醛类-DNA 加合物检测技术研究进展

甲醛、乙醛、丙烯醛和巴豆醛广泛存在于环境污染物中,卷烟烟气中也有微量存在,它们不需要经过机体代谢就能够直接进攻亲核基团,可与 DNA分子发生共价结合形成 DNA加合物。DNA加合物是 DNA损伤的一种形式,在 DNA复制过程中可使所携带的遗传信息发生改变,从而有可能造成机体的损伤。本文综述了生物体内常见的 6种醛类-DNA加合物的检测技术以及醛类-DNA加合物作为卷烟烟气暴露的生物标志物的研究进展,展望了同时检测多种 DNA加合物的研究方向及醛类-DNA加合物作为 DNA损伤标志物的研究前景。      

基于仿生学的未来食品工业展望

动脉粥样硬化是由内皮细胞的损伤、脂质沉积等引起的慢性炎症反应性病理过程。Omega-3多不饱和脂肪酸(n-3 PUFA)具有重要的动脉粥样硬化保护作用,但其机制仍不明确。多不饱和脂肪酸在环氧化酶、脂氧合酶和细胞色素P450氧化酶的作用下产生具有不同生物活性的类二十烷酸代谢产物。Omega-3多不饱和脂肪酸在自身被代谢为类二十烷酸的同时,也可与花生四烯酸竞争共同的代谢酶,从而也对花生四烯酸来源的类二十烷酸代谢产物水平起调控作用。文章基于代谢的观点,系统地讨论了Omega-3多不饱和脂肪酸通过影响类二十烷酸代谢谱而发挥动脉粥样硬化拮抗作用的机制。     

噁唑烷类化合物在制革上的应用现状及前景

综述了铬鞣及无铬鞣现状;分析了这两类鞣法存在的主要问题及解决问题的方向。介绍了噁唑烷类化合物的性质及应用现状;讨论了噁唑烷类化合物及其改性产物用于制革尤其是无铬鞣的前景。     

烷醇酰胺结合型加脂剂的制备

烷醇酰胺结合型加脂剂是一种具有良好柔软作用的皮革加脂材料。本文阐述了目前制备烷醇酰胺结合型加脂剂过程中的酰胺化、酯化及亚硫酸化等反应的过程与特点,重点综述了该类加脂剂制造原料、条件与产物形成之间的关联。     

延边地区烤烟主要化学成分与中性香气物质的关系

采用随机取样方法研究了延边地区烤烟化学成分与中性香气物质含量的关系。结果表明,还原糖和烟碱与各类香气物质总量相关性不显著;总氮与苯丙氨酸类、棕色化产物类、新植二烯含量及香气物质总量呈显著或极显著正相关,与苯丙氨酸类和棕色化产物呈显著二次曲线相关关系;蛋白质与除类西柏烷类以外的香气物质及总量呈显著或极显著正相关,与各类香气含量及总量呈显著或极显著二次曲线关系;钾与类胡萝卜类和类西柏烷类呈极显著正相关,且呈显著或极显著二次曲线相关关系;在总氮1.06%~1.99%、蛋白质3.45%~10.18%和钾0.66%~1.94%含量范围内,相对提高其含量,有利于烤烟香气物质含量的提高。     

摘除下部不适用烟叶对烤烟中性致香物质含量的影响

为了明确重庆烟区不同鲜烟叶处理技术对烤烟中性香气物质含量的影响,以云烟97为材料,研究了摘除下部烟叶（0、2、3和4片）对烤烟中性香气物质的影响。结果表明,摘除2片能显著提高上部叶的类胡萝卜素降解产物和新植二烯的含量,但也显著降低了中部叶的苯丙氨酸类、类西柏烷降解产物和类胡萝卜素降解产物含量;摘除3片能显著提高中部叶的苯丙氨酸类、类胡萝卜素降解产物和新植二烯含量,同时对上部叶的苯丙氨酸类、棕色化产物类和类西柏烷降解产物含量的提高有显著的促进作用,但也显著降低了中部叶棕色化产物含量;摘除4片显著提高了中部叶棕色化产物和类西柏烷降解产物的含量,但显著降低了上部叶的苯丙氨酸类和类胡萝卜素降解产物含量。致香物质总量显示,不同处理间存在极显著差异,其中,中部叶以摘除3片含量最高,摘除4片次之,对照最低;上部叶含量依次为摘除2片 > 摘除3片 > 对照 > 摘除4片。因此认为,在该生态条件下摘除下部鲜烟叶时以3片为宜。     

茶叶有效成分与核酸相互作用的研究进展

本文讨论了茶提取物和儿茶素与核酸的相互作用，已有的研究结果表明儿茶素能够清除自由基，诱导癌细胞凋亡阻止DNA的交联及DNA加成物的形成，还能抑制肿瘤细胞DNA的合成，诱导癌基因表达下调，降低细胞微孩率，更重要的是茶提取物能保持：DNA不受辐照损伤，抑制G—C、G—A颠换．修复自由基诱导生成dGMP加合物。     

天然色素虾青素的功能性研究进展

虾青素属于类胡萝卜素中的叶黄素类,是许多微藻、酵母和细菌合成的次级代谢产物。因其独特的化学结构,虾青素已被列为多种急性或慢性疾病的最佳预防和治疗药剂。该综述根据目前研究动态,总结了虾青素在多种生物活性中的现有数据,包括抗氧化、调节炎症与动脉粥样硬化、皮肤损伤、神经变性、肿瘤以及免疫活性,改善认知功能,修复DNA损伤,以期为虾青素的功能性研究提供理论指导。     

烤烟香型间致香物质组成比例及其差异分析

以2009年收集的84份C3F烟样为材料,研究了浓香型、清香型和中间香型烟叶致香物质组成比例及其差异。结果表明:清香型烟叶中棕色化反应降解产物极显著高于其他香型,新植二烯显著或极显著低于其他香型,中间香型烟叶中苯丙氨酸类降解产物、类西柏烷类降解产物的组成比例极显著低于其他香型。     

辣椒碱对生物大分子氧化损伤的保护作用

本文分别采用Cu~(2+)/H_2O_2、AAPH体系诱导BSA氧化和羰基化损伤、Hemin/nitrite/H_2O_2诱导BSA硝基化损伤;Fe~(2+)/Vitc、AMVN诱导亚油酸(LA)过氧化及AAPH诱导鲱鱼精DNA氧化损伤的模型,研究了辣椒碱对生物大分子在羟自由基和烷氧自由基攻击下发生氧化损伤的保护作用。结果表明:50μM~1000μM的辣椒碱能显著抑制自由基诱导的蛋白质氧化损伤;10μM~1000μM的辣椒碱能显著抑制羟自由基诱导的蛋白羰基化、蛋白氧化应激产生的硝基化以及脂质过氧化终产物TBARS的生成,100μM~1000μM的辣椒碱能显著抑制烷氧自由基诱导的蛋白羰基化和DNA的氧化损伤。得出结论:辣椒碱对不同自由基诱导的生物大分子氧化损伤有显著的保护作用,且其保护作用在一定浓度范围内与辣椒碱浓度呈正相关。本研究为辣椒碱在食品抗氧化剂以及功能食品中的开发与应用提供了基础依据。     

A review of methodology for the analysis of pyrethrin and pyrethroid residues in food of animal origin

Pyrethrin and pyrethroid pesticides are commonly used in crop protection and animal health, to control pests. As a result, they can potentially transfer into food if good agricultural practice is not followed or even due to accidental contamination. The analysis of these compounds has been widely reported in crops and the environment. However, the analysis of pyrethrin and pyrethroids has not been reported frequently in foods of animal origin, particularly animal tissues. The focus of this review is to report on pyrethrin and pyrethroid analysis including key aspects such as chemistry, choice of target matrix, sample preparation, chemical analysis, legislation and method validation. This review shows that most methodologies for the analysis of these compounds are based on gas chromatography with the trend in recent years to move towards GC-MS or GC-MS/MS based platforms. This review shows that these compounds can also be satisfactorily analysed by LC-MS/MS, which can be advantageous because of shorter chromatographic run times. A wide range of sample preparation procedures have been applied in analytical methods and more complex protocols are required for GC applications, whereas more crudely prepared extracts can be analysed by LC-MS/MS. This review demonstrates that pyrethrin and pyrethroid residues should be included as analytes in multi-class analytical methods for pesticides and veterinary drug residues in animal derived foods.     

蜂毒肽的分离纯化及结构鉴定

目的 对蜂毒肽进行分离纯化,并进行结构鉴定。方法 以意大利蜜蜂蜂毒为原料,经溶解、超声、浸提、过滤等,并制备C18液相色谱柱,对一次纯化采用的流动相、洗脱程序进行优化,对二次纯化时进样量、进样浓度进行选择,冻干后得到高纯度蜂毒肽。利用基质辅助激光解析电离飞行时间质谱法(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)和液相色谱-串联质谱法(liquid chromatography-tandem mass spectrometry, LC-MS/MS)进行分子量测定等定性研究,利用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)进行二级结构表征,尝试利用低场核磁共振(nuclear magnetic resonance, NMR)技术对其氢谱定性解析,基于高效液相色谱法(high performance liquid chromatography, HPLC)的面积归一化法测定蜂毒肽纯度。结果...     

酶联免疫法与液相色谱-串联质谱法检测猪肉中沙丁胺醇

运用酶联免疫法（ELISA）与液相色谱-串联质谱法（LC-MS/MS）对猪肉中沙丁胺醇残留进行测定,并比较了二者在灵敏度、准确性和重现性等方面的差异。结果显示,ELISA法和LC-MS/MS法在猪肉样品中的检测限可达到0.5 μg/kg和0.25 μg/kg,分别向猪肉样品中添加3个质量浓度水平（1.0 μg/kg、2.0 μg/kg、4.0 μg/kg）的沙丁胺醇时,回收率分别为83.7%～90.9%和86.6%～93.5%,变异系数（CV）分别为5.4%～10.3%和6.0%～8.3%。用酶联免疫法实际样品进行检测,筛选出2个阳性样品,经液相色谱-串联质谱法确证亦为阳性,测定结果一致。研究表明,酶联免疫法重复性较好、准确度较高,适用于进行猪肉样品中沙丁胺醇的快速筛选,液相色谱-串联质谱法适用于阳性样品的确证和精确定量。     

Pesticide and veterinary drug residues in honey - validation of methods and a survey of organic and conventional honeys from Slovenia

ABSTRACT

Four analytical methods were developed and validated for the determination of veterinary drug residues and environmental pesticide residues in honey: (a) GC-MS method for the analysis of amitraz and all metabolites containing the 2,4-dimethylaniline moiety; (b) GC-MS method for the analysis of thymol, chlorfenvinphos and coumaphos; (c) GC-MS method for the analysis of 75 active substances; (d) LC-MS/MS method for the analysis of 60 active substances. Between the GC-MS (method c) and the LC-MS/MS method (method d) there was no overlap among active substances, meaning that using both methods 135 active substances originating from the environment in total were included and validated. The first method involved hydrolysis of amitraz and its metabolites containing the 2,4-dimethylaniline moiety to 2,4-dimethylaniline and extraction of 2,4-dimethylaniline to n-hexane. The other three methods had the same extraction procedure with a mixture of solvents: acetone, dichloromethane and petroleum ether. All 4 methods were tested in practice. Sixty samples of honey were analysed: 22 from organic and 38 from conventional production. Overall, residues were mainly higher than reported in literature but did not exceed MRLs. Risk assessment confirmed that the analysed samples are of no cause for concern for consumers.     

Development and validation of multi-residue method for determination of 412 pesticide residues in cotton fiber using GC-MS/MS and LC-MS/MS

The new global concept is to care about textiles and clothes safety to improve the protection of the human health and the environment from the harmful pesticide residues. Very few articles have been published for determination of several pesticide classes in cotton fibers in one multi-residue method. A simple, efficient, sensitive, accurate, and reliable multi-residue method was developed for the determination of 412 residual pesticides in cotton fibers using modified QuEChERS method with Liquid and Gas Chromatography coupled to Triple Quadrupole Mass Spectrometer (LC-MS/MS &; GC-MS/MS) for qualitative and quantitative analysis according to the international standards concepts. The developed method covered several pesticide classes, including 43 carbamates, 16 pyrethroids, 27 organochlorines (OCs), 54 organophosphorus (Ops), 31 urea derivatives, 7 Polychlorinated biphenyl (PCBs), 6 Neonicotinoid, and 228 other pesticides. Most of the target pesticides were listed in Oeko-Tex Standards, the EU Ecolabel for textile products, and the Egyptian recommendations of the Agricultural Pesticide Committee (APC-Egypt). The method optimization and validation were carried out according to the EU guidelines. The results were shown to be reliable where the corresponding average recoveries within the acceptable range of 70–120%; the relative standard deviations were less than 20%. The limit of quantitation (LOQ) of this method is 0.01 mg kg^?1 all pesticides except for 3 GC-compounds and 19 LC-compounds which have LOQ of 0.05 mg kg^?1.     

GC-MS和LC-MS/MS分析麦粉中烷基间苯二酚同系物组成

建立气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）联用法和液相色谱-串联质谱（liquid chromatography-tandem mass spectrometry,LC-MS/MS）法测定麦粉中烷基间苯二酚组成。样品经乙酸乙酯超声提取,在GC-MS中,硅烷化衍生处理,采用选择离子监测模式进行测定,以外标法进行定量;在LC-MS/MS中,经固相萃取富集净化,以C18色谱柱分离,采用电喷雾负离子模式扫描、多反应监测模式检测,以外标法进行定量。结果表明,GC-MS和LC-MS/MS均在0.001～5 μg/mL质量浓度范围内有良好的线性关系（R2＞0.98）,GC-MS法的检出限为2.0～6.1 μg/g,加标回收率在94.17%～99.15%之间,相对标准偏差（relative standard deviation,RSD）在2.94%～4.87%之间;LC-MS/MS法的检出限为2.0～8.4 μg/g,加标回收率在89.05%～99.06%之间,RSD在2.21%～4.17%之间。本研究建立了2 种线性关系良好、低检测限、高灵敏度的检测方法,均可适用于市售麦粉产品中烷基间苯二酚同系物定性定量分析,将为麦类全谷物产品品质控制与检测提供技术指导。     

Analysis for perfluorocarboxylic acids/anions in surface waters and precipitation using GC--MS and analysis of PFOA from large-volume samples

The presence of perfluorocarboxylates (PFCAs) in the environment is of increasing concern, following the discovery of perfluoroalkyl acids (PFAs) in wildlife and human samples. Here we report a method forthe determination of (C2-C9) PFCAs by preparing the 2,4-difluoroanilides of the acids and analyzing by using GC-MS. Detector response was linear over the range 0.1 -1000 pg of each perfluoroalkyl anilide. A complete suite of PFCAs can be analyzed in an individual sample with the PFCAs detected at levels similar to or lower than those determined by other methods. For a comparison between the present method and the more common LC-MS/MS method, 10 replicates of a sewage treatment plant discharge were analyzed for perfluoro-octanoic acid (PFOA) using both methods. Results were nearly identical with low standard deviation (GC-MS 30.9 +/- 1.88 ng/L; while the LC-MS/MS 34.7 +/- 3.05 ng/L). PFCA concentrations for water samples collected from depth profiles in mid-Lake Ontario were analyzed by GC-MS with most PFCAs (C2-C8) present above the detection limit (0.5 ng/L). Major PFCAs were trifluoroacetate (TFA) (100 ng/L) and perfluorobutanoate (PFBA) (> 5 ng/L). Results for PFOA (2.5 ng/L) were in good agreement with recent analyses by LC-MS/MS. PFCAs were also detected in the precipitation samples at concentrations lower than those of the samples from the lake profiles or sewage treatment plants (STPs) effluent. Since PFOA levels may be less than the lower detection limit (<0.5 ng/L) in 1 L samples, a method for large volumes using XAD-7 resin was developed that allows detection to 0.01 ng/L. This method was applied to Lake Superior samples which produced good agreement for C6-C9 PFCAs between regular analysis (GC-MS) and the XAD-7 followed by GC-MS analysis.     

Detection of DNA-bound advanced glycation end-products by immunoaffinity chromatography coupled to HPLC-diode array detection

Sugars and sugar degradation products are formed during food processing, but also endogenously in vivo. In vitro, nucleosides and DNA react readily with these carbonyl compounds during the formation of the two diastereomers of N(2)-carboxyethyl-2'-deoxyguanosine (CEdG(A,B)), leading to a loss of DNA integrity. Only little is known about DNA glycation in vivo and about the influence of nutrition on CEdG formation. In this study, we developed a sensitive method to analyze DNA glycation by HPLC. For this purpose, immunoaffinity chromatography (IAC) using a polyclonal antibody against N(2)-carboxyethylguanine (CEguanine) was coupled to HPLC-DAD. In some samples, peak identity was confirmed by LC-MS/MS. The recovery of CEguanine from the IAC columns was 52.5% +/- 3.6 (n = 4). Thus, it was possible for the first time to detect CEdG(A,B), N(2)-carboxyethylguanosine (CEG(A,B)), and CEguanine in 11 human urine samples. However, due to imprecision of IAC, valid quantification of the adducts could not be achieved. Furthermore, CEdG was also detected in the DNA of cultured human smooth muscle cells (SMCs) and bovine aorta endothelium cells (BAECs). In BAECs, CEdG(A,B) were found by HPLC-DAD and LC-MS/MS after immunoaffinity purification, whereas in SMCs DNA-advanced glycation end-products were only detected with the more sensitive LC-MS/MS method.     

Multi-residue analysis of captan,captafol, folpet,and iprodione in cereals using liquid chromatography with tandem mass spectrometry

ABSTRACT

In this study, we propose an improved analytical method for the multiresidue analysis of captan (plus its metabolite, tetrahydrophthalimide), folpet (plus its metabolite, phthalimide), captafol, and iprodione in cereals using liquid chromatography tandem mass spectrometry (LC-MS/MS). As captan, captafol, and folpet are easily degraded during homogenisation and extraction, samples were comminuted with liquid nitrogen, and both QuEChERS and ethyl acetate-based extraction workflows provided a satisfactory method performance. The optimised LC-MS/MS procedure with electrospray ionisation did not degrade these compounds, and offered sufficient method selectivity by resolving and minimising co-eluting matrix-derived interferences. The method also resolved the problem of non-specific mass spectra that these compounds usually produce on GC-MS analysis involving electron ionisation. The method performance was satisfactory for all 6 compounds at 0.01 mg kg^?1 and higher levels of fortification, and validated as per the SANTE/11813/2017 guidelines of analytical quality control in a wide range of cereals including rice, wheat, sorghum, and corn. The method provides special advantage of simultaneous analysis of captan, and folpet along with their metabolites (tetrahydrophthalimide, and phthalimide, respectively) in combination with captafol, and iprodione in a single chromatographic run. Although iprodione is known to degrade to 3,5-dichloroaniline, since this metabolite is not a part of the residue definition, it was not included in the scope of this method. As the method demonstrates satisfactory selectivity, sensitivity, accuracy, precision, and robustness in a wide range of cereal matrices, it is recommended for regulatory testing of these compounds in cereals.     

Quantitative determination of paralytic shellfish toxins in cultured toxic algae by LC-MS/MS

We developed a sample preparation and LC-MS/MS method for the determination of saxitoxins in toxic algae. Paralytic shellfish toxins (PSTs) were successfully separated by gradient elution on an amide column with the hydrophilic interaction mode and quantified with multiple reaction monitoring (MRM) detection in the positive ion mode. This method showed good performance in the summed LODs and LOQs for all 12 toxins, 25 and 84 nM, respectively. Next, extracts of cultured strains of a toxic dinoflagellate Alexandrium tamarense and a freshwater cyanobacteria Anabaena circinalis were treated in a short column of basic alumina and the toxic fractions were analysed by our LC-MS/MS method and by HPLC with fluorescence detection. Comparison of the results obtained by the two methods demonstrated that approximately equivalent results were obtained for both the dinoflagellate and the cyanobacteria. In addition, the retention time of the toxins showed acceptable shifts. Therefore, the clean-up of the toxic algal extracts by using the basic alumina column controlled unwanted chromatographic behaviour and variable ionisation efficiency during MS detection. LC-MS/MS for saxitoxins has great potential as a rapid analytical method for determining all primary saxitoxins in cultured algae.