云南省不同产地茯苓菌核中汞元素含量研究

茯苓菌核在亚洲具有悠久的药用历史,也是北京传统小吃“茯苓夹饼”原材料。研究旨在测量和评价中国云南地区茯苓菌核的总汞含量。与其他种类蘑菇子实体相比,茯苓菌核汞含量较低。汞含量(干物质)的范围为0.0041~0.019 mg·kg-1,中位数为0.011 mg·kg-1,总体平均值为(0.011±0.004)mg·kg-1,表明云南不同产地茯苓菌核中 Hg含量受到复杂山地类型的影响较大。对每天食用含有50 g 茯苓菌核的茯苓夹饼 Hg摄入量进行健康评估,人均每天Hg摄入量为0.0000034~0.000016 mg·kg-1,按成人体重60 kg计算,人均每天 Hg摄入量为0.0000092~0.00055 mg。研究结果显示,茯苓菌核中 Hg元素含量较低,其摄入量低于健康限量标准。同时,煎煮后的茯苓菌核中 Hg摄入量也低于健康限量标准,由茯苓菌核制成的茯苓夹饼 Hg含量较低。     

Speciation of arsenic using capillary gas chromatography with atomic emission detection

A gas chromatography method with atomic emission detection (GC-AED) for the determination of dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and inorganic arsenic was optimized. The analytes were derivatized in the sample solutions with methyl thioglycolate (TGM) and the products were extracted into cyclohexane before an aliquot of this organic phase was directly injected into the chromatograph. The procedure was applied to the analysis of seawaters, wines, beers and infant foods, the last requiring an additional enzymatic reaction prior to analyte derivatization. Detection limits in seawaters and beverages were 0.05, 0.15 and 0.8 ng mL⁻¹ for DMA, MMA and inorganic arsenic, respectively. In infant foods the detection limits were 1, 10 and 25 ng g⁻¹ for DMA, MMA and inorganic arsenic, respectively. Inorganic arsenic was detected in some of the seawater samples and three of the wines analyzed at concentration levels in the range 1-40 ng mL⁻¹, and DMA in several of the infant foods in the range 20-80 ng g⁻¹. The method was validated by analyzing a certified reference material and by recovery studies. All the samples were also analyzed by hydride generation and atomic fluorescence spectrometry (HG-AFS), which provided data for the total arsenic content.     

Thermoluminescence detection of Korean traditional foods exposed to gamma and electron-beam irradiation

Thermoluminescence(TL) analysis was applied to detect irradiated Korean traditional condiments and soup mixes containing salt(NaCl). These food items, which are commercially irradiated in Korea, showed a consistently high correlation(R²) between the absorbed doses and the corresponding TL responses. It was proved that table salt played a role as an in-built indicator in TL measurements and its concentration in test samples was proposed as a correction factor for varying conditions of TL measurements. Pre-established threshold values were successfully adopted to identify 167 coded samples of Ramen soup mixes, both non-irradiated and irradiated with gamma and electron-beam energy. The TL intensity of irradiated soup mixes decreased with the lapse of time, but was still distinguishable from that of the non-irradiated samples at the fourth month of ambient storage. Expected estimates of absorbed doses, 2.85 and 4.75 kGv were obtained using a quadratic equation with average values of 1.57 and 4.90 kGy, respectively.     

固相萃取-超高效液相色谱-串联质谱法同时测定保健食品中21种非法添加化合物

建立了固相萃取-超高效液相色谱-串联质谱同时测定保健食品中21种非法添加化合物的方法。样品用乙腈超声提取后，采用HLB固相萃取小柱净化，经Waters BEH C18色谱柱（100 mm×2.1 mm，1.7 μm）分离，以10 mmol/L乙酸铵和甲醇为流动相进行梯度洗脱，采用电喷雾电离（ESI）源，在多反应监测模式下检测。结果表明，21种非法添加化合物均呈良好的线性关系，相关系数均≥0.995，不同基质的检出限为3~160 μg/kg，回收率为61.8%~109.3%，相对标准偏差为1.6%~14.7%。该方法可用于减肥类、降脂类、降糖类、降压类保健食品中21种非法添加药物的同时测定。     

Optimization of an analytical methodology for the determination of alkyl- and methoxy-phenolic compounds by HS-SPME in biomass smoke

A sampling and analysis method for the determination of 21 phenolic compounds in smoke samples from biomass combustion has been developed. The smoke is used to make smoked foods, following an artisanal procedure used in some parts of the Canary Islands. The sampling system consists of a Bravo H air sampler, two impingers, each one containing an aqueous solution of sodium hydroxide 0.1 mol L⁻¹, followed by a silica gel trap. The variables optimized to reach the best sampling conditions were volume of absorbent solution and sampling flow. Under the optimum conditions, 100 mL of absorbent solution of NaOH 0.10 mol L⁻¹ and 2 L min⁻¹ for the sampling flow, sampling efficiencies are higher than 80%. Analysis of phenolic compounds was carried out by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC-MS). Five different fiber coatings were employed in this study. By means of a central composite design, extraction time, salt concentration, and pH of the solution were optimized: 65-μm carbowax–divinylbenzene, extraction time 90 min, concentration in NaCl of 35% (m/v), and pH 2 yielded the highest response. Detection limits of phenol and their alkyl derivatives, guaiacol and eugenol, are between 1.13 and 4.60 ng mL⁻¹. 3-Methoxyphenol, 2,6-dimethoxyphenol, and vanillin have detection limits considerably higher. Good linearity (R ²≥0.98) was observed for all calibration curves in the established ranges. The reproducibility of the method (RSD, relative standard deviation) was found to oscillate between 7 and 18% (generally close or lower than 10%).     

HPLC-APCI(+)MS/MS分析动物源性食品中的硝基咪唑类药物残留量

运用高效液相色谱-大气压电离串联四极杆质谱(HPLC-APCI( )MS/MS)内标法分析动物源性食品中多种硝基咪唑类(nitroimidazoles)药物——甲硝唑(MNZ)、地美硝唑(DMZ)、替硝唑(TNZ)、洛硝唑(RNZ)的含量。样品添加氘代标示物HMMNI-D3、IPZ-OH-D3后,用乙腈提取,通过OASIS HLB C18SPE柱净化,Waters Sunfire C18色谱柱分离,采用梯度洗脱,流动相为0.1%甲酸水溶液和0.1%甲酸乙腈溶液;大气压电离源正离子MRM模式检测:MNZm/z172.0/82.1,172.0/128.0;DMZm/z142.0/81.1,142.0/96.1;TNZm/z248.0/121.0,248.0/93.1;RNZm/z201.0/140.0,201.0/110.0;IPZ-OH-D3m/z189.0/125.0,189.0/171.0;HMMNI-D3m/z161.0/58.0,161.0/143.1。方法定量下限(LOQ,S/N>10)0.2μg/kg,在质量浓度0.2~25.0μg/L范围内,峰面积与质量浓度成良好线性(r>0.999 1)。     

Fast analysis of soy isoflavones by high-performance liquid chromatography with monolithic columns

A fast method using high-performance liquid chromatography based on two monolithic columns has been developed for the simultaneous determination of isoflavones extracted from soybeans and derived foods. The 12 main isoflavones were resolved in 10 min in two coupled monolithic columns working at 35 °C using a elution gradient of acidified water (0.1% acetic acid) and methanol (0.1% acetic acid) at a flow rate of 5 mL min⁻¹. Retention time and relative area standard deviations were below 1% for all isoflavones. The method developed was successfully applied to several soy food samples and spiked samples. Total isoflavone concentration in sampled soy foods ranged from 34.28 mg L⁻¹ to 4.29 mg g⁻¹.     

Simultaneous determination of nicotinamide,nicotinic acid,riboflavin, thiamin,and pyridoxine in enriched Brazilian foods by HPLC

The control of the enrichment levels in foods is difficult, due mainly to the lack of appropriate analytical methodologies. The amounts of the five B-group vitamins (nicotinamide, nicotinic acid, ribofla-vin, thiamin, and pyridoxine) have been determined in enriched Brazilian foods by a high-performance liquid chromatography (HPLC) method. Fifty products, such as biscuits, liquid and dry milks, flavored milk drinks, flour, macaroni, and cereals were analyzed. Some products showed the amounts declared on the package. Although some slight quantitative variations were shown in the biscuits, one showed levels of riboflavin 35% lower than the value declared. Of five different corn cereal brands, only one showed the declared vitamin content, the others showing levels 30 % lower than that declared. No B-group vitamins were detected in one brand of enriched macaroni, except for the nicotinic acid naturally present in the flour. On the other hand, one flavored milk drink exhibited vitamins levels 200% higher than the amounts declared and one milk drink mix presented thiamin, riboflavin, and nicotinamide levels 3 to 5 times greater than stated. These results suggest an absence of control of the amount of vitamins in enriched foods.