Fluorescence lifetimes in BO2 (A2Πu)

Fluorescence lifetimes and fluorescence quenching rates are reported for several vibronic levels in the A²Π_u electronic manifold of BO₂. The relationship of these results to earlier Hanle-effect measurements is discussed.     

A more sensitive MS detector does not obviously lead to a more sensitive assay: experiences with ES-285

In this paper the transfer of an existing method for the quantitative determination of the anticancer agent ES-285 in human plasma using liquid chromatography tandem mass spectrometry on an API 365 to an API 3000 mass spectrometer is described. The transfer appeared not to be straightforward. Problems arose resulting from carry-over and interferences. In addition, due to the expansion of the calibration range, data ought to be weighted with a different factor to increase the accuracy of the lower concentrations. After finding appropriate solutions for these problems, the lower limit of quantitation could be lowered from 10 to 1 ng/mL for ES-285 in human plasma. The usefulness and necessity of the modified assay was demonstrated by analysis of plasma samples from a patient receiving a low dosage of the drug.     

Estimation of metrological characteristics of the element analyzer EuroVector EA-3000 and its potential in the single-reactor CHNS mode

The bulk of the analytical data of a long period was used for estimation of RSD values of the CHNS analysis results obtained by EuroVector EA-3000 in the single-reactor mode. It is shown that the accident error level is conducted with the sample preparation procedure as well as with the properties of the certain analyzed samples. It is established that the experimental obtained CHNS analysis error levels significantly differ from those given in the technical specifications. In case of analysis of sample with the unknown composition the accidental errors of determination of each element are comparable with the standard sample ones.     

TS3000总硫分析仪分析低压力硫化氢的研究

通过时TS3000 总硫分析仪气体进样模块的简单改装,利用仪器的富集功能,使其可以分析由质量流量控制器原理发生的低含量、低压力的硫化氢气体,解决了TS3000 总硫分析仪不能检测压力较低样品的难题.对不同含量硫化氢样气体的分析结果表明,改装后的仪器仍具有很好的线性及准确度,同时验证了仪器改装方法的可行性.     

人血浆中胸腺肽α1的质谱定量方法初探

胸腺肽α1(Thymosinα1)是一种由28个氨基酸组成的新型免疫调节因子,它可以启动T淋巴细胞的成熟、刺激分泌干扰素及各种淋巴介素,以及增强自然杀伤细胞介导的细胞毒性。临床应用范围较为广泛,主要用于治疗恶性肿瘤所致的免疫功能低下,乙型、丙型肝炎及其并发症和严重感染或抗生素不能有效控制的感染等,具有广阔的应用前景。由于该药物人体用药后浓度低,仅为ng级,为了满足临床药代动力学的要求,本文将高分辨的QSTAR和API-3000LC-MS-MS相结合,对人血浆中胸腺肽α1含量的质谱定量方法进行了初步摸索。     

Superconducting behavior of amorphous Zr70Cu30

Measurement of the Meissner penetration depth, λ(T) were made in amorphous Zr₇₀Cu₃₀ samples. The results indicate that this amorphous alloy behaves as a BCS superconductor with 2Δ(0)?kT_c = 3.8, where Δ(0) is the superconducting energy gap at T=0 and T_c the critical temperature. It is also concluded that the low energy excitation, TLS, characteristics of amorphous material does not contribute to T_c.     

Biosensor immunoassays for the detection of bisphenol A

Bisphenol A (BPA) is a xenoestrogen found in the environment, in consequence, for the biosensor detection of BPA we raised antibodies (polyclonal (PAbs) and monoclonal (MAbs)) against a structural analogue of BPA, 4,4 bis-(4-hydroxyphenyl) valeric acid (BVA). The kinetics of the MAb-BPA interaction were evaluated and the MAb providing the highest affinity was directly immobilized onto the sensor chip surface to evaluate a direct assay. Afterwards, the performance of the MAbs and the PAbs was compared in an inhibition assay using a BVA-coated chip.The highest sensitivity (limit of detection (LOD) of 0.4 μg L⁻¹) was obtained with MAb 12 in the direct assay. However, the inhibition assay was the most robust and the PAbs showed the highest sensitivity (LOD of 0.5-1 μg L⁻¹). The antibodies were specific for BVA and BPA as only minor cross-reactivities were found toward structurally related compounds or other endocrine disruptors. In the inhibition assay (with a run time of 6 min), water samples spiked with BPA at different levels (0.5-50 μg L⁻¹) resulted in recoveries varying between 68% and 121%. The sensitivity of the inhibition assay could be improved 40 times (LOD of 0.03 μg L⁻¹ with the Mab 12-based assay) using solid phase extraction (SPE).