氢化物—原子荧光光度法测定乳粉中微量砷

本文采用氢化物－原子荧光光度法测定乳粉中砷含量。样品经硝酸和高氯酸消化后，以硫脲为预还原剂，将五价砷还原为三价砷。然后进行测定，取得满意结果。本方法具有分析速度快、灵敏度高、干扰少、重现性好、线性范围宽等优点。该方法最低检出限为０．０００３８μｇ／ｍｌ，回收率在９０￣１０９％之间，线性范围为０．００５￣０．１６μｇ／ｍｌ，其相关系数≥０．９９９６。     

还原溶出计时电位法测定食品中痕量锰

提出了在ｐＨ＝８．８的Ｈ３ＢＯ３－Ｎａ２Ｂ４Ｏ７介质中用溶出计时电位法测定食品中痕量锰的新方法。锰的检出限为０．５ｎｇ／ｍｌ,相对标准偏差≤４．８％,线性范围为０．５～２５ｎｇ／ｍｌ。采用本法对４份不同种类的食品样品进行了测定,结果与原子吸收法相符。     

催化分光光度法测定痕量钴的研究

研究了在碱性介质中，钴（Ⅱ）催化过氧化氢氧化间硝基苯基荧光酮的褪色反应及动力学条件，建立了催化动力学光度法测定痕量钴（Ⅱ）的新方法．检测限为６．５４×１０－１２ｇ／ｍｌ，线性范围为０～３．５ｎｇ／１０ｍｌ，变异系数为２．６７％．用于测定医用维生素Ｂ１２针剂中的痕量钴．     

高效液相色谱测定水果中单甲脒农药的残留

高效液相色谱分析水果中单甲脒残留的色谱条件为：ＯＤＳ柱甲醇：醋酸铵水溶液（７５：２５）为流动相，紫外检测器波长２５４ｎｍ。最小检测量为２ｎｇ，最小检出浓度为０．１μｇ／ｍｌ。平均回收率７８￣８９％，符合农药残留分析的要求。     

酶联免疫法测定牛初乳中乳铁蛋白含量

应用酶联免疫法制定牛初乳中乳铁蛋白的含量,最小检出量为０．５ｎｇ／ｍｌＬＦ,浅性范围为０．８ｎｇ／ｍｌ至１００ｎｇ／ｍｌ。标准曲线性方程为Ｙ＝－２２．７２Ｘ＋２１．３８,相关系数γ为０．９９６。结果较为理想,这种对ＬＦ的检测方法在国内未见报道。     

石墨炉原子吸收法直接测定煎炸油中的铅

本文采用皂化程序处理植物油，在碱性条件下，用二氯化钯作基体改进剂￣［１］，石墨炉原子吸收法直接测定铅含量的方法，克服了双硫腙分光光度和火焰原子吸收法测铅时，样品消化繁琐及测定灵敏度低的缺点，获得满意结果。用本方法测定时，铅含量０～２００μｇ／Ｌ范围内，浓度与峰高呈直线关系，１０次测定的回收率为９２．６％─１０８．４％，平均值为９６．４％，相对标准偏差为２．３─６．４％，平均值为４．８３％，试剂空白的标准偏差为０．００４７ｎｇ检出限为０．７μｇ／Ｌ实验表明该方法简便、快速、准确、实用性强。     

高效液相色谱示差折光法测定食品中的乳果糖

食品（本实验以强化奶粉和乳果糖浆为试验品）经称量，溶解，过滤等简单预处理，水作为流动相，在Ｂｅｃｋｍａｎ碳水化合物分离柱中分离，柱温９０℃，经示差折光检测测定量，本法的最低检测限为１０μｇ／ｍｌ（ｎ／ｓ＝３）在０．１０～１０ｍｇ／ｍｌ（绝对进样量为２～２００ｎｇ）的浓度范围内具有良好的线性关系，ｒ＝０．９９９７，精密度小于１．４２５，样品回收率在９５．５０％～９７．７０％，范围内，本方法预处理简单     

流动注射—氢化物原子吸收法测定海水中痕量铅

用ＨＣｌ－Ｋ３「Ｆｅ（ＣＮ）６」－ＮａＢＨ４体系流动注射发生Ｈ４Ｐｂ，氮气载入电热石英原子化器中原子化测定。本法具有较高的灵敏度和分析速度，用于海水中痕量铅的测定，相对标准偏差为１．７％，平均回收率为１０３％，检测限为０．３ｎｇ／ｍｌ。     

氢化物无色散原子荧光法测定罐头食品中的锡

建立了测量罐头食品中锡的氢化物－无色散原子荧光光谱法,此方法检出限为０．０２３ｍｇ／ｋｇ,相对标准偏差ＲＳＤ为４．８％,标准曲线相关系数大于０．９９９０,曲线性性范围为０～２００ｎｇ／ｍｌ,回收率为８７．５％～１０８％。     

流动注射──氢化物原子吸收法测定海水中痕量铅

用ＨＣｌ─Ｋ３［Ｆｅ（ＣＮ）６］─ＮａＢＨ４体系流动注射发生Ｈ４Ｐｂ，氮气载入电热石英原子化器中原子化测定。本法具有较高的灵敏度和分析速度，用于海水中痕量铅的测定，相对标准偏差为１．７％，平均回收率为１０３％（ｎ＝６），检测限为０．３ｎｇ／ｍｌ。     

枣中微量硒的原子荧光光谱法分析

采用原子荧光光谱法对枣中硒的含量进行分析,确定最佳测定条件。结果表明：硒的检出限为0.57ng/ml,线性范围为1.0～32.0ng/ml,回收率为99.0%～106.3%,变异系数小于1.71%。     

双道原子荧光光度计检测食品中汞元素的方法研究

目的 对食品中汞元素的含量进行测定。方法 分别采用两种不同的前处理方法提取食品中的汞, 采用AFS-8330双道原子荧光光度计进行比较。结果 线性回归方程为Y=154.4X 15.76, R2=0.9994。本方法的检出限为0.015 ng/mL, 在1.0、4.0、8.0 ng/mL三个加标水平下, 采用改良之前的方法做加标回收率实验, 平均回收率为85%, 相对标准偏差为0.6%~1.6%, 采用改良之后的方法做加标回收率实验, 平均回收率为94%, 相对标准偏差为0.9%~1.3%。结论 改进后的前处理方法提取样品时, 精密度高、准确度好、能满足食品中汞元素的定性定量分析。     

A rapid high-performance liquid chromatography with fluorescence detection method developed to analyze ochratoxin A in wine

A rapid, sensitive, reproducible, and inexpensive method of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) for the analysis of ochratoxin A (OTA) in wine was developed. It is characterized by direct injection of the wine into the HPLC apparatus, with no need of extraction or cleanup. The method uses acetonitrile, water, and acetic acid (49:49:2, vol/vol/vol, respectively) as the isocratic mobile phase and a 5-microm monolithic C18 column (100 by 3 mm inside diameter). The relative standard deviation obtained in the OTA determination varied between 0.22 and 1.76%, with a mean value of 0.89%, in samples with concentrations between 0.10 and 100 ng/ml. The recovery of OTA ranged from 102% in samples spiked with 1 ng/ml OTA to 120% in samples with 0.10 ng/ml OTA. The method compared favorably with a published method based on an immunoaffinity column cleanup and a chromatographic assay with a C18 conventional HPLC column.     

A simple HPLC method for the determination of the mycotoxins ochratoxin A and B in blood serum of swine.

This paper presents a simple method for the determination of ochratoxins A (OTA) and B (OTB) in pig blood serum. The method includes serum acidification (pH < 1.6) and precipitation of protein with 15% trichloroacetic acid, liquid partitioning with dichloromethane and fluorescence detection. The estimated detection limits were 0.1 ng OTA/ml and 0.2 ng OTB/ml. The mean recoveries from artificially contaminated samples (n = 6 replicates/mycotoxin) spiked at 0.3, 1 and 3ng OTA and OTB/ml, respectively, were 86.8% (s.d. = 8.4) for OTA and 90.0% (s.d. = 9.8) for OTB. Forty-nine Romanian pig blood serum samples (94% of 52 analysed) were found to be naturally contaminated with OTA in the range 0.1-13.4 ng/ml. No sample was found positive for OTB. The method is technically simple, specific, cost effective, suitable for large sample throughput and requires small amount of sample and reagents. It fulfils the criteria for a routine method and could be a suitable toolfor surveying OTA in pig herds and in slaughtered pigs.     

豌豆粉丝中硒含量的测定

以HNO3和H2O2溶解样品,建立了顺序注射氢化物发生-原子荧光法测定豌豆粉丝中硒的分析方法。研究了仪器条件、实验条件、微波消解方式、预还原剂等因素对硒测定的影响,探讨了共存离子的干扰及消除,确定了最佳工作条件。结果表明:方法的最低检出限为0.10ng/ml,线性范围0～80ng/ml。应用该方法测定了不同的豌豆粉丝,相对标准偏差为2.94%～4.01%,加标回收率为90.33%～102.31%。     

Absence ochratoxin A in soy sauce

A method is described for the determination of ochratoxin A (OTA) in soy sauce using phosphate-buffered saline (PBS) extraction, an immunoaffinity clean-up, a liquid chromatographic determination with fluorescence detection (LC-FD) and confirmation with LC-FD after methylation of OTA. Recoveries of OTA spiked to soy sauce samples at 0.25 ng/ml level were 90% with relative standard deviations of 4%. The limit of detection was 0.01 ng/ml for OTA using the proposed method. Furthermore, the proposed method was applied to 60 soy sauce samples from China and Japan and none of them were found to contain OTA.     

High-performance liquid chromatography multiresidue method for the determination of N-methyl carbamates in fruit and vegetable juices

A rapid multiresidue method has been developed for the analysis of N-methylcarbamate insecticides (oxamyl, methomyl, propoxur, carbofuran, carbaryl, and methiocarb) in fruit and vegetable juices. The method is based on the adsorption of the N-methyl carbamates in Florisil and the subsequent extraction of pesticides using a low volume of acetone. Residue levels in juice were determined by reversed-phase high-performance liquid chromatography with fluorescence detection after postcolumn derivatization. The separation of carbamates is performed on a C8 column with water-methanol as mobile phase. Recovery studies were performed at 500-, 100-, and 10-ng/ml fortification levels, and average recoveries obtained for carbamates ranged from 79 to 109%, with relative standard deviations between 1.4 and 9.9%. The method was found to be linear over the range assayed from 10 to 1,000 ng/ml, and the detection limits for carbamates varied from 0.8 to 1.9 ng/ml.     

Contamination of foods and feeding stuffs from selected areas of the Erfurt district with lead and cadmium. I. Determination of lead and cadmium in vegetable material by inverse voltammetry

An inverse voltammetric method is used for determining the trace elements lead and cadmium in vegetable foods and feeding stuffs. The organic meterials are mineralized by nitric acid vapour and, in the second stage, with the addition of perchloric acid. The procedure is very sensitive and suited for routine work. The detection limits are: 0.66 ng/ml for lead, and 0.30 ng/ml for cadmium. The error of the method is: VPb = 20.5% and VCd = 28.6%. The respective recoveries of amounts of lead and cadmium added to the samples prior to digestion were: 102.0 +/- 10.8% and 101.6 +/- 11.4%.     

高效液相色谱-荧光检测器测定水产品中孔雀石绿残留总量的研究

建立了水产品中孔雀石绿残留总量的液相色谱检测方法。样品中的孔雀石绿全部还原为无色孔雀石绿后,用乙腈-缓冲液提取,经净化、浓缩后,以Symmetry shieldTM RP18为固定相,以乙腈-水为流动相,使用荧光检测器检测无色孔雀石绿。无色孔雀石绿线性范围为1～160ng/ml;方法检出限为1.0μg/kg(以孔雀石绿总量计);回收率为82.6%～92.6%。     

ICP-MS测定食品中的二氧化钛

建立电感耦合等离子体质谱法（ICP-MS）检测食品中二氧化钛的含量。样品经混合酸微波消解后,用电感耦合等离子体质谱仪进行食品中二氧化钛的测定。结果表明,二氧化钛在2-1000ng/mL范围内线性关系良好,相关系数0.9995,最低检出限0.5ng/mL,平均回收率109%,平均相对标准偏差3.20%。该方法简便、快捷、有较高的灵敏度、准确度、精密度和较低的检出限,适合食品中二氧化钛的测定。