石墨炉原子吸收法快速测定血铅的研究（20130204修改稿）

摘 要：建立一种新的石墨炉原子吸收法测定血铅的快速方法。本文采用含40 ml/ L硝酸与6 ml/ L过氧化氢的混合提取液,脱去全血中的蛋白,以硝酸钯（1g/L）为基体改进剂,石墨炉原子吸收光谱法直接上机测定。方法的线性范围为0~100 µg/ L,最低检出限为4 µg/ L,加标回收率为88.1 %～110.3 %,相对标准偏差为(RSD)为3.4 %～9.1 %。方法已成功应用于全血样品的铅测定,结果令人满意. 关键词：石墨炉原子吸收法;全血;铅     

石墨炉原子吸收法快速测定血铅的研究

目的 建立一种新的石墨炉原子吸收法测定血铅的快速方法.方法 采用含40 ml/L硝酸与6 ml/L过氧化氢的混合提取液,脱去全血中的蛋白,以硝酸钯(1 g/L)为基体改进剂,石墨炉原子吸收光谱法直接上机测定.结果 线性范围0～ l00μg/L,最低检出限4μg/L,加标回收率88.1％～ 110.3％,相对标准偏差为(RSD) 3.4％ ～9.1％.结论 该方法已成功应用于全血样品的铅测定,结果满意.     

食品中痕量碘的发光分析

研究了高锰酸钾-I-甲醛体系化学发光,从而建立了一种测定微量碘的新方法。讨论了各种反应物浓度、酸度、干扰离子等因素对测定结果的影响。I-浓度在1.0×10-6～4.0×10-5g/ml范围内与化学发光强度有较好的线性关系,对1.0×10-5g/ml的I进行了11次平行测定,相对标准偏差为2.8%,方法的检出限为2.4×10-8g/ml。结果令人满意。     

KMnO4-I--H2CO体系化学发光法测定食品中的微量碘

研究了KMnO4-I--H2CO体系化学发光,从而建立了一种测定食品中微量碘的新方法。讨论了各种反应物浓度、酸度、干扰离子等因素对测定结果的影响。I-浓度在1.0×10-6～4.0×10-5g/ml范围内与化学发光强度有较好的线性关系。对1.0×10-5g/ml的I-进行了11次平行测定,相对标准偏差为2.8%,方法的检出限为2.4×10-8g/ml,结果令人满意。     

微波溶样——石墨炉原子吸收法测定鸡蛋中的铬

测定食品中微量铬时,传统的预处理方法有干法灰化和硫酸--过氧化氢氧化法[1],前者炭化时间长,耗时耗电,后者需大量试剂,产生的酸雾污染环境,且少量的油脂不易被消化完全.本文利用微波消解鸡蛋,并对几种处理方法造成的结果差异进行了比较,发现利用微波技术消化样品简单快速、省试剂、少污染.利用石墨炉原子吸收法测铬,检出限7.9×10-11g/ml,相对标准偏差2.3%(n=10),回收率96.0%～101.0%,结果满意.     

流动注射化学发光法测定谷氨酸的研究

在碱性条件下,NBS氧化谷氨酸产生强烈的化学发光信号,结合流动注射技术,建立了测定味精中谷氨酸含量的流动注射化学发光分析法。实验研究了影响化学发光信号强度的各种因素,方法的测定线性范围为3.0×10-6～1.0×10-3g/mL,检出限(3σ)为1×10-6g/mL。对1.0×10-5g/mL的谷氨酸进行11次平行测定,相对标准偏差为3.1%。将该法用于味精产品中谷氨酸的含量分析,结果令人满意。     

石墨炉原子吸收分光光度法测定黄豆及腐竹中的硼

目的 建立测定黄豆及腐竹中硼含童的石墨炉原子吸收分光光度法.方法 样品经过HNO_3 + H_2O_2微波消解或加入饱和的Ca(OH)_2助灰化剂干灰化后,选择硝酸钙(10 m/ml)-硝酸铵(20 mg/ml)-柠稼酸(20mg/ml)的混合液作为化学改进剂,采用热解涂层石墨炉原子吸收分光光度法进行测定.结果 硼含量在0～1μg/ml的线性范围内呈线性关系,相关系数r=0.9996,检出限0.017 09μg/ml;方法的精密度(RSD,n=6)为3.56% ～6.45%,回收率为87.20% ～93.70% o结论建立的方法操作简便易行,重现性、灵敏度和准确性能满足分析要求,适用于黄豆及腐竹中硼含量的测定.     

流动注射化学发光法测定食品营养添加剂中铅

研究了表面活性剂对痕量Pb(Ⅱ)催化H2O2氧化鲁米诺—邻菲啰啉化学发光反应的影响酝挛拢?0为增敏剂,建立了增敏反应化学发光测定痕量铅的新体系。本方法线性范围(1×10-6～1×10-4mg/ml)宽,检出限(2.5×10-7mg/ml)低, pH范围拓宽由原来的3改变成3～8。可用于食品营养添加剂——丙酸钙、乳酸钙、醋酸钙和卵黄高磷蛋白中铅的测定,结果良好。     

石墨炉原子吸收光谱法和胶体金快速定量法测定粮食中铅的对比研究

通过对石墨炉原子吸收光谱法和胶体金快速定量法测定粮食中铅的检出限、定量限、准确性、重复性、检测时长和适用性等参数进行测试,为粮食中铅的检测方法的选择提供了实验依据。结果表明,不同粮食作物检出限不同,小麦的检出限最低,玉米次之,大米最高,两种方法的检出限和定量限均满足粮食中铅测定的质量控制要求且石墨炉原子吸收光谱法的检出限更低;对大米/糙米、小麦和玉米不同浓度的阳性样品进行检测,两种方法的测定结果无显著性差异;对大米/糙米、小麦和玉米中铅的重复性试验,两种方法的精密度均满足国标检测要求;单个样品的检测时长,从称量到读取数据石墨炉原子吸收光谱法需要12 h,而胶体金快速定量法仅需35 min即可完成。     

固相萃取柱脱盐-石墨炉原子吸收法测定酱油中铅

目的 建立固相萃取柱脱盐—石墨炉原子吸收法测定酱油中铅的方法.方法 酱油经微波消解后,消解液用乙酸铵调节至pH≈5.5,过经用5 ml 1 mol/L乙酸铵活化后的DigiSEP-Blue柱,将被测元素铅吸附与基体中高盐分离,再分别用8 ml 2 mol/L硝酸、2 ml纯水洗脱,应用石墨炉原子吸收法测定洗脱液中铅含量.结果 用固相萃取柱可将酱油中98％以上的钠盐与被测元素铅分离,消除了石墨炉原子吸收分光光度计测定铅时的基体干扰.低、高两个铅浓度(10和30 ng/ml)的加标平均回收率(n=7)分别为91.3％ ～95.1％,97.9％～98.6％,相对标准偏差为2.1％ ～7.0％,检出限为1.33 ng/g.结论方法准确、灵敏度高,适于高盐样品酱油中铅含量的测定.     

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。     

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 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.     

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.     

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。     

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。     

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。     

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。