detection limit was 0.02mg kg⁻¹. Sample recovery ranged from 95.85% to 99.78%, with an RSD of 1.46% (n = 6). Thus, the described method can be applied to the study of sialic acid content in foods.     

Separation and determination of alkylamides from prickly ash powder using molecularly imprinting technique

In this work, a molecularly imprinted polymer solid phase extraction method was developed to extract Zanthoxylum alkylamides from prickly ash. Surface molecularly imprinted polymers (SMIP) were prepared using the molecular structural analogs of sanshool as a dummy template molecule and acylated silica as backbone. The structural characteristics of the polymers were determined by Fourier-transform infrared spectroscopy and scanning electron microscopy. Dynamic adsorption and isothermal adsorption were investigated. SMIP was used to prepare a molecularly imprinted solid-phase extraction column (SPEC) for the extraction of Zanthoxylum alkylamides from prickly ash powder, followed by high performance liquid chromatography (HPLC) determination. Through separation by SMIP-SPEC, the purity of alkylamides in prickly ash extracts increased from 27.26%–93.58 %. Good linearity for alkylamides standard solution was obtained in the range of 1.0–800.0 μg/mL, and low detection and quantification limits were 0.044 and 0.147 μg/mL, respectively. The method recoveries at four concentration levels of alkylamides were found within 90.3−97.1 % with relative standard deviations (RSDs) of 2.5%–5.9%. These indicate the good recognition ability and affinity to Zanthoxylum alkylamides of SMIP and the novelty of the method for the extraction of alkylamides. The method described could be used for the enrichment of alkylamides and rapid detection.     

新兵人群A群流行性脑脊髓膜炎抗体的血清流行病学调查

目的 了解入伍新兵人群中流行性脑脊髓膜炎(流脑)IgG抗体的流行分布情况,为今后预防提供科学依据.方法 采用血清流行病学调查方法,用ELISA法对北京军区近4年来自7个省市的360名入伍新兵的血清进行流脑IgG抗体检测,统计分析其阳性率.结果 各年间入伍新兵血清流脑IgG抗体历年无显著变化,阳性率在66.67%～96.67%,平均83.33%;抗体含量在6.23～26.47μg/mL,平均12.42μg/mL,地区间差异有统计学意义,湖北省(96.67%)、山东省(91.43%)和北京市(88.00%)较高,河南省(66.67%)和陕西省(72.50%)较低;入伍前工作与否人群,抗体阳性检出率差异无统计学意义(χ2=0.12,P>0.05).结论 入伍新兵人群中流脑IgG抗体阳性率为66.67%～96.67%,抗体含量在6.23～26.47 μg/mL,并有地区差异,所以在新兵入伍期间应采取预防接种、健康教育等有效预防措施.     

石墨炉原子吸收分光光度法测定食品中镉

目的:研究石墨炉原子吸收分光光度法测定食品中镉含量的实验条件及影响因素。方法:采用500℃干灰化法和硝酸、高氯酸混合酸消化法处理样品,以(NH4)3PO4做基体改进剂,采用石墨炉原子吸收分光光度法测定食品中镉含量。结果:方法最低检出限、批内相对标准偏差、批间相对标准偏差和回收率分别为0.014μg/L、2.09%～3.33%、5.79%和92.0%～106%;标准曲线线性范围0.50～4.00μg/L,回归方程Y=0.0506X+0.00999,相关系数r=0.9990。测定国家标准物质(GBW07604,镉标准值:0.32±0.07μg/g)中镉的含量为0.311μg/g,相对误差2.81%。结论:该方法具有较高的灵敏度、准确度和精密度,适用于食品中微量镉的测定。     

Salting-out homogeneous liquid-liquid microextraction for the spectrophotometric determination of iodate in food grade salt

A simple and rapid method has been reported for the determination of iodate in food grade salt samples where iodate has been used for the oxidation of phenylhydrazine to phenyldiazonium ion which then couples with 2-naphthol or with 8-hydroxyquinoline to produce orange red azo dye. The dye was extracted with microliter volume of 2-propanol, when the phase separation occurred by addition of ammonium sulphate, a process called salting out homogeneous liquid liquid microextraction (SH-LLME), and analysed spectrophotometrically. Relative efficiencies of both the coupling reagents were compared for iodate determination, when both coupling agents, 8-hydroxyquinoline and 2-naphthol, produced relatively comparable results. The method has been optimized for the reaction time, and type of extracting solvent and salt for phase separation. A linear calibration curve was obtained for 0.08−10 mg L⁻¹ of iodate with correlation coefficient of 0.998 and limit of detection of 16 μg L⁻¹. Food grade salt samples have been analyzed with adequate recovery in spiking experiments, being, 86.2–114.6 (RSD, 6.6–12.6 %) and 90.8–111.3 (RSD, 7.1–12.6 %) using 2-naphthol and 8-hydroxyquinoline as a coupler, respectively. The SH-LLME avoids pH adjustment of the final test sample before extraction, and Cu(II) and Fe(III) up to 1 and 6 mg L⁻¹, respectively, can be tolerated. Enrichment factors with the two reagents in that order were 21 and 20, respectively.