轻质油品中元素硫的结构变化对其定量分析的影响

利用气相色谱-质谱联用仪开发了轻质石油馏分及石油产品中元素硫（S⁰）的定量分析方法,在此基础上,研究了不同温度下轻质石油馏分及石油产品中元素硫存在的结构形式。实验表明,该分析测定条件下油品中元素硫的结构会发生变化,生成少量S₂、S₆、S₇,且遵循一定规律,即S₂∶S₆∶S₇∶S₈的质量比为 0.13∶0.05∶0.04∶1.00,因此轻质油品中元素硫结构随温度变化对其定量分析无明显影响。     

液相色谱-串联质谱法测定饲料中黄曲霉毒素的研究

建立了液相色谱-串联质谱法测定饲料中6种黄曲霉毒素(包括黄曲霉毒素B1、B2、G1、G2、M1、M2)的方法。试样中的黄曲霉毒素经84%乙腈溶液超声提取后,用正己烷脱脂,过霉菌毒素多功能固相萃取柱净化,氮气吹至干,用流动相溶解后进行液相色谱-串联质谱法测定。方法的最低检出限为0.2μg.kg-1,定量限均为0.5μg.kg-1;标准工作液在0.5~100μg.L-1的范围内线性良好;加标浓度在1.0~100μg.kg-1范围内,饲料中黄曲霉毒素的回收率在66.1%~108%之间,批内相对标准偏差≤17.8%,能满足相关法规要求。     

LC/MS研究有机金属钌抗肿瘤化合物与蛋白酪氨酸磷酸酶模型化合物的相互作用

Protein tyrosine phosphatase 1B(PTP 1B) which contains a catalytic cysteine plays important role in the negative regulating of insulin signaling, and it has been investigated as a therapeutic target in type II diabetes and obesity. In the present work, the reactions of ruthenium anticancer complex[(ŋ⁶-cymene)Ru(en)Cl]PF₆ with the model compound(2-mercaptobenzanilide) were studied under physiologically relevant conditions. Then we treated the mono- and di-ruthenium product with GSH and H₂O₂ to mimic the inactivation and activation of PTP1B whilst [(ŋ⁶-cym)Ru(en)Cl]PF₆ binds to the active site of PTP1B. HPLC-ESI-MS time courses suggest that organometallic ruthenium complexes may inhibit the enzymatic activity of PTP1B by coordinating to the thiol in the active site, which may have important biological and pharmacologic significances in the treatment of diabetes and obesity.     

质谱学方法研究H＋(H2O)n(n＝4~16)团簇的解离过程

The forms of water vapor in the atomspheric circumstance were observed using a triple quadrupole mass spectromter. There was not any single H₂O, which were detected, and H^＋(H₂O)_n , n＝3-37 were the main forms of water in gas phase. The collisional induced dissociation (CID) mass spectrometry was studied, which showed that the main dissociation products of H^＋(H₂O)_n (n＝4-16) were H^＋(H₂O)₄ and/or H^＋(H₂O)₅.     

五氧化铀的电喷雾萃取电离串联质谱法制备与表征

Negatively charged organic uranyl species (HOUO₂OH), prepared with uranyl acetate using extractive electrospray ionization multiple-stage tandem mass spectrometry, reacted with oxygen to yield a novel UO₅ anion species in the gas phase. The molecular structure of UO₅ was confirmed by using collision-induced dissociation (CID) mass spectrometry experiments. The effects of experimental parameters on the yield of UO₅ anion were experimentally evaluated. The data have shown that the electron cloud radius (r) of the polyatom anion (e.g., HOUO₂OH) was tunable within the range r_inert≤r_Reactive≤r_{decomposition} by changing the collision energy of CID. This mechanism can be further used to catalyze a certain type of chemical reactions.     

气相色谱-质谱法测定高压汞灯真空度

高压汞灯石英管内惰性气体的填充是保证灯性能的关键因素。本研究采用气相色谱-质谱法测定高压汞灯真空度，测得氩气的相对质量校正因子和氩气/氮气的峰面积比(A_Ar/A_N2)，然后根据气体状态方程，计算出灯内氩气压力，并比较5种不同性能的高压汞灯灯管中氩气填充量的差异。结果表明，不同类型的高压汞灯其氩气压力明显不同，而同一类型的高压汞灯内氩气压力值国产的比国外的高，并从惰性气体（氩气）填充量的角度表征了高压汞灯的性能。     

H2O2浸泡对无机碳酸盐沉积11B的影响

Pretreatments were used to remove organic “contaminant” material prior to isotopic analyses of coral skeletal samples. We conducted one experiments to test the pretreatment effect of 30% hydrogen peroxide (H₂O₂) on the boron isotopic composition of inorganic carbonate. The experimental results indicate that H₂O₂ can change the boron isotopic composition.     

鸟嘌呤自由基阳离子的碰撞诱导解离实验和理论研究

An electrosprayed water/methanol of Guanosine and Cu(NO₃)₂ was observed to give rise to gas-phase guanine radical ion. The Collision-Induced Dissociation (CID) of guanine radical cation generates five competing dissociation channels to lose NH₃, HCN, CN₂H, H₂NCN and HNCO, respectively. At the same time, the DFT theory was also used to simulate the HCN lost channel. It was turned out that through the three complicated structure changes a [ 4. 1. 0] bicyclic ion intermediate was formed before kicking off the HCN.     

同位素稀释-超高效液相色谱-串联质谱技术分析婴儿配方奶粉中的维生素D

为了准确测定婴儿配方奶粉中维生素D的含量,建立了同位素稀释-超高效液相色谱-串联质谱联用技术分析维生素D含量的方法。样品经氢氧化钾皂化,用V（正戊烷）∶V（乙醚）=4∶1的混合溶液提取,采用Waters T₃色谱柱分离,以2 mmol/L甲酸铵-甲醇和2 mmol/L甲酸铵-水溶液为流动相进行梯度洗脱,采用电喷雾-正离子电离源多反应监测模式进行定性和定量分析,内标法定量。维生素D₂和维生素D₃在5～150 μg/L质量浓度范围内线性关系良好,维生素D₂和维生素D₃的检出限均为1.5 μg/kg,定量限均为5.0 μg/kg,方法回收率分别为97.0%～104.7%和92.7%～108.0%,日内和日间相对标准偏差均小于10%。该方法简单、灵敏度高、分析时间短、定量准确,适用于婴儿奶粉中维生素D的测定。     

大气颗粒物中三类有机组分的萃取分离净化和GC/MS测定

大气颗粒物中有机组分污染特征的研究,对我国城市空气质量监控与治理有重要意义。应用中流量PM2.5采样器采集2003年9月~2004年7月北京市大气颗粒物样品,建立了同时测定PM2.5中三类有机组分的实验方法。采用14%BF3/CH3OH溶液为有机酸衍生化试剂,并确定有机酸最佳衍生化反应温度和时间分别为40℃、45 min;采用自填SPE硅胶柱,实现了正构烷烃、多环芳烃和有机酸酯的完全分离,三类组分回收率都在70%~130%之间。采用GC/MS法定量检出76种化合物,包括C10~C34之间的25种正构烷烃,16种美国EPA优控PAHs,35种有机酸,这些有机酸包括diC2~diC11之间的10种二元酸、C10~C32之间的23种饱和脂肪酸以及C18:1、C18:22种不饱和酸。