液相色谱仪测定水中苯并(α)芘方法应用

液相色谱仪测定水中苯并(α)芘方法实用性好,检测精密度高,标准偏差为0.086 3,变异系数0.87%,回收率高,平均达93.1%,而且操作简单、便于掌握。     

液相色谱仪测定水中苯并(α)芘方法应

液相色谱仪测定水中苯并（α）芘方法实用性好,检测精密度高,标准偏差为 ００８６ ３, 变异系数０８７％ ,回收率高,平均达 ９３１％ ,而且操作简单、便于掌握     

高效液相色谱法测定人参提取物中的苯并(α)芘

建立了人参提取物中苯并(α)芘残留量的高效液相色谱分析方法.样品加水浸泡,用正己烷液液萃取,提取液减压蒸干,C18色谱柱分离,以乙腈-水为流动相,外标法定量.结果表明,苯并(α)芘在1.0～ 100.0μg/L范围内线性良好,相关系数R为0.999 9,平均加标回收率为85.2％ ～ 96.7％,相对标准偏差为7.1％ ～11.2％.方法的定量限为1.0 μg/kg.该方法简单快速、灵敏度高、重现性好,能满足人参提取物中苯并(α)芘残留量定量分析的要求.     

高效液相色谱紫外荧光双检测器测定苯并(α)芘

采用紫外-荧光双检测器的高效液相色谱分别测定了不同浓度的苯并(α)芘(Ba P)标准溶液,试验结果表明:紫外检测器(VWD)对0.1~10μg/mL浓度范围的Ba P标准溶液响应较好,在该浓度范围内呈现出良好的线性关系(相关系数r=0.9999),VWD检测器7次重复试验的相对误差范围为-5.0%~2.8%,精密度为2.8%;荧光检测器(FLD)对0.001~0.1μg/mL、0.01~0.0001μg/mL浓度范围的Ba P标准溶液响应较好,在两个范围内均有良好的线性关系(相关系数r均为0.9999),FLD检测器7次重复试验的相对误差范围-5.6%~3.4%,精密度为3.2%。本试验测定中,VWD检测器的检出限为0.0053μg/mL,FLD检测器的检出限为0.00004μg/mL。     

高效液相色谱法测定空气中苯并(a)芘

用无胶玻璃纤维滤筒或玻璃纤维滤膜采样,超声波作用下以环己烷提取苯并(a)芘,提取液经KD浓缩器浓缩,配有荧光检测器的高效液相色谱仪进行测定。该法灵敏度高,再现性好,简便快速,适合于环境空气中苯并(a)芘的测定,同时也适用于污染源和水中苯并(a)芘的测定。     

对滤纸过滤法前处理水样中苯并(a)芘含量损失的研究

一般来说,地面水浊度较高,杂质较多,在分析其中苯并（a）芘含量时,如直接通过吸附柱会造成小柱堵塞,洗脱后溶液也太脏,影响高效液相色谱仪的寿命。因此,在实验室中,一般通过定性滤纸过滤作为前处理来达到去杂质的目的。但苯并（a)芘又极易吸附在杂质和滤纸上,因而滤纸过滤必将导致苯并（a）芘的检测结果偏低,也就是说,苯并（a）芘有损失。本文是通过大量实验结果来分析其损失的大小。实验表明：损失率达29．0％。     

高效液相色谱法测定废水中苯含量的不确定度评定

应用高效液相色谱法测定废水中的苯含量,预处理简单。本文对测定过程的不确定度的主要来源进行分析、评定,计算出合成不确定度。结果表明:高效液相色谱法测定废水中的苯含量,其不确定度主要来源于稀释因子和液相色谱仪,其次来源于标准样品浓度和待测样品峰响应值。     

高效液相色谱法测定水中苯并(a)芘

苯并(a)芘属于多环芳烃中毒性最大的一种强烈致癌物。为降低苯并(a)芘对土壤、空气、水等多种环境介质的不良影响,建立了液液萃取-高效液相色谱法测定水样中苯并(a)芘的分析方法。选用二氯甲烷为萃取剂,w(乙腈):w(水)=85∶15为流动相,流速1 m L/min,柱温25℃的条件下,在1 L空白水样中添加低浓度的苯并(a)芘(加标量为0.5μg),测定平行样品7份。结果表明,苯并(a)芘加标回收率为85.2%~86.6%,标准偏差为0.5%;当萃取体积为1 L,浓缩至1 m L,进样量为10μL时,苯并(a)芘的方法检出限为0.008μg/L。     

高效液相色谱法测定化妆品中苯扎氯铵含量的不确定度评定

对《化妆品安全技术规范》(2015年版)中高效液相色谱法测定苯扎氯铵3种物质(即十二烷基二甲基苄基氯化铵(C_(12))、十四烷基二甲基苄基氯化铵(C_(14))和十六烷基二甲基苄基氯化铵(C_(16))含量进行了不确定度评定,建立了数学模型,考察了不确定度的来源并给出了量化结果,计算出合成标准不确定度和扩展不确定度。结果表明,当取置信概率为95%,包含因子k=2,被测化妆品中苯扎氯铵C_(12),C_(14)和C_(16)含量分别为0.045%,0.048%和0.010%时,其标准扩展不确定度分别为0.027%,0.029%和0.006%。指出了测量不确定度的主要来源,并提出了改进方法。     

高效液相色谱法检测植物油中苯并[a]芘的含量

建立并验证高效液相色谱法检测植物油中苯并[a]芘的含量.将植物油样品溶于正己烷中混匀,用苯并[a]芘固相萃取柱净化,用正己烷洗脱苯并[a]芘,荧光检测器检测.苯并[a]芘在0.1～100μg/kg浓度范围内线性相关系数r2=0.9999,本方法平均回收率为96.95%～101.30%,相对标准偏差RsD为0.980%～...     

荧光光度法测定食用油中的苯并(a)芘

用12%(w/v)的氢氧化钾-乙醇溶液皂化食用油的脂肪酸,以环己烷萃取皂化液中的苯并(a)芘,经浓缩,柱层析纯化并浓缩,取微量试样液稀释后,以386nm为固定激发光谱,在固定发射波长406nm处测其荧光强度,继而在标准曲线上查出样品中苯并(a)芘的含量.其线性范围为0～100 ng·mL-1,平均加标回收率在88.9%～95%之间.结果表明本法具有快速、简便、准确等特点.     

Comparison of Animal and Plant DNA-Adducts after Exposure to Benzo(a)pyrene

The occurrence of abnormal hypermodified nucleotides on the DNA upon xenobiotic exposure has long been considered as a characteristic of carcinogenesis and mutagenesis in animal cells. We have previously shown that DNA adducts could also be formed in plants exposed to xenobiotics in natural and controlled conditions. In this study we have compared the DNA adducts formed in different animal species and in different plants after benzo(a)pyrene (B(a)P) exposure.

The main DNA adduct in mice stomach and skin correspond to the 7,8-diol 9,10-epoxide B(a)P-guanine. In liver from rat, fish and Xenopus, this adduct is detected, but is not the major one. In plants analyzed, this adduct is never formed. Ten different adducts are detected in plants. This result indicates that the metabolic pathway leading to genotoxic metabolites is different with species. In conclusion, the result suggest that risk assessment for human and environment due to genotoxic compounds should be realized using multiple species assays.     

Quantitative Determination of Erucic Acid in Edible Oils and Fats Containing Marine Oils and/or Hydrogenated Fats

A method has been developed for the quantitative measurement of erucic acid in complex samples of oils or fats containing marine oils and/or hydrogenated fats. A two step procedure is proposed: in a first step the constituent fatty acids of the transesterified oil or fat are resolved on a silver-nitrate-impregnated silicagel thin-layer in function of the degree of unsaturation and the double bond localization. Positional isomers migrating slowlier on the thin-layer than erucic acid (e. g. cetoleic acid often present in large amounts in marine oils) are distinctly separated in this way. In a second step components moving ahead of the cetoleic acid (e. g. erucic acid, the added internal standard and geometrical isomers of erucic acid) are scraped off from the thin-layer plate and the erucic acid is determined by gas chromatography on a packed column with a liquid crystal, operated in the nematic phase temperature region, as the stationary phase. In complex samples recoveries of 90 to 102% are reported with overall relative standard deviations of 2.5 to 3%.     

Column Chromatographic Determination of Unsaponifiable Matter in Fats and Oils

A column chromatographic method for determination of unsaponifiable matter (UM) in fats and oils has been developed. The procedure involves saponification of the oil and elution or UM through a mixed bed consisting of an upper layer of calcium oxide and a lower layer of basic aluminium oxide, using diethyl ether as the eluting solvent and finally quantitation of UM by weight. The method eliminates tedious and time-consuming extraction steps and the consequent problems due to possible emulsion by hydrolysis, UM contents of fats and oils can be determined with very good to excellent accuracy. The relative standard deviation for 6.0 per cent to 0.5 per cent of UM in oils is in the range of 0.5–2.0. The method is simple, readily adaptable, fairly rapid and is equally applicable to soap samples.     

Determination of Low Erucic Acid Levels in Oils and Fats

In view of requirements set in 1979 by the European Community regarding the reduction of erucic acid levels in foods, we developed a method by which concentrations down to 0.1% can be determined. The procedure and conclusions are discussed in brief.     

Influence of Benzo(a)pyrene on Different Epigenetic Processes

Epigenetic changes constitute one of the processes that is involved in the mechanisms of carcinogenicity. They include dysregulation of DNA methylation processes, disruption of post-translational patterns of histone modifications, and changes in the composition and/or organization of chromatin. Benzo(a)pyrene (BaP) influences DNA methylation and, depending on its concentrations, as well as the type of cell, tissue and organism it causes hypomethylation or hypermethylation. Moreover, the exposure to polyaromatic hydrocarbons (PAHs), including BaP in tobacco smoke results in an altered methylation status of the offsprings. Researches have indicated a potential relationship between toxicity of BaP and deregulation of the biotin homeostasis pathway that plays an important role in the process of carcinogenesis. Animal studies have shown that parental-induced BaP toxicity can be passed on to the F1 generation as studied on marine medaka (Oryzias melastigma), and the underlying mechanism is likely related to a disturbance in the circadian rhythm. In addition, ancestral exposure of fish to BaP may cause intergenerational osteotoxicity in non-exposed F3 offsprings. Epidemiological studies of lung cancer have indicated that exposure to BaP is associated with changes in methylation levels at 15 CpG; therefore, changes in DNA methylation may be considered as potential mediators of BaP-induced lung cancer. The mechanism of epigenetic changes induced by BaP are mainly due to the formation of CpG-BPDE adducts, between metabolite of BaP—BPDE and CpG, which leads to changes in the level of 5-methylcytosine. BaP also acts through inhibition of DNA methyltransferases activity, as well as by increasing histone deacetylases HDACs, i.e., HDAC2 and HDAC3 activity. The aim of this review is to discuss the mechanism of the epigenetic action of BaP on the basis of the latest publications.