Application of HPLC for the Determination of PSP Toxins in Shellfish

A high performance liquid chromatographic (HPLC) procedure for determination of the toxins associated with paralytic shellfish poisoning (PSP) is compared to the standard AOAC mouse bioassay method on 100 shellfish samples representing a variety of species. For those samples with toxin content below the detection limit of the bioassay (35 μg saxitoxin (STX)/100g) HPLC analysis indicated a similar low level with a range of <10 to 56 μg STX/100g (n = 60). A correlation coefficient of 0.92 was determined for the 40 samples exhibiting toxicity in the bioassay (i.e., >35 μg STX/100g). Among the advantages of the HPLC method over the bioassay are significantly better sensitivity, greater sample through-put, and ability to determine the levels of each individual PSP toxin.     

Semiautomated Method for the Analysis of PSP Toxins in Shellfish

The method uses an autoanalyzer continuous flow reaction system to oxidize toxin in standard acid extracts of shellfish, prepared for mouse bioassay, to derivatives which are detected by fluorescence. Oxidation is by periodic acid under alkaline (NH₄OH) conditions and is followed by acidification by acetic acid. Concentrations of 10 μg/100g toxin and above can be measured with good reproducibility and accuracy: coefficient of variation was 9.5% for samples with 60 μg/100g or greater. Correlation with the mouse bioassay was 0.82 for 204 samples (toxin from 0–2000 μg/100g). The method is proposed to screen shellfish samples for PSP toxins with only samples falling into the range 60–250 μg/100g being subject to the more tedious and expensive mouse bioassay.     

小鼠法检测脂溶性贝类毒素假阳性来源分析

目的：探讨牡蛎样品中游离脂肪酸含量随贮存温度和时间的变化,以期对小鼠法检测脂溶性贝类毒素假阳性结果的来源进行探索和分析。方法：采用三氟化硼甲酯化法对脂肪酸进行衍生化,使用固定液100%二氰丙基聚硅氧烷的毛细管色谱柱对牡蛎样品中游离脂肪酸进行检测。结果：－10 ℃和－20 ℃贮存样品中游离脂肪酸总含量随时间延长先增加后减少,之后再缓慢增加,4 ℃贮存样品中游离脂肪酸总含量随贮存时间的延长一直缓慢增加;贮存时间相同,－20 ℃贮存样品游离脂肪酸含量明显高于－10 ℃。在3 种贮存温度条件下,高毒游离脂肪酸C20∶5n-3和低毒游离脂肪酸C22∶6n-3含量均随时间延长而增长。5 个月后－20 ℃贮存样品中C20∶5n-3含量为136.79 μg/g,达到小鼠最小致死量（6 mg）45%;若取2.5 倍称样量进行实验,可导致小鼠法假阳性结果。结论：牡蛎样品中高毒游离脂肪酸是小鼠法检测脂溶性贝类毒素假阳性结果的重要来源,且高毒游离脂肪酸含量随贮存温度和时间变化呈增长趋势。     

生物传感器在贝毒快速检测中的应用

贝类毒素是继病原菌、弧菌和病毒之后,又一威胁海洋水产品质量的重要问题。随着水产品的安全性越来越受到关注,生物传感器作为一种新的分析工具,在水产品贝类毒素检测中具有广泛应用价值。文中简单介绍了贝类毒素和生物传感器及它们的特点,重点回顾了近年来生物传感器在贝毒快速检测中的应用。     

Comparison of Four Methods for Determining Protease Activity in Milk

Four methods (absorbance at 280 nm; the Lowry method; the fluor-escamine method, and the trinitrobenzenesulfonic acid method) for determining hydrolysis of milk proteins were compared. Each method was applied to the trichloracetic acid soluble fraction of milk protein, which had been digested with trypsin for various periods of time. Detectability was measured as the ratio between standard error of estimate and slope calculated from the linear regression analysis of Deming for cases when both variables were subject to error. Although it was nondimensional, the detectability thus calculated was simple and reliable for comparing assay methods which were based on different analytical principles. Detectability as well as the detection limit measured according to Schwerdtfeger showed that, of the methods compared, the fluorescamine method was most reliable and sensitive.     

Determination of Paralytic Shellfish Poisoning (PSP) toxins in dietary supplements by application of a new HPLC/FD method

Over the past years the importance of food additives and the development of so-called novel food increased permanently. Especially, the application of dietary supplements was on the rise. Then, more and more new products based on plants hitherto not used for human consumption were launched. Algae products containing valuable amounts of essential nutrients such as amino acids and trace elements play a decisive role. On the other hand, some algae including the blue-green algae (cyanobacteria) are capable of synthesizing harmful substances depending on species and provenience. Therefore, methods must be available to evaluate possible risks caused by toxins in algae-based dietary supplements. There are different groups of toxins related to marine algae and cyanobacteria. However, both marine algae and cyanobacteria are able to produce Paralytic Shellfish Poisoning (PSP) toxins which are potential neurotoxins. Hence, analytical methods for PSP determination have to be developed. The method for PSP toxin determination described below is based on ion-pair chromatography of the underivatized PSP toxins followed by post-column oxidation and fluorescence detection (FD). The determination of very low amounts of PSP toxins in different matrices of novel food is possible. In addition, the method allows to compare PSP profiles of various algae-based dietary supplements.     

桑沟湾养殖牡蛎中贝类毒素监测及预警

利用高效液相色谱-串联质谱(high performance liquid chromatography-tandem mass spectrometry,HPLCMS/MS)方法监测养殖牡蛎中5种腹泻性贝类毒素与6种麻痹性贝类毒素含量变化及分布特征,分别利用HP20大孔型吸附树脂与SP700吸附树脂作为富集树脂,富集养殖海域海水中5种腹泻性贝类毒素与6种麻痹性贝类毒素,利用HPLC-MS/MS检测方法分析其中毒素含量,同步监测了养殖海域内牡蛎与海水中毒素含量,探究了两者之间的关系,建立了牡蛎内贝类毒素含量随海水内贝类毒素含量之间的变化规律。结果显示:在该海域内一共监测到OA、DTX-1、GYM、PTX-2 4种腹泻性贝类毒素与STX、dc STX两种麻痹性贝类毒素;在整个监控期内,海水中所监测贝类毒素随时间变化呈现先增长,达到峰值后逐渐降低趋势。牡蛎中毒素含量与海水中毒素含量呈正相关关系,即牡蛎内毒素的增长随海水内毒素的增长而增长,但牡蛎内毒素含量的峰值出现时间在海水中毒素含量出现峰值之后,延后时间为14 d。根据固相吸附毒素跟踪技术原理,可以提前14 d预警牡蛎内毒素含量。     

A Comparison of Available Methods for Determining Salt Levels in Cheese

Comparative salt analyses were run on seven different types of cheese using each of four methods: Mohr, Volhard, ion selective electrode, and chloride analyzer. The results of Volhard, Mohr, and chloride analyzer methods were similar for unaged cheese varieties, i.e., Mozzarella, Cheddar, Ricotta, Romano, and Provolone, but concentrations detected with the ion selective electrode were lower than the other three methods. Results were similar with aged Cheddar and process cheeses except the Mohr procedure proved unreliable. A constant correction factor could be used to make the ion selective electrode results similar to that obtained with the Volhard procedure.     

9种腹泻性贝类毒素的高效液相色谱-串联质谱测定方法的建立

建立一种同时测定贝类产品中9种腹泻性贝类毒素的高效液相色谱-串联质谱（HPLC-MS/MS）方法。本文通过优化色谱条件、质谱条件、前处理等步骤,最终确定以80%乙腈水溶液对样品进行提取,利用QuEChERS和分散固相萃取技术进行净化,以C₁₈色谱柱进行分离,5 mmoL/L乙酸铵（加0.1%甲酸）缓冲液和乙腈为流动相进行梯度洗脱,质谱采用多反应监测模式（MRM）,外标法定量。9种腹泻性贝类毒素在质量浓度0.5～50 ng/mL的范围内线性关系良好,其线性相关系数均在0.996以上,检出限为1～10 μg/kg,回收率为87.2%～111.2%,相对偏差（n=6）为2.8%～9.2%。结果表明,该方法前处理简便快捷,准确性高、灵敏度较高、重现性好,而且节约成本,适合大批量检验,满足实际检测要求。     

Comparison of HPLC and GC Methods for Measuring Lactic Acid in Ground Beef

A rapid method for measurement of lactic acid in refrigerated ground beef was developed using high performance liquid chromatography (HPLC) with an Aminex HPX-87H ion exclusion column. The method was compared with an existing gas chromatography procedure. Nine samples of ground beef, consisting of three grades based on fat content, were tested over six days of aerobic and two weeks of anaerobic storage. No significant difference was found in reproducibility between the two methods as measured by their variance. There also was no significant difference between the variances for grade of beef or for duration of aerobic or anaerobic storage. The following equation was developed to relate the two methods: GC =−138.43 + 1.1254 (HPLC).     

海地瓜多糖中蛋白含量测定方法比较

比较4种常用的蛋白定量方法来测定海参多糖中蛋白含量,建立海参多糖中蛋白含量的测定方法。氨基酸组成折算出海地瓜多糖中蛋白含量为(5.06±0.31)%,将此结果作为其他测定方法比较的标准。采用4种常用的蛋白定量方法:Folin-酚法、BCA法、考马斯亮蓝法、荧光光度法进行测定,对测定结果进行比较分析。Folin-酚法、BCA法、荧光光度法测定多糖中蛋白含量分别为(4.92±0.20)%、(6.29±0.51)%、(3.88±0.25)%。考马斯亮蓝在反应中不显色,此法检测不出多糖中蛋白。经比较分析,Folin-酚法精确度高,重现性好,测定时间短,操作简便,对仪器要求低,可以准确简便地测定海地瓜多糖中蛋白含量。     

Comparison of Spectrophotometric and HPLC Methods to Quantify Betacyanins

Quantitative data for betacyanins determined by a spectrophotometric method and a high performance liquid chromatography (HPLC) method were compared. Pigment solutions at pH 4.0, 5.0 and 6.0 were heat treated under a nitrogen atmosphere and analyzed for pigment losses at appropriate intervals. Fresh, blanched and canned beets were measured for pigment content by the two methods. Quantitative determinations of pigment in all purified or undegraded samples compared well when analyzed by either method. Discrepancies between results of the two procedures occurred and increased up to 15% with extended heat treatment of the pigment. The differences were: attributed to formation of degradation products or interfering substances. Of the two, the HPLC method is preferred when interfering substances are present.     

食品中微生物源毒素检测方法研究进展

食品中的微生物源毒素是指由微生物代谢产生的毒素,主要包括肽类毒素、脂多糖内毒素、霉菌毒素、生物胺和脂肪酸氧化产生的醛类化合物等。通过介绍国内外学者对这几种毒素的检测方法,在对聚合酶链反应技术、酶联免疫检测技术、高效液相色谱法、固相微萃取-气相色谱-质谱法和固相微萃取-气相色谱-嗅觉法等检测方法综合分析的基础上,评述上述方法的特点和适用条件,并总结食品中的微生物源毒素检测技术的研究进展。     

油菜蜂花粉蛋白水解度测定方法比较

采用Alcalase 2.4L FG 水解油菜蜂花粉蛋白,比较pH stat 法、OPA 法和TNBS 法测定蜂花粉蛋白水解度的差异。水解118min 后,pH stat 法、OPA 法和TNBS 法测得的水解度分别为24.7% ﹑ 13.4% ﹑ 6.6%。由于OPA试剂和甘氨酸﹑半胱氨酸﹑赖氨酸反应生成的化合物在340nm 波长处的吸光度较低,致使OPA 法测得的水解度低。TNBS 试剂和ε-NH2 的作用不稳定,也可能是由于TNBS 试剂产生的发光物使测定结果降低。在水解度较低的情况下,α-NH2 平均解离度的变化可以忽略,pH stat 法测得的水解度比较准确。     

不同方法处理的浒苔的小鼠体内抗氧化活性比较

本研究比较了三种不同方法处理的浒苔在小鼠体内的抗氧化作用,在衰老模型小鼠灌胃给予浒苔原粉(EO),浒苔多糖(EP),浒苔超声处理粉末(EU-L)低剂量,浒苔超声处理粉末(EU-H)高剂量分别为300 mg/kg·d,100 mg/kg·d,300 mg/kg·d,350 mg/kg·d,7周后检测其对小鼠血清、肝脏、脑组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、过氧化氢酶(CAT)含量的影响。结果表明,浒苔产品对小鼠体重增长无影响;其中,血清中CAT含量由模型组的6.90U/m L提高到EP组8.79U/m L,EU-L组8.31 U/mL,EU-H组9.43 U/mL,与模型组对照差异极显著(p0.01),EU-H组小鼠血清、肝和脑组织的SOD、GSH-Px、CAT含量均显著高于模型组(p0.01);给予浒苔产品的四组小鼠MDA含量均低于模型组9.94U/m L,7.88U/mg prot,6.63U/mg prot(p0.05)。说明,浒苔超声粉高剂量组(EU-H)能够有效提高衰老模型小鼠体内抗氧化酶活性,对衰老小鼠的治愈率达90%以上,效果优于浒苔多糖(EP);而且根据剂量比较,浒苔超声粉(EU)可以剂量依赖性地提高衰老小鼠体内抗氧化能力。     

小麦粉中过氧化苯甲酰的色谱测定法的比较与改进

本文通过采用高效液相色谱法与气相色谱法分别测定小麦粉中的过氧化苯甲酰,并对检测结果进行比较,发现两种检测方法的结果均令人满意,且两法的检测结果不存在显著性差异。但相对而言,气相色谱法操作较繁琐,耗时较长,适合于少量样品的检测,而高效液相色谱法操作较简便、快捷,更适合于大批量样品的检测。     

生物素测定方法的分析

生物素是一种B族维生素。近几年,生物素受到了广泛的关注,与此同时,生物素测定方法的研究也取得了迅速的发展。文中介绍了近年来生物素测定常用的几种方法,包括微生物法、高压液相色谱法、生物传感器法、毛细管电泳法、荧光法、ELISA法、微分脉冲伏安法,并简单介绍了生物素分析的研究现状与进展。     

QuEChERS净化技术结合高效液相色谱-串联质谱法测定食用贝类产品中4种脂溶性贝类毒素

建立了QuEChERS净化技术结合高效液相色谱-串联质谱法测定食用贝类产品中4种脂溶性贝类毒素(OA,SPX1,DTX1,AZA1)的快速方法。贝类样品匀质后用85%乙腈水萃取,采用QuEChERS净化技术对其进行富集净化后,用HPLC-MS/MS进行检测。以乙腈-水溶液(2 mmo/L乙酸铵,0.1%甲酸)为流动相进行梯度洗脱,经C18色谱柱分离,在多反应监测(MRM)模式下扫描。采用标准曲线外标法定量,OA和DTX1的方法检出限为10μg/kg,在1.0~100μg/L范围内线性关系良好;AZA1和SPX1的方法检出限为1.0μg/kg,在1.0~20μg/L范围内线性关系良好,相关系数(r2)均大于0.999。高、中、低三个添加水平的平均回收率在81.9%~93.1%之间,RSD小于5%。应用该方法对进出口的贻贝、北极贝、象拔蚌、牡蛎等15个样品进行检测,发现5个样品的SPX1测定结果为阳性。该方法操作简便、灵敏度高、重现性好,适用于贝类产品中脂溶性贝类毒素的检测。     

鹅膏肽类毒素检测方法的历史与现状

每年因误食毒蘑菇导致中毒死亡事件在世界各国都有发生,也是我国食物中毒事件中导致死亡的重要因素 之一。鹅膏菌属中某些种类含有的肽类毒素是主要的致死原因,快速而有效地检测样品（包括有毒蘑菇子实体、食 物剩余物、呕吐物、中毒患者血液和尿液等）中的毒素对于食物中毒的毒源鉴定和中毒后的针对性治疗具有重要意 义。本文从化学显色反应、生物化学法、物理法、色谱法等4 个方面对鹅膏肽类毒素检测方法的历史和研究进展进 行整理和总结,并对其在我国的应用加以讨论和展望。