苹果果实各部位菊酯类农药残留量分析

用正己烷-丙酮(体积比为1∶1)作提取剂,采用石英毛细管柱、电子捕获检测器,用气相色谱法测定苹果果皮、果肉、果核中甲氰菊酯、氯氰菊酯、氰戊菊酯、溴氰菊酯农药残留量.对苹果果肉试验结果表明,甲氰菊酯的回收率为80.9%～103.6%,相对标准偏差为1.30%～5.18%;氯氰菊酯的回收率为86.1%～103.9%,相对标...     

添加丙酮与乙酸乙酯对生物油稳定性的影响

为了探究丙酮与乙酸乙酯对生物油储存特性的影响,将不同质量分数（3%、6%、9%、12%、15%）的丙酮和乙酸乙酯分别加入到生物油中,考察各组生物油理化特性随储存时间的变化。结果表明,添加丙酮和乙酸乙酯降低了生物油的含水率,且乙酸乙酯对生物油水分的降低效果优于丙酮。储存35 d后,15%乙酸乙酯组生物油的含水率为13.41%,比空白组（16.32%）降低了17.8%。加入添加剂后各组生物油的运动黏度均显著下降,与乙酸乙酯相比,丙酮对运动黏度影响较大。随着添加剂添加比例的增加,生物油运动黏度降低。储存35 d后,添加丙酮质量分数为3%、6%、9%、12%、15%的实验组生物油的运动黏度比空白组分别降低了37.20%、57.78%、71.92%、79.79%、84.67%。两种添加剂均能使生物油的pH值略微增大。红外光谱分析和气相色谱质谱联用分析显示,丙酮和乙酸乙酯抑制了生物油的老化反应。     

Losses of chlorophylls and carotenoids in aqueous acetone and methanol extracts prepared for RPHPLC analysis of pigments

Summary RPHPLC methods for analysis of photosynthetic pigments (chlorophylls and carotenoids) usually require addition of water to methanol or acetone extracts to prevent distortion of early-eluting peaks corresponding to the more polar compounds. In this work we have investigated the short-(<2 min) and long-term (up to 48 h) effect of adding water to acetone and methanol extracts from two marine phytoplankton species,Emiliania hyxleyi andDunaliella tertiolecta. Solvent extracts were prepared and separated into fractions that were subsequently diluted with water to 90%, 80%, 70%, 60%, 50%, and 40% for methanol, and the same range extended to 30% and 20% for acetone. Changes in pigment concentration with time were followed spectrophotometrically and chromatographically. Losses of pigments as a result of precipitation were clearly observed immediately after dilution of acetone extracts to 60% or less and methanol extracts to 80% or less. For chlorophyll a the most substantial losses were recorded for 50% acetone (up to 27% decrease) and for 70% methanol (31% decrease). This effect increased considerably with time. Only for 90% and 80% acetone were the initial concentrations of all the pigments unchanged after 24h, and even up to 48 h. In contrast, more than 60% and 57% of the initial amounts of chlorophyll a were lost after 24 h in 50% acetone and 70% methanol extracts, respectively. These losses increased to 83% and 60% after 48 h. There was a clear correlation between the polarity of a pigment and the polarity of the solvent at which maximum precipitation occurred. Losses of pigment from pure acetone and methanol extracts with time were also observed, although we attribute these to pigment degradation rather than precipitation. Some of the losses occurring with time can be avoided by use of autosamplers in which the sample can be mixed with water immediately before injection.     

陶瓷辊棒在辊道窑使用过程中晶相结构与性能变化

采用XRD和SEM方法表征不同位置辊棒的晶相结构与显微结构来探讨陶瓷辊棒在实际窑炉使用过程晶相结构和性能变化。采用物理方法表征辊棒的性能。实验结果表明:不同位置辊棒存在莫来石、刚玉、硅酸钙镁三种晶相。莫来石含量是按未使用的(80.8%)→预热带的(78.4%)→烧结带的(73.4%)→冷却带的(71.5%)的顺序降低;刚玉含量按17.7%→19.2%→18%→22.5%的顺序变化;而晶相硅酸钙镁含量按1.5%→2.4%→7.6%→6%的顺序变化;体积密度和使用寿命按上述顺序降低的,而气孔率和吸水率按上述顺序增加的。     

Simultaneous quantitative determination of liraglutide and insulin degludec in rat plasma by liquid chromatography–tandem mass spectrometry method and its application

A simple, fast and high-throughput LC–tandem mass spectrometry method was developed and validated to simultaneously measure liraglutide and insulin degludec in rat plasma. After protein precipitation, plasma samples were subjected to gradient elution using an InertSustain Bio C₁₈ column with 1000/20/1 water/acetonitrile/formic acid (v/v/v) and 1000/1 acetonitrile/formic acid (v/v) as the mobile phase. The method was validated from 1.00 to 500 ng/mL of liraglutide and insulin degludec. Further, the extraction recovery from the plasma was 41.8%–49.2% for liraglutide and 56.5%–69.7% for insulin degludec. Intra- and inter-day precision of liraglutide was 3.5%–9.4% and 8.4%–9.8%, respectively, whereas its accuracy was between −12.6% and −1.3%. Intra- and inter-day precision of insulin degludec was 5.2%–13.6% and 11.8%–19.1%, respectively, showing an accuracy between −3.0% and 9.9%. As a result, the method was successfully applied to a pharmacokinetics study of liraglutide and insulin degludec following a single-dose subcutaneous administration to rats.     

高效液相色谱法检测液态奶中的苯酚类和水杨酸苯胺类抗蠕虫药

采用高效液相色谱法建立了硝碘酚腈、氯羟柳胺、氯氰碘柳胺、碘醚柳胺在液态奶中的多残留检测方法。取5 g样品,用含1%(v/v)三乙胺的乙腈提取,经MAX柱净化。以乙腈和0.02 mol/L乙酸铵水溶液(pH 4.0)作为流动相,经C18反相色谱柱分离后用紫外检测器检测,外标法定量。结果表明:空白加标奶样中4种药物在5~500 μg/kg范围内均呈现良好的线性关系,相关系数均大于0.99。空白加标奶样品的检出限(LOD)为3 μg/kg,定量限(LOQ)为5 μg/kg。硝碘酚腈、氯羟柳胺、氯氰碘柳胺、碘醚柳胺在1/2最高残留限量(MRL)、1倍MRL、2倍MRL添加水平下的平均回收率和相对标准偏差分别是92.20%~96.13%和5.55%~16.30%; 87.40%~94.74%和5.40%~12.21%; 86.97%~91.09%和2.67%~8.17%; 77.86%~95.36%和5.02%~13.15%。表明该检测方法简单,灵敏,适用于液态奶中水杨酸苯胺类多残留的定量分析检测。     

Stress-induced increase in the amounts of maysin and maysin derivatives in world premium natural compounds from centipedegrass

The red leaves of centipedegrass are known to produce compounds with stronger antibiotic effects than those produced by green leaves. Therefore, the aim of this study was to identify if stress methods (e.g., gamma irradiation, UV-B irradiation, and wounding) could effectively convert green leaves to red leaves, and thereby increase the production of maysin and maysin derivatives that have been known for antibiotic properties. Our results showed differential concentration changes for different compounds using these stress methods. The concentrations of luteolin increased from 0.014% to 0.019%, 0.022%, and 0.028% following gamma irradiation, UV-B irradiation, and wounding, respectively. The concentration of isoorientin increased from 0.898% to 1.938% and 2.538%, while the concentration of mixed rhamnosylisoorientin and orientin increased from 0.303% to 0.474% and 0.690%, following UV-B irradiation and wounding, respectively. Gamma irradiation produced concentrations of isoorientin, rhamnosylisoorientin, and orientin similar to those found in red leaves. The concentrations of derhamnosylmaysin increased from 0.004% to 0.009%, 0.015%, and 0.024% by gamma irradiation, UV-B irradiation, and wounding, respectively. The concentration of maysin increased from 0.515% to 0.714%, 0.583%, and 0.777% by gamma irradiation, UV-B irradiation, and wounding, respectively, while the concentration of luteolin-6-C-boivinopyranoside increased from 0.324% to 0.834%, 0.979%, and 1.493% by gamma irradiation, UV-B irradiation, and wounding, respectively. According to these results, wounding and gamma irradiation are promising methods for increasing the concentrations of maysin and maysin derivatives.     

Local and non-local sources of airborne particulate pollution at Beijing--The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside Beijing

A new element tracer technique has firstly been established to estimate the contributions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles (TSP), 10%―70% of fine particles (PM2.5), and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% (38%―86%) of the total mineral aerosols in TSP, 69% (52%―90%) in PM10, and 76% (59%―93%) in PM2.5 in spring, and 69% (52%―83%), 79% (52%―93%), and 45% (7%―79%) in TSP, PM10, and PM2.5, respectively, in winter, while only ～20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Beijing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.     

Unmittelbare photometrische Bestimmung des Antimongehaltes von legierten St?hlen mit Jodid

Zusammenfassung Das photometrische Verfahren von Ploum [1,2] zur Antimonbestimmung mit Jodid in nichtlegierten Stählen wurde so modifiziert, daß einerseits die Arbeitszeit durch Vereinfachung der Methode herabgesetzt wird und es andererseits zur Untersuchung hochlegierter Stähle herangezogen werden kann. 20% Cr, 12% Ni, 3% Mo, 4% W, 2% Mn, 3% V, 1% Ti, 0,4% Si, 0,8% Nb, 0,04% Ta, 0,1% Co, 0,05% Al, 0,05% As, 0,014% Sn und 0,004% B haben keinen Einfluß. Cu > 0,2% stört. Es können Antimongehalte von 0,001–0,025% bestimmt werden.

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Direct photometric determination of antimony in alloy steels with iodide

The method of Ploum [1,2] for the direct determination of antimony in plain steels has been modified. It has been possible to reduce the working time in simplifying the method and to apply the procedure to the investigation of high-alloy steels. 20% Cr, 12% Ni, 3% Mo, 4% W, 2% Mn, 3% V, 1% Ti, 0.4% Si, 0.8% Nb, 0.04% Ta, 0.1% Co, 0.05% Al, 0.05% As, 0.014% Sn and 0.004% B have no effect. Cu >0.2% interferes. Sb contents from 0.001 to 0.025% can be determined.

     

基于双脉冲LIBS结合偏最小二乘回归的稀土元素定量分析

激光诱导击穿光谱(LIBS)是一种以激光为激发源的等离子体发射光谱分析技术,已有将其用于稀土元素的定量分析研究,但由于稀土矿基体差异大、元素含量低,定量分析灵敏度和准确度仍有待提高。通过使用单激光分束构造双脉冲LIBS系统,并结合偏最小二乘回归(PLSR)算法实现对稀土矿石样品中的稀土元素La、Dy、Yb和Y的定量分析。结果表明,双脉冲LIBS结合PLSR可建立更加稳定的定标模型,与常规基本定标法相比,La、Dy、Yb和Y元素的相对均方根预测误差(RMSEP)从0.0061 %、0.0037%、0.0045%、0.0280 %降低至0.0044%、0.0016%、0.0029%、0.0134%,平均相对预测误差(AREP)从10.88%、15.27%、6.42%、17.20%降低至6.67%、3.62%、4.10%、7.98%。因此,双脉冲LIBS结合PLSR方法可以有效地提高LIBS对稀土矿石中稀土元素的定量分析能力。     

苹果及土壤中的螺螨酯残留分析方法

研究并建立了用乙腈提取,弗罗里硅土净化,气相色谱-电子捕获检测器检测苹果和土壤中螺螨酯残留的分析方法.螺螨酯在苹果和土壤中的添加回收率分别为82.11%～100.36%和79.27%～94.55%,相对标准偏差分别为0.92%～6.84%和1.89%～8.57%.该方法的准确度、精确度以及灵敏度均达到农药残留分析的要求.     

Enzyme recovery and recycling following hydrolysis of ammonia fiber explosion-treated corn stover

Both cellulase and cellobiase can be effectively recovered from hydrolyzed biomass using an ultrafiltration recovery method. Recovery of cellulase ranged from 60 to 66.6% and for cellobiase from 76.4 to 88%. Economic analysis shows that cost savings gained by enzyme recycling are sensitive to enzyme pricing and loading. At the demonstrated recovery of 60% and current loading of 15 Filter paper units of cellulase/g of glucan, enzyme recycling is expected to generate a cost savings of approx 15%. If recovery efficiency can be improved to 70%, the savings will increase to >25%, and at 90% recovery the savings will be 50%.     

基于黑体辐射提高自由定标激光诱导击穿光谱(CF-LIBS)定量精度的方法

自由定标激光诱导击穿光谱(Calibration-Free LIBS,CF-LIBS)技术是定量分析行业发展的主要趋势之一。该技术可直接基于局部热力学平衡等离子体模型,通过LIBS光谱数据和谱线参数计算出等离子体参数和各元素含量。且无需使用标准样品建立定标曲线,该技术不受基体效应的影响,非常适合实时、在线和多元素同时分析。但由光学厚而引起的自吸收效应是影响定量分析的重要因素。通过对比实验光谱数据与黑体辐射强度,研究等离子体温度,提高光学系统收集效率,抑制自吸收效应对CF-LIBS定量结果的影响。经过黑体辐射校正后,基体元素Fe的测定含量从88.700%提升到94.575%,相对误差(RE)从8.072%降低到1.984%。微量元素Cr、Mo和V的测定含量分别从0.635%、0.096%和0.023%降低至0.698%、0.143%和0.022%,相对误差(RE)从13.723%、45.455%和21.053%降低至5.163%、18.75%和15.789%。整体的平均绝对误差(MAE)从1.994%降低至0.497%。玻尔兹曼图拟合回归曲线有了更高的线性度。拟合系数R²     

烟煤和无烟煤中碘的赋存形态及其环境效应分析

采用逐级化学提取和电感耦合等离子体质谱(ICP-MS)研究烟煤和无烟煤中碘的赋存形态。结果表明,烟煤和无烟煤中各种形态的碘含量由高到低依次都是有机态、铁锰氧化物结合态、水溶态、残留态、离子交换态和碳酸盐结合态。烟煤和无烟煤中有机结合态碘平均含量分别为47.4%±3.28%和43.3%±2.42%,Fe-Mn氧化物结合态碘分别为36.8%±3.70%和34.6%±4.77%,水溶态和离子交换态碘平均含量之和分别为10.3%±3.00%和14.3%±3.37%,碘的平均潜在淋失率分别10.9%和16.0%,平均潜在可淋失浓度分别为0.9μg/g和1.2μg/g。这说明无烟煤中生物有效态碘含量高于烟煤,在表生条件下烟煤和无烟煤中淋出的碘都能导致地表水中碘的浓度升高;无烟煤中碘的有利环境效应大于烟煤,而不良环境效应小于烟煤。     

溴酸钾滴定法测定铜冶炼烟尘中的砷含量

研究了测定铜冶炼烟尘中砷含量的溴酸钾滴定方法。对测定体系中的各共存元素进行研究,探讨了测定方法的各项测定条件,方法的相对标准偏差RSD为0.13%～0.61%,样品加标回收率在99.5%～100%,方法精密度高,准确度好,适用于铜冶炼烟尘中砷含量为1.00%～50.00%的测定。     

Volatile constituents of flowers and leaves of Anthemis hyalina

The chemical composition of the essential oils of the flowers and leaves of Anthemis hyalina were analyzed by GC and GC-MS for the first time. The oils were found to contain seventy-two components. cis-Chrysanthenyl acetate (14.9% and 17.8%), camphor (11.6% and 1.7%), terpinen-4-ol (8.3% and 1.2%), germacrene-D (5.1% and 2.1%), β-caryophyllene (4.1% and 5.4%), myrcene (3.6% and 16.9%), bicyclogermacrene (3.5% and 0.9%), α-pinene (2.3% and 4.1%), cis-β-ocimene (2.1% and 4.3%) and isospathulenol (0.4% and 4.3%) were found to be the major constituents of the oils of flowers and leaves respectively. Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 428–429, September–October, 2006.     

电感耦合等离子体发射光谱法(ICP-AES)测定高铼酸钾中的19种杂质元素

建立了一种用稀盐酸溶解样品,标准工作溶液中匹配钾,ICP-AES测定高铼酸钾中19种杂质元素的方法。在选定的仪器工作条件下,样品加标回收率(%)分别为：钠94.4～101、钙98.8～102、铝98.1～102、镁95.8～99.1、钴98.4～101、钼97.3～103、钛97.6～102、钒96.6～106、锆96.2～97.7、铬97.8～101、铜98.1～108、铁92.9～104、锰95.5～98.4、镍93.6～101、钯93.3～101、铅96.5～103、锌95.2～103、铂95.9～99.9、铑94.5～96.3;方法精密度RSD%(n=7)分别为：钠2.0～5.5、镁1.1～3.5、铝0.9～2.5、钙1.5～7.3、钴1.1～3.1、钼0.9～4.5、钛1.0～2.8、钒1.6～4.0、锆1.4～3.6、铬0.77～4.6、铜0.74～1.8、铁1.3～3.8、锰1.1～2.0、镍0.99～5.0、钯1.1～2.4、铅1.3～9.1、锌0.80～6.7、铂1.2～10、铑0.78～8.6。方法简便、快速、准确, 满足生产分析要求。     

缓释尿素中硝化抑制剂DMPP的气相色谱法测定

建立了一种检测缓释尿素中吡唑类硝化抑制剂DMPP的气相色谱法。DMPP在尿素水溶液中可定量转化为DMP,从5种有机溶剂中选择氯仿作为DMP的萃取剂,并采用加入KCl盐析的方法将萃取率从96.1%提高到99.5%。本文采用吡啶作为内标物,通过DB-1701气相色谱柱,氢火焰离子化检测器(FID)定量检测氯仿溶液萃取相中的DMP。萃取率为98.8%~100.4%;添加回收率为98.1%~99.5%;RSD为0.84%~1.6%。应用本法测定自制缓释尿素中DMPP质量分数为0.44%。     

成都市东郊土壤中重金属元素垂直分布研究

采用王水消解样品,利用原子吸收分光光度法,对重金属元素(Cu、Pb、Zn、Cd)在成都市东郊土壤中的垂直分布进行了研究。该法对Cu的回收率为98%~104%,精密度为2.75%;Pb的回收率为95~97%,精密度为3.11%;Zn的回收率为99%~101%,精密度为2.31%;Cd的回收率为97%~102%,精密度为3.32%,测定方法简单、准确。     

有机脱模剂中多环芳烃的高效液相色谱测定

建立了有机硅类和金属皂类脱模剂中多环芳烃的高效液相色谱测定方法。方法所用色谱柱为多聚C18(LC-PAH)柱,流动相为乙腈/水,采用梯度淋洗方式,开始时为体积分数40%乙腈,28min后变为82%乙腈,48min后变成100%乙腈,保持8min。方法的线性范围为0.10~200mg/L,线性相关系数为0.9993~1.0000,平均回收率分别为68.55%~101.2%(有机硅类)和75.29%~99.89%(金属皂类),精密度RSD分别为1.6%~8.1%(有机硅类)和1.8%~6.8%(金属皂类),检出限(S/N=3)分别为0.05~0.10mg/L(有机硅类)和0.05~0.20mg/L(金属皂类)。该方法可以满足有机硅类和金属皂类脱模剂中多环芳烃的检测要求。