液相色谱串联质谱法定量检测青花菜中L-硒甲基硒代半胱氨酸

建立了液相色谱串联质谱(LC-MS-MS)法测定青花菜中L-硒甲基硒代半胱氨酸(SeMC)含量的方法。植物样品经沸水提取,以甲醇-0.1%七氟丁酸水溶液(30∶70)为流动相,滤液经Waters Symmetry C18(50 mm×3.9 mm,5μm)分离,经在线电喷雾离子源(ESI)正离子化后,采用多反应离子监测方式(MRM)选择m/z184.0→(167.0,94.9)测定SeMC。SeMC的线性范围为0-200 mg/L,准确度在96%-114%之间,日内日间精密度(RSD)在±10%内。检出限为0.1 mg/kg。结果表明:本方法高效、准确,特异性强,样品处理简单,可准确定量富硒青花菜中的SeMC。     

pIL-12 delivered by polymer based nanovector for anti-tumor genetherapy

Finding more effective and safe non-viral vectors to transfer genes into cancer cells has become the key of immune gene therapy for cancer. Herein a triblock compound MPEG₂₀₀₀–PDLLA₄₀₀₀–MPEG₂₀₀₀ modified by cationic liposome DOTAP was used as a non-viral vector DOTAP/MPEG₂₀₀₀–PDLLA₄₀₀₀–MPEG₂₀₀₀ (DMPM) to effectively transfer interleukin (IL)-12 plasmid (pIL-12) into tumor tissue. IL-12 produced by transfected tumor cells successfully inducing lymphocyte proliferation and promoting interferon-γ (IFN-γ) secretion, which resulted in tumor cells death. The ability of DMPM to transfer pIL-12 and the immune effect induced by IL-12 in cells had been explored. The anti-tumor effect, mechanism and safety of pIL-12/DMPM in mice cancer model were investigated in this study. Our results showed that the pIL-12 transferred by DMPM was highly expressed both in CT26 cells and B16-F10 cells. IL-12 expressed in the culture supernatant of transfected tumor cells stimulated lymphocyte proliferation and promoted IFN-γ secretion. The experimental result confirmed that pIL-12/DMPM therapy significantly reduced tumor growth in mice model. We designed the nanocomposite DMPM to deliver pIL-12 for cancer treatment and explored its therapeutic efficacy and the underlying anti-tumor mechanism. Our study suggested pIL-12 loaded by DMPM complex would be an effective strategy for cancer treatment.     

离子色谱-串联质谱法检测茶叶中的高氯酸盐

建立了离子色谱-串联质谱检测茶叶中高氯酸盐的分析方法。选用高容量、强亲水性的IonPac AS20阴离子交换柱（2 mm）进行分离,以淋洗液自动发生器在线产生的70 mmol/L氢氧化钾为淋洗液等浓度淋洗,TSQ Quantiva三重四极杆质谱仪作检测器,采用电喷雾电离源负离子（ESI^-）模式、多反应监测（MRM）模式进行分析,内标法定量。结果表明,高氯酸盐在0.02~10.0 μg/L范围内线性关系良好,相关系数（r）为0.9991,定量限为2 μg/kg。运用该方法测定5种茶叶中的高氯酸盐,加标回收率为87.3%~112.2%。该方法具有操作简单、专属性强、灵敏度高等优点,可满足茶叶中高氯酸盐的检测要求。     

酒精度对高效液相色谱-荧光法分析白酒中氨基甲酸乙酯含量的影响

分析酒精度对高效液相色谱-荧光（HPLC-FLD）法测定白酒中氨基甲酸乙酯（EC）含量的影响,建立了快速检测白酒中EC含量的HPLC-FLD分析方法。通过比较不同酒精度下同一EC含量的峰面积,研究酒精度对EC含量测定的影响。结果表明,在5%~65%（v/v）酒精度范围内,酒精度与EC含量（峰面积）具有良好的线性关系,相关系数R²大于0.98,同时建立了不同酒精度间EC含量换算的相对校正系数。该方法在10~500 μg/L范围内呈良好的线性关系,R²大于0.9999,定量限为10 μg/L,加标回收率为98.9%~108.2%,相对标准偏差为0.6%~4.9%。评价了HPLC-FLD法的可靠性,将该方法与GC-MS方法比较,结果显示两种方法无明显差异。该方法简单、灵敏、准确,适用于白酒中EC含量的快速测定,具有较好的实际应用价值。     

The Criterion of Chaotic Pulsation in pulsating Stars

Up to now, the period-doubling bifurcation in variable star is identified through the existence of subharmonics in the poGer spectrum of light curves. Therefore the question is arisen: How to find a general criterion of period-doubling bifurcation in pulsating stars from theoretical analysis. It is discussed in this paper. We found that for the stellar pulsating mapping the bifurcation from a fixed point to a two-cycle occurs at parameter λ₁ = -0.63, i.e., adiabatic exponent Г₁ = 1.331.     

高效液相色谱法测定化妆品中的染料

采用反相高效液相色谱法测定化妆品中对苯二胺等５种染料中间体,以ＺｏｒｂａｘＣ８为固定相,Ｖ（三乙醇胺）∶Ｖ（水）∶Ｖ（乙腈）＝０．９５∶９４．０５∶５为流动相,加入磷酸调ｐＨ值为７．７,检测波长为２８０ｎｍ。样品用体积分数为９５％的乙醇超声提取,回收率为８７％～１０７％（ｎ＝６）,相对标准偏差为２．３％～６．４％。     

KED-ICP-MS法测定尿样中21种无机元素

人体血液和尿液等生物样品中元素含量，能够有效反映不同途径元素暴露的体内负荷信息。因此，建立生物样本中精准、快速和高通量的元素检测方法具有重要的卫生学意义。目前应用较多的尿液前处理方法主要有消解法和直接稀释法，这两种方法均有各自的不足。以精准获得人体尿样中多元素含量为目的，建立应用碰撞池技术（KED）的电感耦合等离子体质谱（ICP-MS）法准确定量人体尿样中低浓度的锰（Mn）、钴（Co）、钒（V）、铜（Cu）和锌（Zn）等21种无机元素含量的分析方法。在直接稀释法基础上，经水浴超声前处理后，使用ICP-MS对尿样中21种无机元素进行分析，研究了各待测元素在KED模式下背景等价浓度（BEC）的变化情况，通过使用氦气为碰撞气，应用动能歧视和氦气原子与干扰分子间的碰撞裂解降低多原子干扰等质谱干扰对测定的影响，同时应用标准加入法和在线内标校正基质效应和信号漂移对测定的影响。通过考察不同He流速对各元素BEC影响，优化了碰撞气流速和Rpq，选择He流速3.8 mL·min-1，Rpq=0.45为优化后的检测条件，在此条件下获得21种无机元素的检出限介于0.004~12.08 μg·L-1之间，各元素在0~200 μg·L-1范围内的线性相关系数（r）≥0.999，方法具有良好的线性关系。采用高低两水平加标回收实验来验证方法的准确度和精密度，各元素加标回收率在81.8%~112.6%之间，相对标准偏差（RSD）小于5%。将该方法与《尿中多种金属同时测定电感耦合等离子体质谱法》（GBZ/T 308-2018）标准相比较，待测无机元素的检出限和相对标准偏差等方法学指标均有较大改善。本方法简便、快速，能够满足实验室日常尿样中多种无机元素的准确检测要求，能够为突发公共卫生事件和临床人体尿样中多种微量元素的准确分析提供参考和依据。     

Identification of the tannins in traditional Chinese medicine Paeoniae Radix Alba by UHPLC-Q-Exactive Orbitrap MS

Paeoniae Radix Alba (PRA, dried root of Paeonia lactiflora Pall.) is a widely used as traditional Chinese medicine and tannins are one of their main bioactive ingredients. However, there are rarely systematically investigated in this study. This study aimed to establish a rapid, high selective, high sensitive and effective method based on UHPLC-Q-Exactive Orbitrap MS for simultaneous identification the tannins in PRA. Separation was performed on Thermo Scientific Hypersil GOLD™ aQ (100 mm × 2.1 mm, 1.9 μm) using gradient elution consist of 0.1% formic acid acetonitrile and 0.1% formic acid water as the mobile phase at a flow rate of 0.3 mL/min. The mass spectrometer was operated with Q-Exactive Orbitrap spectrometer in negative ion mode. Finally, a total of 106 constituents were identified in PRA by UHPLC-Q-Exactive Orbitrap MS, 75 of those were reported from PRA for the first time. This result laid the foundation for in-depth research on the material basis efficacy and provided scientific basis for the selection of quality marker of PRA.     

以化学学科关键能力为导向的化学实验探究试题的命制——以“硫化钠长期放置氧化产物检验的实验”为例

基于文献研究和真实实验探究,以“硫化钠长期放置氧化产物检验的实验”为素材命制高三实验探究试题,展示命制过程,阐释以化学学科关键能力为导向的化学实验探究试题的命制策略。