培养液中有机酸代谢产物-乙酸测定方法的改进

目的解决培养液中有机酸代谢产物-乙酸检测方法中存在的色谱分离效果差和色谱柱使用寿命短的问题。方法培养液酸化后,用丙酮和乙醚提取乙酸,气相色谱进行检测。结果用该法测定培养液中乙酸的含量,相对标准偏差为1.7%～4.1%,回收率为85.8%～94.6%。结论该方法具有操作快速、简便、准确等优点,完全可以满足菌株分类、鉴定的需要。     

用棒状薄层色谱扫描仪分析饲料中的脂类

为了更好地了解饲料中的脂类成分,研究了用棒状薄层色谱扫描仪分析饲料中脂类的方法.饲料样品经乙醚浸提,再用棒状薄层色谱扫描仪分析提取物中的脂类组成.通过对自制的河蟹饲料进行分析,结果显示:甘油一酯、甘油三酯、游离脂肪酸、胆固醇和磷脂在粗脂肪中的含量分别是0.72%、29.61%、0.92%、1.75%和67.01%,表明将棒状薄层色谱扫描仪应用于饲料脂类的分析中切实可行.     

芦蒿化学成分的分析

用极性溶剂提取干芦蒿的活性物质,并运用气相色谱-质谱联用法对芦蒿化学成分进行分析,同时用气相色谱面积归一化法测定各成分的相对百分含量。结果测得49种物质,有石竹烯、冰片、桉叶醇、o-薄荷-1(7)、8-二烯-3-醇、植醇,含量分别为13.946%、1.105%、1.948%、1.697%、2.132%。     

大米中吡虫啉和噻嗪酮残留分析方法

研究了分别用高效液相色谱和气相色谱测定大米中吡虫啉和噻嗪酮残留量的检测方法。采用乙腈作为大米中吡虫啉和噻嗪酮的共同提取溶剂,部分提取溶液通过氟罗里硅土固相萃取小柱净化,以Wa-ters-C18色谱柱为分离柱,乙腈–水(20∶80,体积比)为流动相,用高效液相色谱二极管阵列检测器检测(检测波长270 nm)吡虫啉的残留量;部分提取溶液通过氨基固相萃取小柱净化,以弹性石英玻璃毛细管柱为分离柱,用气相色谱电子俘获检测器检测噻嗪酮的残留量。结果表明,样品在不同水平的加标回收试验中,吡虫啉的平均回收率为89.2%～96.4%,相对标准偏差为2.5%～8.5%;噻嗪酮的平均回收率为86.6%～105.8%,相对标准偏差为2.6%～5.5%;两种农药的最低检出浓度均为0.02 mg/kg。该测定方法简单、准确、精密度高、重现性好。     

测定硫酸软骨素相对分子质量及其分布的方法

开发了一种简单、微量的测定硫酸软骨素相对分子质量(Mr)的方法。首先用Mr已知的硫酸软骨素校正葡聚糖凝胶G-200色谱柱和琼脂糖凝胶6B色谱柱。然后采用凝胶色谱法用已校正的色谱柱测定Mw未知的硫酸软骨素样品的Mr及其分布,并考察洗脱液离子强度变化的影响。在95%置信度下,重复测定的Mw均值变动为Mw±3%。     

肉制品中山梨酸、苯甲酸的气相色谱分析方法的研究

建立了肉制品中山梨酸和苯甲酸的气相色谱毛细管色谱柱检测方法。样品用石油醚-乙醚高速匀浆的方法提取后,通过改变其酸碱度而改变其在有机相和水相中分配比的方法,去除脂肪等杂质的干扰,用FFAP毛细管色谱柱FID检测器进行检测。方法的变异系数在1.2%～3.9%之间,回收率在89.0%～99.2%之间,最低检出限为1mg/kg。该方法具有步骤简单、准确度和灵敏度高的特点,非常适用于肉制品中山梨酸和苯甲酸的检测。     

固相萃取和高效液相色谱法测定甜茶中的黄酮类物质

研究了用固相萃取预分离,高效液相色谱法测定甜茶中黄酮类物质的方法。甜茶中的黄酮用80%乙醇溶液回流提取,提取液用WatersSep-Pak-C18固相萃取小柱预分离脱脂,以WatersNova-Pak-C18(3.9×150mm,5μm)色谱柱为固定相,以0.05mol/L磷酸二氢钾缓冲溶液和甲醇的比例为40:60(V/V)为流动相,在该色谱条件下,甜茶中主要的黄酮成分均达到基线分离;用紫外二极管矩阵检测器在360nm波长处检测,并作了色谱峰纯度分辨。方法标准回收率为97%～103%,相对标准偏差为0.87%～2.2%。     

芝麻香型白酒中健康功能因子四甲基吡嗪测定方法的对比研究

建立了用气相色谱内标法、液相色谱外标法和液相色谱质谱联用外标法测定芝麻香型白酒中的吡嗪类健康功能因子四甲基吡嗪的方法,并对3种方法检测四甲基吡嗪的回收率和精密度进行了比较研究。3种方法测定酒样中四甲基吡嗪的RSD分别为5.39%～3.05%、4.00%～2.36%和3.20%～1.76%,回收率分别为93.33%～98.44%、94.67%～100.33%和95.33%～99.67%,3种方法的回收率和精密度均可以满足白酒厂日常检验的要求。进一步研究发现,液相色谱质谱法测定白酒中四甲基吡嗪效果最好。     

超高效液相色谱法测定乳及乳制品中维生素D的含量

目的建立用正相高效液相色谱硅胶柱净化维生素D,通过反相超高效液相色谱测定乳及乳制品中维生素D的含量的一种快速检测方法。方法样品经氢氧化-–钾皂化后,用石油醚萃取,萃取液经无水硫酸钠脱水、旋蒸,定容,用正向色谱净化,反相超高效液相色谱用以0.1mL/min流速的甲醇/水(97:3V:V)为流动相,采用WatersACQUITY UPLC BEH C18色谱柱分离,紫外检测器检测,内标法定量。结果维生素D3浓度在0.05–1.00μg/mL内标准曲线相关系数(r~2)均大于0.995。在质量分数为0.5、1.0、2.0μg/mL 3个加标水平下,加标回收率为65.0–115.0%,相对标准偏差为0.1%–1.4%。结论该方法简便、快速、实用、准确,各项技术指标满足标准的要求,可用于乳及乳制品中维生素D的定量检测。     

加速溶剂萃取/气相色谱-质谱法测定糖果包装材料中的双酚A

建立用加速溶剂萃取/气相色谱-质谱法测定糖果包装材料中双酚A的分析方法。样品用二氯甲烷-丙酮作提取剂,加速溶剂萃取仪提取,经BSTFA+TMCS衍生化,用气相色谱-质谱联用仪进行定性定量分析,双酚A的回收率在75.2%～90.7%之间、方法的检出限为5μg/kg。该方法前处理过程简单,具有较高的精密度和准确性,重复性好。     

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.     

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 m L/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。     

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。     

分子印迹固相萃取-化学发光法测定蔬菜中的马来酰肼

马来酰肼对高良姜素-高锰酸钾-多聚磷酸体系的化学发光具有增敏作用,据此结合分子印迹固相萃取技术建立测定蔬菜中马来酰肼含量的流动注射-化学发光分析方法。以马来酰肼为模板分子,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,用热聚合法合成了马来酰肼分子印迹聚合物,并以此分子印迹聚合物作为固相萃取填料制成固相萃取柱,对样品进行固相萃取后进行发光检测。在最优条件下,相对化学发光强度与马来酰肼的质量浓度在5.0×10-5～3.0×10-2mg/mL范围内呈良好的线性关系,检出限2.6×10-5mg/mL(3σ),相对标准偏差2.7%(1.0×10-3mg/mL马来酰肼,n=10)。将该法应用于马铃薯、洋葱及大蒜中马来酰肼含量的测定,加标回收率在95.2%～111.7%之间,相对标准偏差分别为1.8%、2.4%和2.1%。     

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.     

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.     

纳米金-壳聚糖/多壁碳纳米管修饰的玻碳电极检测水中微量的孔雀石绿

目的制备基于纳米金-壳聚糖/多壁碳纳米管修饰的玻碳电极,用于检测水样中微量的孔雀石绿。方法实验利用电沉积法首先在玻碳电极表面沉积金纳米颗粒,然后利用溶剂蒸发法在纳米金层表面再修饰混有壳聚糖的羧基化多壁碳纳米管。实验设计以多壁碳纳米管/纳米金共修饰的玻碳电极作为电化学传感元件,采用循环伏安法(CV)和微分脉冲伏安法(DPV)检测MG。结果表明电极的修饰膜可加速MG的电子传递速率,促进电位变化,并显著增强MG的氧化峰电流。得到的差分脉冲峰电流与孔雀石绿浓度对数值在2.5×10-9～2.5×10-4 mol/L范围内呈良好线性关系,检测限为9.3×10-10 mol/L。结论本研究制备的基于纳米金-壳聚糖/多壁碳纳米管修饰玻碳电极的电化学传感器适于孔雀石绿的快速、灵敏检测。