鱼肉中磺胺类和四环素类药物多残留分析方法的研究

建立了一种同时测定鱼肉中磺胺类和四环素类药物多残留的基质固相分散-高效液相色谱检测方法.待测化合物采用C18柱分离,以3%草酸缓冲溶液-甲醇为流动相,梯度洗脱,流速为0.80mL/min,二极管阵列检测器检测,检测渡长265nm.实验结果表明:磺胺类药物平均加标回收率73.8%～93.8%,相对标准偏差在2.8%～9.2%之间;四环素类药物平均加标回收率79.1 %～91.1%,相对标准偏差在3.5%～8.7%.     

高效液相色谱法测定乳及乳制品中多种四环素类药物残留

建立了高效液相色谱法同时测定乳及乳制品中土霉素、四环素、金霉素、强力霉素残留的的方法。样品通过柠檬酸缓冲溶液提取,MAX固相萃取柱净化浓缩后,采用C18色谱柱,以乙腈-浓度为0.01 mol/L草酸水溶液为流动相梯度洗脱,用紫外检测器于350 nm波长处检测。回收率在90.4%～103.3%,精密度(RSD)为2.09%～4.73%,检出限分别为0.05,0.04,0.06,0.08μg/g。该方法可用于乳及乳制品中这4种四环素类药物残留的同时测定。     

多壁碳纳米管基质固相分散-高效液相色谱测定牛奶中6种四环素

以多壁碳纳米管为吸附材料,建立基质固相分散萃取高效液相色谱法测定牛奶中6种四环素。将多壁碳纳米管、EDTA、草酸和样品研磨混匀装柱,经含甲酸的甲醇洗脱后HPLC多波长紫外检测。6种四环素的检出限0.01～0.03μg/mL,回收率78.7%～105.2%,相对标准偏差小于12%。多壁碳纳米管基质固相分散萃取牛奶中四环素的回收率优于C18,可推广到食品等复杂样品中其他农兽药多残留分析。     

RP-HPLC快速检测牛奶中7中四环素类药物残留量的研究

目的：建立快速检测牛奶中7 种四环素类药物残留的反相高效液相色谱法。方法：用0.1mol/L McIlvaine-EDTA 溶液和50% 三氯乙酸(TCA)溶液共同处理牛奶样品,通过Waters Oasis HLB 固相萃取柱进行净化处理。仪器条件中所用色谱柱为SunfireTM C18(250mm × 4.6mm,5μm)柱,以甲醇- 乙腈-0.01mol/L 草酸(pH2)为流动相,采用梯度洗脱模式。结果：7 种四环素类药物线性范围宽,峰面积和样品浓度在0.05～1μg/ml 范围内呈很好的线性关系,加标平均回收率为78.66%～106%,最低检测限为0.02μg/ml。结论：该方法操作简单、重现性好、检测限低、灵敏可靠,可在14min 内同时将四环素等7 种四环素类药物达到基线分离。     

分散固相萃取-超高效液相色谱-串联质谱检测水产品中14 种喹诺酮类药物

采用基质固相分散的前处理技术,建立一种超高效液相色谱-串联质谱同时检测水产品中14 种喹诺酮类药物的分析方法。样品用5%甲酸-乙腈溶液提取和盐析剂盐析后加入N-丙基乙二胺和十八烷基键合硅胶吸附剂（C18）净化剂进行基质固相分散净化,氮吹复溶后经Waters ACQUITY UPLC BEH C18柱（50 mm×2.1 mm,1.7 μm）分离,以0.2%甲酸溶液和甲醇为流动相梯度洗脱,采用电喷雾离子源正离子多反应监测模式测定,外标法定量。14 种药物在0.50～20.0 μg/L质量浓度范围内呈良好线性,线性相关系数不小于0.995,方法检出限为0.4～1.0 μg/kg,定量限为1.0～3.0 μg/kg。14 种药物在3 个加标水平下的平均回收率为82%～90%,相对标准偏差（n=5）均小于11.0%。本方法简便快速、灵敏度高、实用性强,可作为水产品中14 种喹诺酮类药物残留的快速确证和定量分析。     

改进MSPD-HPLC法快速检测猪血豆腐中镇静剂及雌激素残留

建立改进了的基质固相分散萃取(MSPD)-高效液相色谱法(HPLC/UVD)同时快速检测猪血豆腐中的4种镇静剂(艾司唑仑、阿普唑仑、氯氮和地西泮)及己烯雌酚残留的方法。样品以无水硫酸钠和弗洛里西土(质量比4∶1)为分散剂和净化剂,甲醇为溶剂。色谱条件:C18色谱柱(5μm,250 mm×4.6 mm i.d.),甲醇-乙腈-水(体积比30∶30∶40)为流动相,流速:1.0 m L/min,检测波长235 nm,柱温:30℃。5组分在0.010μg/m L~10μg/m L范围内线性关系良好,相关系数均不低于0.999 2。猪血豆腐中4种镇静剂的方法检出限均为10 ng/g,己烯雌酚的方法检出限为15 ng/g;5组分平均回收率在82.4%~104.5%之间,相对标准偏差为1.7%~3.5%。结果表明该方法简便、快速、经济,适用于猪血豆腐中己烯雌酚及多种镇静剂类药物残留的快速检测。     

分散固相萃取-超高效液相色谱串联质谱法测定 牛肉中7种头孢菌素类药物及其代谢物

目的建立分散固相萃取超高效液相色谱-串联质谱法(dispersion solid-phase extraction with ultra-performance liquid chromatography-tandem mass spectrometry,DSPE-UPLC-MS/MS)同时测定牛肉中7种头孢菌素类药物及其代谢物残留量的方法。方法样品经乙腈-水溶液提取,C_(18)分散固相萃取净化,在电喷雾正离子多反应监测模式下进行定量和定性分析。结果 7种头孢菌素类药物及其代谢物的方法检出限和定量限分别为0.4~0.8μg/kg和1.1~2.3μg/kg。在3个添加浓度水平的平均回收率为68.3%~95.7%,相对标准偏差为1.9%~12.5%。结论该方法快速、准确、灵敏、稳定,能够满足牛肉中头孢菌素类药物残留的检测。     

分子印迹固相萃取-高效液相色谱法检测鸡肉中的四环素类抗生素残留

采用本体聚合法,以盐酸四环素为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂,合成了针对四环素类抗生素具有选择性的分子印迹聚合物。并以此材料作为固相吸附剂与高效液相色谱联用,建立了固相萃取-高效液相色谱技术检测鸡肉中的3种四环素类抗生素痕量残留的方法。实验结果表明,该材料具有较强的吸附性和特异识别性。在0.1 mg/L~1.0 mg/L范围内3种四环素类药物的线性关系良好(R20.99),土霉素、四环素、强力霉素的最低检出限分别为0.13μg/L、0.12μg/L、0.14μg/L,5次重复实验的精密度分别为1.27%、1.31%、1.94%。在鸡肉中添加3个浓度(50μg/kg、100μg/kg、200μg/kg)的四环素类抗生素,回收率分别为88.33%~94.95%、80.94%~88.02%、87.69%~93.08%,RSD分别为2.08%~3.63%、1.46%~2.37%、1.04%~3.03%。这项研究的结果表明目前建立的方法可以用于鸡肉中四环素类抗生素的残留检测。     

分散固相萃取结合液相色谱-串联质谱法测定水产品中11种四环素类药物

采用分散固相萃取结合液相色谱-串联质谱仪,建立水产品中11 种四环素类药物残留的分析方法。样品经Na2EDTA-McIIvaine缓冲溶液分散后,以体积分数1%乙酸乙腈提取,提取液经盐析及脱水后取乙腈层,用C18净化。目标物用C18色谱柱（100 mm×2.1 mm,3 μm）分离,以甲醇和体积分数0.1%甲酸水溶液为流动相进行梯度洗脱,利用电喷雾离子源多反应监测模式进行检测。结果表明：11 种化合物在各自的质量浓度范围内线性关系良好,相关系数均大于0.998;大多数化合物在定量限添加水平下的响应良好,在2 倍和5 倍定量限添加水平下平均回收率普遍大于80%,相对标准偏差为3.2%～10.3%（n=6）;检出限（RS/N=3）和定量限（RS/N=10）分别为2.9～6.1 μg/kg和10～20 μg/kg。该方法简便、快速、灵敏,适用于水产品中11 种四环素残留物的定性、定量分析。     

液相色谱-质谱/质谱法检测饲料中四环素类药物残留

建立液相色谱-质谱/质谱法测定饲料中四环素类(四环素、土霉素、金霉素、强力霉素)药物残留的方法,旨在提高检测效率和检测限度。实验中,采用Na2EDTA-Mcllvainc缓冲溶液提取样品,经Phenomenex Strata-X固相萃取柱净化,进行液相色谱-质谱/质谱法分析。结果表明:四环素类标准品3个添加浓度20、50和100μg/kg的平均回收率为93%~103%,相对标准偏差小于15%,四环素类药物的检测定量限(LOQ):20μg/kg,检出限:5μg/kg。标定曲线的线性范围:10~200μg/L,R0.998。此方法适用于饲料中四环素类药物残留检测。     

褪黑素对小鼠抗氧化作用的影响

目的:研究小鼠在受到脂多糖(LPS)刺激时,褪黑素的抗氧化作用,并探讨其可能机制。方法:用脂多糖建立氧化应激模型,检测血清、小肠、肝脏和脾组织中的ROS含量,肝脏、脾组织中的谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)、丙二醛(MDA)的变化。结果:在LPS刺激后的4h和16h,褪黑素均能降低血清、小肠、肝脏、脾组织中的ROS含量,提升肝脏和脾组织中的GSH-PX、SOD活性,降低MDA含量。结论:褪黑素有助于增强氧化应激小鼠的抗氧化能力,降低组织中NO含量与NO合成酶活性,增加了SOD、GSH-PX等抗氧化酶的活性,保护机体免受氧化损伤。     

Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the Southern part of Chile

The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55–2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of bioaccumulation and biotransformation they will thereafter exhibit.     

Correlation of methylglyoxal with acrylamide formation in fructose/asparagine Maillard reaction model system

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous fructose/asparagine (Fru/Asn) and fructose/asparagine/o-phenylenediamine (Fru/Asn/OPD) model systems were heated at 150 °C for up to 30 min. Methylglyoxal (MG) was the main α-dicarbonyl compounds formed in MR, which was chosen as a representative of α-dicarbonyl compound to investigate the influence on acrylamide (AA) formation. The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 75% of AA was formed through the participation of α-dicarbonyl compounds. The amounts of formation and consumption of MG increased with heating time, and from 12 min of reaction, the consumed amounts of MG accounted for 62.1–90.3% on the basis of total amounts of MG formed in MR, suggesting that most of the MG took part in further reactions. Meanwhile, Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA was 0.931, demonstrating that MG plays a role in AA formation.     

DETERMINATION OF ANIONS IN BEER BY ION CHROMATOGRAPHY

A method relying on ion chromatography, with suppressed ion detection, for the determination of anions in beer, has been collaboratively tested by members of the American Society of Brewing Chemists, the European Brewery Convention and the Brewery Convention of Japan. Precision values obtained for the determination of chloride, sulphate and phosphate in beer were judged to be acceptable. Repeatability (r₉₈) and reproducibility (R₉₈) values for chloride were 5.7, 12.6, 12.5 and 15.0, 38.4, 36.8 respectively at corresponding mean levels of 68.7, 218.6 and 322.5 mg/litre. r₉₈ and R₉₈ values for sulphate were 7.5, 6.2, 7.6 and 44.8, 54.0, 46.5 respectively at corresponding mean levels of 101.4, 205.1 and 122.6 mg/litre. r₉₈ and R₉₉ values for phosphate were 14.1, 11.9, 24.9 and 78.7, 53.8, 84.0 at corresponding mean levels of 411.5, 224.1 and 397.5 mg/litre. Whilst the r₉₈ value for nitrate was acceptable, the value for R₉₈ was unsatisfactory. The ion chromatographic method for determining chloride, sulphate and phosphate in beer is recommended for use and inclusion in Analytica -EBC as an International Method.     

气相色谱法检测饮料中二羰基化合物

建立同时在线检测丙酮醛和乙二醛的气相色谱方法。确定检测二羰基化合物的最佳条件为：以丁二酮为内标,以邻苯二胺为衍生化试剂,邻苯二胺的用量67 倍于二羰基化合物、衍生化时间10 min、萃取溶剂二氯甲烷、超声时间15 min、萃取2 次、柱箱初始温度40 ℃、程序升温5 ℃/min,色谱柱载气流量2.0 mL/min,分流比1∶1。丙酮醛和乙二醛的定量限（RSN≈10）分别为0.06 mg/L和0.08 mg/L,检出限（RSN≈ 3）分别为0.02 mg/L和0.03 mg/L,方法灵敏度高。     

高效液相色谱法同时检测6种甜味剂

建立同时测定6种人工合成甜味剂阿斯巴甜、糖精钠、甜蜜素、安塞蜜、纽甜、甜聚糖甙的高效液相色谱分析方法。以Platicil ODS柱为分离柱,20mmol/L硫酸铵缓冲溶液(pH4.4)-乙腈为流动相,进行梯度洗脱。采用二极管阵列检测器进行检测,整个分离过程在30min内完成。6种甜味剂在0.4～120mg/L范围内其质量浓度与峰面积的线性关系良好,相关系数为0.99967～0.99998,在4.0～10.0mg/kg范围内,样品加标回收率为85%～107%;相对标准偏差小于3.2%。该方法简便、快速,净化效果较好,可用于食品中6种甜味剂的同时测定。     

嘧菌酯处理对厚皮甜瓜POD和CAT活性的影响

以厚皮甜瓜(Cucumis melonL.)作为实验材料,研究嘧菌酯处理对厚皮甜瓜采后过氧化物酶和过氧化氢酶活性的影响,实验结果表明:甜瓜经50、100、200mg/L嘧菌酯浸泡处理后,其果实的过氧化物酶和过氧化氢酶活性均有所变动,其中,100mg/L嘧菌酯处理,两种酶的活性均处于稳定上升趋势,到第14天达到最高值,此后呈下降趋势,但到第21天时,酶活性仍高于对照。     

亚精胺对小鼠骨骼肌自由基代谢影响及抗疲劳的效果研究

目的：研究亚精胺（spermidine,SPD）对骨骼肌自由基代谢的影响以及抗疲劳作用。方法：实验分为生理盐水组、SPD低剂量组（0.5 mmol/（kg·d））、中剂量组（1.0 mmol/（kg·d））、高剂量组（1.5 mmol/（kg·d））以及西洋参口服液阳性对照组（总皂苷30 mg/（kg·d））,每周灌胃6 d共30 d,每次灌胃前称量小鼠体质量调整灌胃溶液量,灌胃期间进行每天45 min无负重游泳训练。各组随机选取10 只小鼠测试力竭游泳时间;各组剩余10 只负重游泳30 min,休息30 min后取材,检测血清肌酸激酶（creatine kinase,CK）、骨骼肌谷胱甘肽-过氧化物酶（glutathione peroxidase,GSH-Px）、总超氧化物歧化酶（total-superoxide dismutase,T-SOD）、琥珀酸脱氢酶（succinate dehydrogenase,SDH）活性和骨骼肌丙二醛（malondialdehyde,MDA）含量。结果：与生理盐水组比较,SPD能显著延长小鼠力竭游泳时间（P＜0.05）;低、中剂量组骨骼肌中GSH-Px、T-SOD、SDH酶活性显著提高（P＜0.05）,MDA含量显著降低（P＜0.05）;SPD组与西洋参组比较,低、中剂量抗疲劳效果有非常显著性（P＜0.05）差异,高剂量抗疲劳效果略优（P＞0.05）。结论：0.5～1.0 mmol/（kg·d） SPD可以增加抗氧化酶的活性,减少自由基的积累,提高骨骼肌细胞膜代谢能力和抗损伤能力,显著推迟小鼠疲劳发生。     

亚甲基蓝对单增李斯特菌菌膜的光动力杀伤作用

探讨单增李斯特菌（Listeria monocytogenes,LM）生物菌膜的生长特性及亚甲基蓝对LM生物菌膜光动力杀伤作用。通过结晶紫染色法判断与观察LM生物菌膜的形成并用酶标仪在595 nm波长处对其不同生长阶段的生物量进行测定,同时通过细菌平板菌落计数法研究亚甲基蓝对LM生物菌膜的光动力杀伤作用。结果表明：结晶紫染色法可用于定性判断与观察LM生物菌膜,且随着培养时间的延长,LM生物菌膜生物量不断增加,形成的网状结构越来越致密。当光敏剂质量浓度为10 μg/mL的亚甲基蓝在光功密度为200 mW/cm2 的可见光照射30 min时,即可使LM生物菌膜的失活率达到99.99%以上,其菌落数降低了4.08（lg（CFU/mL））。亚甲基蓝对LM生物菌膜的光动力灭活作用非常显著,其杀伤效果主要取决于光敏剂质量浓度和光照时间。