净化柱结合超高效液相色谱—串联质谱检测动物源性食品中16种喹诺酮药物

目的：加强动物源性食品安全检测市场监管。方法：动物源性食品样品使用80%乙腈（含0.2%甲酸）提取，净化柱（Speedy Prep^-Quino 1）净化后，利用超高效液相色谱—串联质谱检测16种喹诺酮类药物残留。结果：16种喹诺酮类药物的线性范围为1.6～40.0 μg/kg，相关系数r≥0.996 1，检出限为0.14～0.80 μg/kg，定量限为0.47~2.68 μg/kg。在净化柱前处理后7个基质加标回收率为62%~112%，相对标准偏差为0.9%~18.7%。结论：该方法具有检测速度快、灵敏度高的特点，适用于羊肉、鸭肉、牛肉、鱼肉、鸡蛋、猪腰、鸭皮等动物源性食品。     

分散固相萃取—超高效液相色谱—四极杆/飞行时间质谱法测定禽肉中松香酸类物质

目的：建立超高效液相色谱—四极杆/飞行时间质谱法（UPLC-Q-TOF/MS）测定禽肉中松香酸类物质。方法：样品使用乙腈提取，盐析分层后，上清液由C₁₈固相萃取剂净化，UPLC-Q-TOF/MS电喷雾负离子模式测定。结果：3种松香酸类物质在10~500 μg/L质量浓度范围内线性关系良好，相关系数R²＞0.998，平均回收率为87.8%~98.5%，相对标准偏差（RSDs）为1.99%~6.71%（n=6）；方法检出限（LODs）为10 μg/kg，方法定量限（LOQs）为20 μg/kg。结论：试验方法操作简便，快捷，回收率和灵敏度高，精密度好，能够满足禽肉中3种松香酸类物质的检测需求。     

分散固相萃取—超高效液相色谱—串联质谱法测定液态奶中11种农药残留量

目的：评估液态乳中农药残留量的安全性。方法：建立同时测定11种农药残留的超高效液相色谱—串联质谱法。待测样品经乙腈提取，C₁₈和PSA固相萃取剂净化，经色谱柱Xbridge BEH C₁₈ （100 mm×2.1 mm，1.7 μm）分离，多反应监测模式进行测定，并使用响应曲面法优化前处理参数。结果：前处理的最佳条件为乙腈用量10 mL，C₁₈用量50 mg，PSA用量30 mg。11种农药在1.0~100.0 μg/L的浓度范围内线性关系良好，相关系数（R²）均＞0.999。在10，20，100 μg/kg添加水平内，11种农药的平均回收率为82.7%~102.0%，相对标准偏差为2.89%~8.87%，检出限和定量限分别为2.0~3.0，5.0~10.0 μg/kg。结论：该方法操作简便，分析时间短，回收率高，重现性好，能够准确定性定量分析液态乳中11种农药残留量。     

超高效液相色谱—三重四极杆质谱法测定黄瓜中双炔酰菌胺残留

目的：建立一种超高效液相串联三重四极杆质谱检测黄瓜中双炔酰菌胺含量的方法。方法：黄瓜试样经乙腈超声提取后，采用分散固相萃取法（QuEChERS）进行净化，超纯水稀释，用0.1%甲酸水和乙腈作为流动相进行液相色谱—串联质谱测定。采取电喷雾（ESI）离子源在正离子检测模式下，对双炔酰菌胺进行多反应监测（MRM），并使用外标法进行定量。结果：在0.01～0.50 μg/mL质量浓度范围内，双炔酰菌胺具有良好的线性关系，R²=0.999 8；在10，50，100 mg/mL 3种不同加标水平下，双炔酰菌胺回收率为 89.6%～96.0%，相对标准偏差（RSD）为0.72%～1.80%（n＝6）。试验方法检出限为0.003 mg/kg；定量限为0.009 mg/kg。结论：试验方法前处理过程无需浓缩，操作简便，分析灵敏度高、稳定性好、重现性高，适用于黄瓜中双炔酰菌胺的定性与定量分析。     

高效液相色谱法测定奶粉中玉米黄质含量

目的 本文建立了一种使用高效液相色谱快速检测奶粉中玉米黄质含量的方法。方法 奶粉样品用蛋白酶在45℃条件下振荡酶解30 min,正己烷/丙酮(9：1)重复提取2次,旋转蒸发浓缩至近干,正己烷/乙酸乙酯(65：35)复溶后,用Si 60(100 mm×2.1 mm,5 μm)色谱柱经高效液相色谱紫外检测器测定,外标法定量测得。结果 试验结果表明,玉米黄质在14.018 min附近出峰,玉米黄质浓度在0 μg/mL-4.0 μg/mL范围内呈良好线性关系(R_²=0.99982)。空白奶粉样品中添加玉米黄质含量为63.35 μg/100 g,126.7 μg/100 g,316.75 μg/100 g时,加标回收率在95.8%～96.7%之间,相对标准偏差在1.1%-3.9%之间。当取样量为2 g,定容体积为5 mL时,检测限为20 μg/100 g,定量限为50 μg/100 g。结论 该检测方法相对于其他前处理较简单,具有较高准确度、灵敏度、稳定性,可以满足奶粉中玉米黄质含量的检测。     

固相萃取—超高效液相色谱—质谱法测定食用香精中3种甲基咪唑类物质

目的：同时、快速检测食用香精中3种甲基咪唑化合物。方法：利用5%三氯乙酸溶液提取食用香精，再利用PCX混合阳离子固相萃取柱净化提取液，最后利用超高效液相色谱—质谱法和内标法进行定性和定量分析。结果：3种甲基咪唑化合物在5.0~400.0 ng/mL内呈良好线性关系，相关系数R²≥0.997。3种甲基咪唑检出限为0.030~0.450 μg/kg，定量限(LOQ)为0.10~1.50 μg/kg。3种甲基咪唑的加标回收率在82.8%~111.7%，相对标准偏差RSD在1.3%~9.3%。结论：该方法简单高效、准确度高，可作为食用香精中甲基咪唑的定量检验方法。     

凝胶渗透色谱-高效液相色谱法测定火麻仁油中Δ9-四氢大麻酚含量

目的 建立使用凝胶渗透色谱(GPC)净化,高效液相色谱(HPLC)分析测定火麻仁油中Δ⁹-四氢大麻酚(Δ⁹-THC)的检测方法。方法 样品经环已烷和乙酸乙酯溶解,经GPC净化分离,再以Agilent Eclipse XDB-C₁₈色谱柱(150 mm×4.6 mm,3 μm)分离,以乙腈-水流动相洗脱,二级管阵列检测器分析,外标法定量。结果 该方法在0～500 μg/L浓度内,线性相关系数(r)＞0.999,方法检测限(LOD)为0.05 mg/kg,定量限(LOQ)为0.17 mg/kg。加标回收率在84.6%～101.8%之间,相对标准偏差为3.2%～4.7%(n=6)。在实际样品检测中,10种不同品牌的火麻仁油中Δ⁹-THC含量在0.40～5.82 mg/kg之间。结论 该方法稳定性好,灵敏度高,适用于火麻仁油样品中Δ⁹-THC的检测分析。     

超临界色谱串联静电场轨道阱质谱法测定蔬菜水果中高极性农药残留

目的 建立基于超临界色谱技术（SFC）结合静电场轨道阱质谱法（Q-Orbitrap）对蔬菜水果中12种高极性农药残留量的测定方法。方法 样品用1%酸化甲醇提取,提取液经分散固相萃取净化,以Ultra Silica柱（150 mm×2.1 mm, 3 μm）和Obelisc R柱（150 mm×2.1 mm, 5 μm）为分离柱,使用超临界色谱-串联静电场轨道阱质谱（SFC-Q-Orbitrap）测定,以分段式混合产物离子扫描,采用同位素内标校准曲线定量。结果 12种农药在20.0～500 μg/L范围内线性关系良好,决定系数（R²）均＞0.997,在0.05、0.20 mg/kg 2个加标浓度下的平均回收率为80.2%～120%,相对标准偏差（RSD,n＝6）为2.14%～14.6%,方法的检出限为0.010 1～0.016 2 mg/kg,定量下限为0.050 mg/kg。结论 方法具有操作简单、专一性强、定量准确、测定高效等优点,经实际样品测试,可满足蔬菜水果中高极性农药残留的检测。     

柱前衍生—高效液相色谱荧光检测法测定乳制品中6种母乳寡糖

目的：建立一种普及性强、灵敏度高,并能同时测定乳制品中6种母乳寡糖的高效液相色谱—荧光检测分析方法。方法：样品经冰醋酸沉淀,滤纸过滤后,经2-氨基苯甲酰胺溶液衍生,离心后经有机滤膜过滤,用AdvanceBio Glycan Map色谱柱分离,以乙腈-50 mmol/L甲酸铵溶液（pH 4.4）为流动相,梯度洗脱分离,并使用荧光检测器检测。结果：6种母乳寡糖在1.00～400.0 mg/L质量浓度范围内线性关系良好,相关系数均＞0.999,方法检出限为4.1～10.9 mg/kg,回收率为71.3%～90.2%,日内相对标准偏差（RSD）为1.0%～6.3%,日间相对标准偏差＜10.0%。结论：该方法简单、快捷,可有效降低衍生峰的干扰,适用于乳制品中3′-岩藻糖基乳糖、2′-岩藻糖基乳糖、乳糖-N-四糖、乳糖-N-新四糖、3′-唾液乳糖和6′-唾液乳糖6种母乳寡糖的日常检测。     

超高效液相色谱-串联质谱法测定聚氯乙烯食品接触材料中3种柠檬酸酯增塑剂

目的 建立超高效液相色谱-串联质谱法测定聚氯乙烯食品接触材料中3种柠檬酸酯类增塑剂的方法。方法 采用正己烷/二氯甲烷（1∶1，V/V）提取，经硅胶固相萃取柱净化，乙腈/乙酸乙酯（1∶4，V/V）洗脱，进入UPLC-MS/MS分析，以乙腈和超纯水做流动相，经BEH C₁₈色谱柱（2.1 mm×50 mm，1.7 μm）分离，采用ESI源在MRM正离子模式下检测，外标法定量。结果 3种化合物在线性范围内决定系数R²>0.996，方法检出限0.1~0.6 μg/kg，定量限0.3~2.2 μg/kg，回收率为70.3%~103.1%，相对标准偏差为0.9%~9.8%。结论 该方法分析快速、灵敏、准确，适用于塑料材料中柠檬酸酯类增塑剂含量的检测，为新型增塑剂的添加使用监管提供方法。     

Plant biotechnology--genetic engineering to enhance plant salt tolerance

Plants not only provide food to humans and animals, but also provide a large number of non-food products of industrial and chemical importance. Moreover, they have the ability to purify the air, soil and water on the earth. Various trials to genetically improve the potential of plants are actively in progress. Salt-tolerance would be an especially important ability to bestow upon plants for agricultural and industrial purposes, because high salinity conditions are ubiquitous on earth and represent major barriers to growth. Enhancement of resistance against both hyper-osmotic stress and Na+ toxity is necessary for successful molecular breeding of salt tolerant plants. Introduction of genes for osmolyte bio-synthesis is useful to increase hyperosmotic tolerance of plant cells. It is introduced in this review that genetically engineered ectoine synthesis results in increased hyperosmotic tolerance of tobacco cells. High concentrations of Na+ reduce cellular activity by interfering with vital Na+-sensitive enzymes and by affecting K+ transport. Understanding the regulation of K+ and Na+ homeostasis is thus indispensable for enhancement of plant Na+ tolerance. My research group is investigating the Na+ efflux activity of the yeast Na+-ATPase (Ena1) when installed in the plasma membrane of plant cells, and the rice K+-Na+ co-transporters (HKT) that contribute to the regulation of K+ and Na+ uptake in root cells.     

均匀色空间下红葡萄酒颜色量化分级研究

以宁夏贺兰山东麓产区2012年和2013年瓶储陈酿的13个红葡萄酒样品为材料,采用紫外可见分光光度法和国际照明委员会推荐的CIE L*a*b*均匀色空间参数,来量化葡萄酒的颜色指数,初步研究均匀色空间下红葡萄酒颜色的量化分级。数据量化结果表明:在标准光源D65下,所测试的红葡萄酒色相分为3级,紫红、胭脂红、宝石红;彩度分为5级,灰、淡、中、浓、鲜艳;明度分为5级,中等、稍亮、较亮、亮、明亮。建立CIE L*a*b*下的模型:Ry CX(1-5)LX(1-5)、Rz CX(1-5)LX(1-5)、Rb CX(1-5)LX(1-5),试验表明13种酒样分布在Ry C5+L2+、Ry C4+L3+、Rz C4+L2+、Rz C3+L3+、Rz C3+L4+、Rz C2+L4+、Rb C2+L4+、Rb C+L5+以上8级。     

The combination of stable isotope abundance ratios of H,C, N and S with Sr/Sr for geographical origin assignment of orange juices

Within the EU-project “Pure Juice” established stable isotope methods (δ²H, δ¹³C, δ¹⁵N) have been applied and improved in order to determine and verify the geographical origin of orange juices. In addition, new approaches employing analyses of δ³⁴S and ⁸⁷Sr/⁸⁶Sr have been developed and tested. Approximately 150 authentic orange juice samples from several regions in North- and South-America, Africa and Europe have been analysed. A discrimination of orange producing regions, based on the results which ultimately depend on geographical, climatic and lithological differences was successfully performed. Furthermore, we demonstrate that blending of single strength juice by adding concentrate can be revealed by comparing ⁸⁷Sr/⁸⁶Sr of soluble and insoluble components of the juices. We conclude that regional assignment of orange juice samples is most successful when single parameters are combined in a “multi-element approach”.     

Molecular structure and gene analysis of Ce3+ -induced methanol dehydrogenase of Bradyrhizobium sp. MAFF211645

The molecular structure and nucleotide sequence of Ce(3+)-induced methanol dehydrogenase (MDH) of Bradyrhizobium sp. MAFF211645 were investigated. The addition of 30 μM Ce(3+) to 1/10 nutrient broth containing 0.5% methanol remarkably increased MDH activity. Furthermore, La(3+) increased MDH activity, but other heavier rare earth and metal elements did not have the same effect. MDH increased by Ce(3+) was purified by sequential column chromatography, and the purified MDH migrated as a single band with an apparent molecular weight of 68 kDa on SDS-PAGE. The apparent molecular weight of native MDH was estimated to be 108,000 by gel chromatography. The MDH was comprised of two identical subunits. N-terminal 23-amino acid sequence, 1-NDELHKMAQNPKDWVMPAGDYAN-23, of the purified MDH exhibited 91.3% identity to that of the MDH large subunit-like protein encoded by mxaF' of Bradyrhizobium japonicum USDA110. Nucleotide sequencing of the MDH gene of strain MAFF211645 yielded a deduced amino acid sequence comprising 601 amino acid residues, an N-terminal signal peptide, and a mature MDH comprising 578 amino acid residues with a predicted molecular mass of 62,918 Da. Further analysis of the deduced amino acid sequence of mature MDH revealed that the functional amino acids in its active site, such as two adjacent Cys residues, and bacterial quinoprotein signatures 1 and 2 were conserved. These results indicate that Ce(3+)-induced MDH encoded by mxaF' may be involved in methanol metabolism in Bradyrhizobium sp. MAFF211645.     

基于掺杂型石墨烯量子点构建关—开型电化学发光传感器连续检测Fe3+和F-

目的：研究石墨烯量子点的电化学发光性能。方法：制备发光强度高、性能稳定的氮硫掺杂石墨烯量子点（NS-GQDs）,并构建关—开型电化学发光（ECL）传感器以实现对Fe³⁺和F-的连续检测。结果：在0.1~460.0 μmol/L范围内,Fe³⁺浓度与ECL猝灭值呈良好的线性关系,检出限为0.028 μmol/L;在1~5 600 μmol/L范围内,F^-浓度与ECL恢复值呈良好的线性关系,检出限为0.62 μmol/L。结论：NS-GQDs ECL信号的猝灭和恢复具有较好的可逆性,可应用于饮用水中Fe³⁺和F^-的连续检测。     

Variations in the transfer of radiocesium (Cs) and radiostrontium (Sr) from milk to cheese

This study aimed to compare the transfer of 2 manmade radionuclides, radiocesium (¹³⁷Cs) and radiostrontium (⁹⁰Sr), from cow milk to whey and cheese in 3 different types of French cheese production with rennet coagulation. Most of the ¹³⁷Cs was present in the aqueous phase and became concentrated in the whey. For ¹³⁷Cs transfer to whey, the processing factor (Pf; i.e., the ratio of the activity concentrations) ranged between 0.86 and 1.30 (n = 12). The food processing retention factor (Fr), calculated using the processing efficiency, ranged between 0.85 and 1.19 (n = 9). No statistical difference of Pf and Fr to whey is identified for ¹³⁷Cs and the cheese products. The Pf calculated for ⁹⁰Sr transfer to cheese ranged between 3.95 and 12.16, with significant differences depending on the type of cheese. In addition, a linear correlation is observed between ⁹⁰Sr Pf to cheese and the Ca level in the cheese (r² = 0.57). Thus, the Pf is enhanced in hard cheeses that are enriched in calcium. This is confirmed by nearly constant Fr values, ranging between 0.66 and 0.83.     

Online determination of <Superscript>2</Superscript>H/<Superscript>1</Superscript>H and <Superscript>13</Superscript>C/<Superscript>12</Superscript>C isotope ratios of cinnamaldehyde from different sources using gas chromatography isotope ratio mass spectrometry

The combination of gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) and gas chromatography-pyrolysis-isotope ratio mass spectrometry (GC-P-IRMS) is applied to the authenticity assessment of cinnamaldehyde from various sources. For that reason, cinnamon oils were self-prepared by steam distillation from three different varieties of cinnamon bark on the market, C. ceylanicum (ceylon), C. cassia (cassia) and C. burmanii (cassia vera). Furthermore, the so-called wood cinnamon was investigated, which is produced from the outer bark of older branches of cinnamon of minor quality. Self-prepared oils were analysed from commercial cinnamon powder. In addition several commercial samples of cinnamon oil and cinnamaldehyde, some of them declared to be natural, were investigated. ²_V-SMOW and ¹³C_V-PDB values of cinnamaldehyde were determined and characteristic authenticity ranges were deduced, allowing the differentiation between synthetic and natural samples. By correlation of both the ²_V-SMOW and ¹³C_V-PDB values, characteristic authenticity ranges were defined for ceylon, cassia and wood cinnamon. The ²_V-SMOW and ¹³C_V-PDB values of cassia vera samples are in the range of cassia. By comparing the ²_V-SMOW values of different self-prepared samples (ground bark, distillate) of cinnamon determined by TC/EA-IRMS with the corresponding GC-IRMS values, online GC-IRMS methods are proved to be essential in the authentication of complex natural products.     

Gastric H+, K+-ATPase Inhibition,and Antioxidant Properties of Selected Commonly Consumed Vegetable Sources

Oxidative stress and upregulation of gastric H⁺, K⁺-ATPase enzyme activity have been known to cause ulcer pathogenicity for which safer drugs are yet to be identified. Aqueous extracts of seven commonly consumed vegetable sources were screened for inhibition of H⁺, K⁺-ATPase and antioxidant activities. Results indicated that Z. officinale (Ginger) followed by M. arvensis (Pudina) are potent gastroprotective sources with inhibition of H⁺, K⁺-ATPase of IC₅₀ of 18.3 ± 0.7 and 25.2 ± 0.9 μg gallic acid equivalents/ml respectively, which is almost equivalent or better than the known inhibition of H⁺, K⁺-ATPase—Omeprazole (IC₅₀ ?27 μg/ml). Further, all these vegetable extracts showed multi-potent antioxidant activity, such as free radical scavenging, reducing power ability, and inhibition of lipid peroxidation, which are required to inhibit complex steps of ulcerations. On the basis of the absolute amounts and potency of inhibition of H⁺, K⁺-ATPase as well as antioxidant activity of individual phenolic acids, the relative percentage contribution of phenolic acids from different vegetable extracts to both inhibition of H⁺, K⁺-ATPase and antioxidant activity was calculated and data revealed that gentisic and protocatechuic acid contributes significantly to both inhibition of H⁺, K⁺-ATPase and antioxidant activity.     

Artificial radioactivity of Finnish vegetables in the 2000s

A survey on long-lived artificial radionuclides ¹³⁷Cs and ⁹⁰Sr in vegetables produced in Finland was carried out in 2009–2010. The mean ¹³⁷Cs concentrations of all the outdoor vegetables were well below 0.5 Bq kg^?1, ranging from <0.01 to 8.15 Bq kg^–1 (fresh weight). The highest ¹³⁷Cs contents were found in potato and root vegetables. The uneven distribution of the ¹³⁷Cs deposition after the Chernobyl accident in 1986 was still seen in the ¹³⁷Cs contents of outdoor vegetables. The ¹³⁷Cs contents of greenhouse vegetables varied from <0.01 to 9.3 Bq kg^?1, and the highest concentrations were found in organic lettuce grown in peat pots. The concentrations of ⁹⁰Sr in the vegetables varied from 0.0087 to 0.17 Bq kg^?1 fresh weight. The mean effective dose resulting from ¹³⁷Cs and ⁹⁰Sr in vegetables in 2009–2010 was <0.3 µSv a^?1 and poses no health risk to the consumers.     

Passage of stable isotope-labeled grass silage fiber and fiber-bound protein through the gastrointestinal tract of dairy cows

Fractional passage rates are required to predict nutrient absorption in ruminants but data on nutrient-specific passage kinetics are largely lacking. With the use of the stable isotope ratio (δ) as an internal marker, we assessed passage kinetics of fiber and fiber-bound nitrogen (N) of intrinsically labeled grass silage from fecal and omasal excretion patterns of δ¹³C and δ¹⁵N. In a 6 × 6 Latin square, lactating dairy cows received grass silages [455 g/kg of total diet dry matter (DM) ] in a 2 × 3 factorial arrangement from ryegrass swards fertilized at low (45 kg of N/ha) or high (90 kg of N/ha) levels of N and harvested at 3 maturity stages. Feed intake (16.7 ± 0.48 kg of DM/d; mean ± standard error of the mean) and milk yield (26.7 ± 0.92 kg/d) increased at the high level of N fertilization and at decreasing maturity. Nutrient digestibility decreased with increasing plant maturity, particularly at the high level of N fertilization, essentially reflecting dietary treatment effects on the nutritional composition of the grass silage. Fractional rumen passage rates (K₁) were highest and total mean retention time in the gastrointestinal tract (TMRT) was lowest when based on the external marker chromium mordanted fiber (Cr-NDF; 0.047/h and 38.0 h, respectively). Fecal δ¹³C in the acid detergent fiber fraction (¹³CADF) provided the lowest K₁ (0.023/h) and the highest TMRT (61.1 h) and highest peak concentration time (PCT; 24.3 h) among markers. In comparison, fecal fiber-bound N (¹⁵NADF) had a considerably higher K₁ (0.032/h) and lower TMRT (46.4 h) than ¹³CADF. Total N (measured with ¹⁵NDM) had a comparable K₁ (0.034/h) to that of ¹⁵NADF but provided the highest fractional passage rates from the proximal colon-cecum (K₂; 0.37/h) and lowest PCT (17.4 h) among markers. A literature review indicated unclear effects of grass silage maturity on K₁ and unknown effects of N fertilization on K₁. Our study indicated no effect of advancing maturity on fecal K₁ and a trend for K₁ to increase with the high level of N fertilization. Parameter K₂ increased, whereas PCT and TMRT generally decreased with the high level of N fertilization. Omasal digesta sampling largely confirmed results based on fecal sampling. Results indicate that the use of δ¹³C and δ¹⁵N can describe fiber-specific passage kinetics of forage.