DETERMINATION OF DEGREE OF CRYSTALLINITY OF NYLON 1212 BY WIDE-ANGLE X-RAY DIFFRACTION

Based on the X-ray scattering intensity theory and using the approximate expression for the atomic scattering factor, the correction factors for three crystalline peaks and an amorphous peak of Nylon 1212 were calculated and the formula of degree of crystallinity of Nylon 1212 was derived by a graphic multipeak resolution method. The degree of crystallinity calculated from the WAXD method is compatible with those obtained by density and calorimetry methods.     

用铍试剂测定人血清白蛋白的分光光度法

在pH3.6的缓冲溶液中，铍试剂Ⅲ与人血清白蛋白（HSA）能形成复合物，吸光度与HSA的含量呈线性关系；复合物的最大吸收峰波长λmax=460nm,比铍试剂本身紫移80nm左右；HSA标准曲线线性范围为20－140mg/L；实验表明该反应选择性、重复性很好，操作简便，适用测定含量范围宽，测定结果与传统的考马斯亮蓝法结果相吻合。     

Analysis of selected pesticides and alkylphenols in human cord blood by gas chromatograph-mass spectrometer

A total of seven pesticides and eight alkylphenols were monitored using this method for the determination of their trace levels in human cord blood. The pesticides are lindane, diazinon, α-endosulfan, β-endosulfan, endosulfan sulfate, chlorpyrifos and endrin; while the alkylphenols are 4-n-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol, 4-t-octylphenol, 4-n-heptylphenol, nonylphenol, 4-n-octylphenol and bisphenol A. The pesticides and alkylphenols in the cord blood samples were extracted with solid phase extraction IST C18 cartridges and analyzed by selected ion monitoring mode using quadrapole detector in Shimadzu QP-5000 gas chromatograph-mass spectrometer. Trace levels of pesticide and alkylphenols in the range of non-detectable to 15.17 ng ml⁻¹, were detected in the human cord blood samples. This technique of monitoring the levels of endocrine-disruptors in blood samples is consistent, reliable and cost effective while reducing wastage of time and solvents.     

应用单细胞微凝胶电泳技术研究氯化镉对人血淋巴细胞DNA的损伤效应

详细介绍了单细胞微凝胶电泳（ＳＣＧ）技术的原理和操作过程，并应用该技术研究了氯化镉（ＣｄＣｌ２）对人血淋巴细胞ＤＮＡ的损伤效应，结果表明，ＣｄＣｌ２能引起细胞ＤＮＡ迁移长度增加，且呈显著的剂量效应关系，对未处理对照细胞的ＤＮＡ迁移的原因及ＳＣＧ实验操作过程中应注意的事项也进行了讨论。     

On-line SFE-GC for determination of PCBs in human milk and blood serum

On-line coupled supercritical fluid extraction and gas chromatography (SFE-GC) has been utilized for the determination of PCBs and other organochlorine compounds in human milk and blood serum. The procedure involved preconcentration of the sample on C₁₈-silica sorbent in an extraction cell: after precipitation of the proteins up to 20 ml of human milk was concentrated on 0.5 g of sorbent. Serum (up to 5 ml) was applied to the C₁₈ material without pretreatment. Basic alumina was utilized as a selective adsorbent for lipids in the on-line SFE-GC system. The method was used to analyze milk and serum spiked with 0.5 and 10 ng of Aroclor 1260 and the results compared with those obtained by liquid–liquid extraction of serum.     

Using a new solvation model for thermodynamic study on the interaction of nickel with human growth hormone

Thermodynamics of the interaction between Ni²⁺ and human growth hormone (hGH) were determined at 27 °C in Nail solution by isothermal titration calorimetry. A new method to predict protein penetration and the effect of metal ions on the stability of proteins is introduced. The new solvation model was used to reproduce the enthalpies of Ni²⁺-hGH interaction over the whole range of Ni²⁺ concentrations. The solvation parameters recovered from the new equation, attributed to the structural change of hGH and its biological activity.     

CS2+离子 C2Σg+←B2Σu+跃迁的Franck-Condon因子计算以及与光解离谱的比较

将线性三原子分子离子CS2+的对称伸缩振动简化为SC和S之间的简谐振动, 用谐振子的势能曲线和波函数对CS2+分子离子 C2Σg+和 B2Σu+电子态(对称伸缩)振动能级间跃迁的Franck-Condon因子进行了计算, 得到的结果与 C2Σg+←B2Σu+跃迁的光解离谱实验强度进行了比较, 对前人给出的分子数据(转动常数、分子平衡核间距)进行了验证和分析, 讨论了经由 C2Σg+←B2Σu+电子态振动能级间跃迁的光解离机理.     

Simultaneous determination of 11 drugs belonging to four different groups in human urine samples by reversed-phase high-performance liquid chromatography method

A new, accurate, sensitive and fast reversed-phase high-performance liquid chromatography (RP-HPLC) as an analytical method for the quantitative determination of 11 drugs in human urine was worked out, optimized and validated. The objects of analysis were imipenem (IMP), paracetamol (PAR), dipyrone (DPR), vancomycin (VCM), amikacin (AMK), fluconazole (FZ), cefazolin (CFZ), prednisolone (PRE), dexamethasone (DEX), furosemide (FUR) and ketoprofen (KET) belonging to four different groups (antibiotics, analgesic, demulcent and diuretic). For HPLC analysis, diode array (DAD) and fluorescence (FL) detectors were used. The separation of analyzed compounds was conducted by means of a LiChroCART^® Purospher^® C₁₈e (125 mm × 3 mm, particle size 5 μm) analytical column with LiChroCART^® LiChrospher^® C₁₈ (4 mm × 4 mm, particle size 5 μm) pre-column with gradient elution. Analyzed drugs were determined within 20 min. The mobile phase was comprised of various proportions of methanol, acetonitrile and 0.05% trifluoroacetic acid in water. AMK was separated and determined from human urine using ortho-phthaldialdehyde-3-mercaptopropionic acid (OPA-3-MPA) as a fluorescent reagent by RP-HPLC-FL. The following retention times for drugs IMP, PAR, DPR, VCM, AMK, FZ, CFZ, PRE, DEX, FUR and KET in human urine were found: 4.01 min, 4.86 min, 6.71 min, 8.14 min, 9.46 min, 10.01 min, 10.90 min, 13.34 min, 14.06 min, 16.03 min and 18.98 min, respectively. Excellent linearity was obtained for compounds in the range of concentration: 0.35-42 μg ml⁻¹, 0.5-45 μg ml⁻¹, 4.5-38 μg ml⁻¹, 0.25-25 μg ml⁻¹, 0.5-35 μg ml⁻¹, 0.25-22 μg ml⁻¹, 0.03-52 μg ml⁻¹, 0.15-25 μg ml⁻¹, 0.25-28 μg ml⁻¹, 0.05-18 μg ml⁻¹ and 0.15-35 μg ml⁻¹ for IMP, PAR, DPR, VCM, AMK, FZ, CFZ, PRE, DEX, FUR and KET, respectively. The limits of detection (LOD) and limits of quantification (LOQ) for analyzed drugs were calculated in all cases and recovery studies were also performed. Ten human urine samples obtained from patients treated in hospital have been tested. In analyzed samples, one or more drugs from the 11 examined drugs were detected. The concentrations of examined drugs in urine samples ranged between: 1.5-12 μg ml⁻¹ of PAR, 5.2-11.5 μg ml⁻¹ of DPR, 0.13-9.5 μg ml⁻¹ of CFZ and 0.1-8 μg ml⁻¹ of FUR. This method can be successfully applied to routine determination of all these drugs in human urine samples.     

Effect of p-tert-Butylcalix[4]arene Fitted with Phosphinoyl Pendant Arms as Synergistic Agent in the Solvent Extraction and Separation of Some Trivalent Lanthanoids with 4-Benzoyl-3-methyl-1-phenyl-5-pyrazolone

The synergistic solvent extraction of five selected lanthanoid ions (La³⁺, Nd³⁺, Eu³⁺, Ho³⁺ and Lu³⁺) with a 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone(HP) and the 5,11,17,23-tert-butyl-25,26,27,28-tetrakis(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl₃ has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoids have been extracted as LnP₃ · S. On the basis of the experimental data, the values of the equilibrium constants have been calculated. The influence of the synergistic agent on the extraction process has been discussed. A synergistic effect of almost three orders of magnitude occurs in the extraction of Ln(III) with mixture of HP and S. The values of the separation factors (S.F.) between the adjacent elements have been evaluated. On the basis of the IR and NMR spectra the stoichiometry and the structure of the solid complexes of Eu(III) with HP and Eu(III) with HP and S were proposed.     

Determination of selenium in human milk by electrothermal atomic absorption spectrometry and chemical modification

A method was developed for the determination of selenium in human milk using electrothermal atomic absorption spectrometry. The use of chemical modifiers as well as their implications during the pyrolysis step was examined. The chemical modifiers that were studied were Zr, Ir as well as the mixed modifier Zr-Ir. The Ir modifier stabilized selenium at 1000 °C, Zr at 800 °C, while the mixed modifier at 1200 °C. The effect of modifier mass was studied and was found that better results are achieved with addition of 2 μg Zr and 2 μg Ir. The characteristic masses of selenium in the presence of Zr, Ir and the mixed modifier were found to be 73.3, 18.0 and 14.7 pg, respectively, while the corresponding limits of detection were found 2.0, 0.50 and 0.41 μg l⁻¹. Consequently better results were obtained with the mixed modifier. The developed method was applied for the determination of selenium in human milk, which was digested with a HNO₃ + H₂O₂ mixture in a microwave oven. The limit of detection of the method was 1.37 μg l⁻¹, the characteristic mass, m₀, was 48.8 pg and the repeatability was less than 5% as R.S.D.(%). Matrix matched calibration was used. Recoveries were estimated to be 93-105%. The method was applied to breast milk of Greek women (n = 9) and the Se content was found to be in the range 16.7-42.6 μg l⁻¹ with mean value 27.4 ± 5.5 μg l⁻¹.