石墨消解-原子吸收测定土壤中的锌和镉

采用石墨消解的方法进行样品消解,并用原子吸收光谱法测定土壤中锌和镉的含量。实验结果表明:锌在石墨消解结合火焰原子吸收光谱法中锌浓度在1 mg/L以下成线性相关,相关系数R2=0.9995,该方法的最低检出限为0.02 mg/kg。而镉元素在小于10μg/L之间成指数函数相关,相关系数R2=0.99889,该方法的最低检出限为0.02 mg/kg。测定结果精密度、准确度令人满意。     

超声波消解-氢化物原子荧光光谱法测定聚合硫酸铁中砷

建立了氢化物原子荧光光谱法测定水处理剂聚合硫酸铁中微量砷的方法。在对比3种不同前处理方法基础上选择优化方法,即采用少量硝酸超声波直接消解样品,并优化了前处理消解条件。砷的方法检出限为0.002 mg/kg。在最佳条件下对18个聚合硫酸铁样品进行砷含量测定,砷含量均在0.15~0.45 mg/kg范围内,加标回收率为98.2%~109.4%。     

电感耦合等离子体光谱法测定鱼及鱼丸中硼元素的本底值

本实验采用硝酸高压密封消解的方法消解样品,电感耦合等离子体光谱法对泰州市售鱼及鱼丸中的硼含量进行测定,结果表明,该方法在0~1.0 mg/L的范围内呈良好的线性,相关系数为0.9999,检出限为0.016 mg/kg,具有较高的灵敏度,为鱼及鱼丸中硼元素本底值的判定提供参考依据。     

火焰原子吸收法测定纺织品中总铅总镉

研究了用微波消解方法消解纺织品样品,样液用火焰原子吸收分光光度计法测定样品中的总铅总镉。对影响其测定的各种因素进行分析,确定出最优化的测试条件。该方法检出限Pb为2.80 mg/kg,Cd为0.68 mg/kg,回收率为90%~110%,RSD小于5%。     

氢化物发生-原子荧光光度法测定涂料中硒

采用氢化物发生-原子荧光光谱仪(HG-AFS)对不同的涂料样品的硒含量进行定量分析。采用盐酸消解样品,以5%HCl介质作为载流,样品酸度控制在10%时进行样品分析。该方法检测范围内线性关系良好,其线性相关系数均达到0.999以上,检出限为0.02μg/kg。相对标准偏差均在5.0%以内,加标回收率在94.2%～108.2%之间,能够满足涂料中硒含量的日常检测需求。     

涂料中铅、铬、硒和钴含量的测定

建立了微波消解–电感耦合等离子体原子发射光谱检测技术(ICP–AES)和粉末压片–波长色散X射线荧光光谱检测技术(WDXRF)测定涂料中Pb、Cr、Se和Co含量的方法。测试结果表明,WDXRF和ICP–AES两种方法均可应用于涂料中Pb、Cr、Se和Co含量的测定。两种方法中,Pb、Cr、Se和Co检出限分别为3.6、1.2、0.5、1.5 mg/kg及0.08、0.004、0.057、0.002 mg/kg,回收率分别在91.5%~106.6%和90.7%~110.5%之间,相对标准偏差分别为1.2%~4.6%和1.6%~5.7%。与ICP–AES检测技术相比,WDXRF更简单、快速和环保,适合于涂料样品的批量检测。     

奶粉中铅含量检测的不确定度比较

分析比较了干法灰化、湿法消解和微波消解三种方法测定奶粉中铅含量检测的结果不确定度,并给出奶粉中铅含量不确定度报告。三种检测方法的不确定度按从大到小的顺序分别为:微波消解(0.15mg/kg)、湿法消解(0.06mg/kg)和干法灰化(0.05mg/kg)。由于微波消解的样品质量仅为其他两种方法的三分之一左右,致使其由样品质量和标准曲线拟合带入的相对标准不确定度是其他两种方法的三倍左右。该两种不确定度分量的区别对合成不确定度的贡献最大。     

微波消解-原子荧光法测定常见彝药中铅的含量

本文采用微波消解样品,氢化物发生-原子荧光光谱法测定几种常见彝药中铅的含量。通过研究分析,天油菜中铅含量1.830 mg/kg、包谷七铅含量2.565 mg/kg、刺梨粉铅含量0.804 mg/kg,都未超过我国药典中关于铅的限量标准的规定值。该方法操作简便、快速,相对标准偏差为0.8%～3.7%,结果令人满意。     

湿法消解-电感耦合等离子体发射光谱法测定聚酯中的锑

本文研究了聚酯的湿法消解条件,确定了样品消解温度和预处理操作条件,细化了电感耦合等离子体的实验条件和标准曲线的制作方法,建立了湿法消解-ICP-OES法测试聚酯中锑含量的方法。本方法适合于聚酯中锑含量为2~300 mg/kg的准确测定。     

氟化铵辅助消解结合ICP-MS测定滤棒中的7种元素含量

采用氟化铵辅助微波消解联合电感耦合等离子体质谱法测定卷烟滤棒中铬、镍、砷、硒、镉、汞和铅7种元素含量。以氟化铵/硝酸作为消解体系消解样品,考察了氟化铵用量、消解温度、消解时间对滤棒样品消解效果的影响。结果表明,最佳前处理条件为0.2 g滤棒样品在6 mL 60%硝酸和0.75 mL(12.66 mol/L)氟化铵溶液中消解,消解温度为175℃,恒温保持20 min。对不同样品进行测定,7种元素检出限在0.007～0.044 mg/kg之间,样品的加标回收率为92.50%～108.36%,相对标准偏差为1.71%～5.65%。该方法与传统方法同时测定滤棒样品7种元素含量相比较无显著性差异(P0.05)。方法使用试剂种类少,更加绿色环保,避免了直接使用大量氢氟酸带来的安全隐患,且能快速、准确的测定滤棒中7种元素的残留量。     

Effect of Different Deacidification Methods on Phytonutrients Retention in Deacidified Fractionated Palm Oil

Crude red palm oil of 11.4 % free fatty acid content was dry fractionated to obtain liquid crude red palm olein which was deacidified using enzyme (lipase from Rhizomucor miehei), solvent (ethanol), and chemical (aqueous sodium hydroxide), and its effect on physicochemical characteristics and phytonutrients retention was evaluated. Enzymatic deacidification showed 100 % product yield and no neutral lipid loss, whereas yields of 78 and 62 % and neutral lipid loss of 12 and 30 % were observed for solvent and chemical deacidification, respectively. Variation in viscosity (25.3–37.2 cSt at 40 °C), slip melting point (15–36 °C), monoacylglycerols (1.7–3.3 %), and diacylglycerols (5.8–27.9 %) were also observed. Carotenoid content was slightly reduced by enzymatic (535 mg/kg), solvent (556 mg/kg), and chemical (526 mg/kg) deacidification. Retention of phytonutrients such as phytosterols (1,235 mg/kg), total tocopherols (965 mg/kg), squalene (301 mg/kg), coenzyme Q₁₀ (25.9 mg/kg), and total phenolics (3 mg/kg) was highest following enzymatic deacidification. The IC₅₀ value of the enzymatic deacidified sample (21.8 mg/ml) indicates more radical scavenging activity than in samples obtained using solvent (42.0 mg/ml) and chemical (28.8 mg/ml) methods.     

沙枣树中总黄酮的分布规律研究

以醇提法提取沙枣树不同部位的黄酮类化合物,并利用NaNO2-Al(NO)3-NaOH显色体系紫外吸光光度法测定沙枣树各部位总黄酮含量,对黄酮类化合物在沙枣树中的分布规律进行分析研究。结果表明沙枣树中总黄酮分布分别为:树皮含37.0 mg/g,木质部含14.3 mg/g,果实含1.6 mg/g,叶子含18.8 mg/g,种子含18.6 mg/g。研究结果揭示,沙枣树不同部位总黄酮的含量有显著差异,其中沙枣树皮中含量最高,果实中含量最低。     

超声波萃取-高效液相色谱测定电子产品中多溴二苯醚

文章采用超声波萃取-高效液相色谱建立了测定电子电器产品中的方法：选用正丙醇作为萃取剂,采用超声波萃取装置对电子电器产品中的溴系阻燃剂,以甲醇/超纯水为流动相,在反相C18色谱柱上进行梯度淋洗,检测波长226 nm,该方法对于9种目标多溴二苯醚的回收率为92%~96%,相对标准偏（RSD）均小于5%,该方法的检测限为〈0.1 mg/kg,具有良好的准确性和精密度。可以满足RoHS指令中溴阻燃剂的测定分析。如用该方法对普通电路板进行测定,可知道其中PBDE-209的含量约为314.7436 mg/kg。     

多菌灵在柑桔及土壤中的HPLC残留分析方法

用稀盐酸和甲醇混合溶液提取柑桔和土壤样品中的多菌灵,并采用液相色谱法测定了样品中残留的多菌灵。检测线性范围为1~2000 ng,相关系数r = 0.9996,最低检出量1.0×10-10 g,最低检测浓度:土壤0.025 mg/kg;果肉、果皮和全果0.010 mg/kg。多菌灵在不同样品中的添加回收率在80.1%~105.4%之间,满足农药残留分析要求。     

Investigation of liquefied wood residues based on cellulose,hemicellulose, and lignin

Chinese eucalyptus was subjected to a liquefaction process using glycerol/ethylene glycol (EG) as liquefaction solvent. The effects of various liquefaction conditions, including reaction time, liquefaction temperature, acid concentration, and liquor ratio on the chemical composition of liquefied wood residues were studied. The results showed that the whole liquefaction process took place in two stages, the liquefaction yield of wood depended on the reaction temperature, acid concentration and liquor ratio. With increased acid concentration the liquefaction yield, acid‐insoluble lignin, and hemicellulose content of the residues were increased, and the relative content of cellulose was decreased. Fourier transform infrared (FT‐IR) analyses of the residues showed that hemicellulose and lignin were almost decomposed at the initial stages of reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Efficient Extraction of Fuel Oil Hydrocarbons from Wood

Abstract

Sequential cold (room temperature) extraction from aged contaminated wood samples (southern yellow pine) with acetone followed by n‐pentane (upon a 3–4 days of sample incubation with each solvent) yielded more than 90% analyte recovery for both ambient (natural moisture content) and water‐submerged wood, significantly exceeding the recoveries obtained with one‐step extraction using single solvents and/or their mixtures. By contrast, a much faster ultrasound/Soxhlet extraction led to a virtually complete analyte recovery while using a 1∶1 mixture of these two solvents. Evidence obtained indicates that a possible role for the first solvent, acetone (in addition to collection of loose analyte), is the removal of an aqueous barrier surrounding the strongly adsorbed hydrocarbon, thus enabling its extraction by the second (non‐polar) solvent. For larger analyte concentrations (>60 mg n‐hexadecane/g wood), the high‐affinity binding sites became saturated (yielding 5–10 mg unrecovered analyte/g wood), and then a single solvent was sufficient for a near‐quantitative extraction.     

溶剂型木器涂料中苯、甲苯、二甲苯含量的测定

研究了用毛细管柱气相色谱仪及内标方式测定溶剂型木器涂料中苯、甲苯、二甲苯含量的方法。该方法简捷、快速,准确度高,精确度高,适合于所有溶剂型木器涂料(特别是溶剂结构复杂的溶剂型木器涂料)中苯、甲苯、二甲苯含量的测定。     

Differentiation of Mechanically and Chemically Extracted Hazelnut Oils Based on their Sterol and Wax Profiles

The sterol and wax content of solvent extracted (SEHO) and cold pressed hazelnut oils (CPHO) were compared. A total of 48 samples from 19 hazelnut varieties were collected for two successive crop years from four different geographical districts in Turkey. Hazelnuts were processed to oil with a laboratory scale press, than the remaining oil in cake was extracted with n‐hexane. CPHO and SEHO were evaluated for their wax, sterol and squalene contents. Results showed that sterol, squalene and wax contents of all individual cultivars were higher in SEHO than those of CPHO, indicating the higher solubility of these compounds in solvent. Total sterol contents ranged between 1088.56 (Kargalak)—1609.39 mg/kg (Mincane) for CPHO and 1590.86 (Çak?ldak)—2897.26 mg/kg (Mincane) for SEHO. Hazelnut oils were found to be richer of C36‐38 esters than C40‐46 group. Total wax content was between 24.19 (Kargalak)—94.58 mg/kg (Ku?) for CPHO and 81.46 (Kargalak)—160.92 mg/kg (Akçakoca) for SEHO. The squalene amounts of the samples obtained by hexane extraction were between 499.75 (Allahverdi)—885.36 mg/kg (Cavcava), while it varied between 288.55 (Kargalak)—647.68 mg/kg (Mincane) in cold pressed oils. Significant and obvious variations between SEHO and CPHO were verified by principal component and hierarchical cluster analysis. Geographical discrimination was also achieved by discriminant analysis.     

落叶松鲜针叶精油的化学成分及杀虫活性研究

采用同时蒸馏萃取(SDE)法以正己烷为溶剂提取落叶松鲜针叶精油,并对其进行了气相色谱-质谱(GC-MS)分析,研究了落叶松鲜针叶精油与松木屑木醋液复配物对舞毒蛾2龄幼虫的杀虫活性。结果表明:落叶松鲜针叶精油得率为0.93%,共鉴定出63种成分,总GC含量为98.11%,GC含量最高的化合物为3-蒈烯(12.13%),其次是2,4-二(1-甲基-1-苯基乙基)苯酚(10.71%)。雌舞毒蛾引诱剂(+)-(7R,8S)-7,8-环氧-2-甲基十八烷的GC含量为0.10%。落叶松鲜针叶精油-木醋液(体积比1:9,稀释至原体积5倍)对舞毒蛾2龄幼虫喷雾法杀虫活性实验的校正死亡率24 h达到83.33%,优于木醋液5倍稀释液,且72h内无变化。落叶松鲜针叶精油与松木屑木醋液复配能起到增效作用。     

杭州下沙地区市售猪肝中铜、铁、锌含量分析

研究了杭州下沙地区市售猪肝中铜、铁、锌的含量。采用湿式消解法处理猪肝样品,使用火焰原子吸收法对猪肝中的铜、铁、锌的含量进行测定量分析。对从杭州下沙地区市售猪肝中选取的23个样品进行检验,测得结果为：铜含量范围为8．381～44．900mg／kg,RSD％为0．0738-1．2106;铁的含量范围为206．888～523．975mg／kg,RSD％为0．0413-0．4136;锌的含量为58．481～157．038mg／kg,RSD％为0．0915-7．4831。