Unexpected Formation of Metallofulleroids from Multicomponent Reactions, with Crystallographic and Computational Studies of the Cluster Motion.

New multicomponent reactions involving an isocyanide, terminal or internal alkynes, and endohedral metallofullerene (EMF) Lu3 N@C80 yield metallofulleroids which are characterized by mass-spectrometry, HPLC, and multiple 1D and 2D NMR techniques. Single crystal studies revealed one ketenimine metallofulleroid has ordered Lu3 N cluster which is unusual for EMF monoadducts. Computational analysis, based on crystallographic data, confirm that the endohedral cluster motion is controlled by the position of the exohedral organic appendants. Our findings provide a new functionalization reaction for EMFs, and a potential facile approach to freeze the endohedral cluster motion at relatively high temperatures.

Insight into the molecular arrangement of high-density polyethylene polymer chains in blends of polystyrene/highdensity polyethylene from differential scanning calorimetry and Raman techniques.

Polystyrene/high-density polyethylene (PS/HDPE) blends were synthesized by melt blending in a single screw extruder. Co-continuity measurements using solvent extraction and scanning electron (SEM) micrographs showed that co-continuity was obtained around 35% PS. Thermal analyses measurements revealed a reduction in crystallinity of the HDPE phase around the co-continuous composition. Raman analyses across the entire composition range of these blends showed an increase in the normalized integral intensities of the 1128 cm(-1) and 1061 cm(-1) stretching vibrations of the HDPE molecules. The presence of all-trans HDPE chains that are not packed into an orthorhombic structure is used to explain the simultaneous occurrence of reduced crystallinity and increased intensity of all-trans HDPE stretch vibrations.

A study of the interactions between carboplatin and blood plasma proteins using size exclusion chromatography coupled to inductively coupled plasma mass spectrometry.

To study the carboplatin-protein interaction, a sensitive method using size exclusion chromatography coupled to inductively coupled plasma mass spectrometry (SEC-ICP-MS) was developed. The complexes formed between plasma proteins and carboplatin were monitored and identified with this method. Composite blood plasma samples from patients who were undergoing chemotherapy were analyzed, and carboplatin was found to bind plasma proteins. In addition, blank plasma samples were spiked with carboplatin and were analyzed as a time course study, and the results confirmed that carboplatin formed complexes with plasma proteins, primarily albumin and gamma-globulin. To further substantiate the study, these two proteins were incubated with carboplatin. The binding between carboplatin and these proteins was then characterized qualitatively and quantitatively. In addition to a one-to-one binding of Pt to protein, protein aggregation was observed. The kinetics of the binding process of carboplatin to albumin and gamma-globulin was also studied. The initial reaction rate constant of carboplatin binding to albumin was determined to be 0.74 M(-1) min(-1), while that for gamma-globulin was 1.01 M(-1) min(-1), which are both lower than the rate constant of the cisplatin-albumin reaction previously reported.

Arsenic speciation analysis of human urine using ion exchange chromatography coupled to inductively coupled plasma mass spectrometry.

A sensitive and robust method for the determination of seven inorganic and organic arsenic species was developed using ion exchange chromatography combined with inductively coupled plasma mass spectrometry (IC-ICP-MS). Both anion and cation exchange columns were used in a complementary fashion. Arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)) and dimethylarsinic acid (DMA(V)) were selectively separated by an anion exchange column using sodium hydroxide (NaOH) gradient elution, while monomethylarsonous acid (MMA(III)), dimethylarsinous acid (DMA(III)) and arsenobetaine (AsB) were separated by a cation exchange column using 70 mM nitric acid as the mobile phase. Baseline separation, high repeatability and low detection limits (0.10-0.75 ng mL(-1)) were achieved. The spiked urine samples were analyzed with this method to evaluate the matrix effect on the method. The results suggest 1-10 dilutions should be made to urine samples before sample injection for the anion exchange analysis to minimize the matrix effect. To validate the method, a new standard reference material (NIST SRM-2670a) was also analyzed. The arsenic species in NIST SRM-2670a were determined by this method, and the sum of their concentrations agreed well with the total arsenic content certified for NIST SRM-2670a. Moreover, this method was applied to measure arsenic species in urine samples from one subject living in New Jersey who drank well water contaminated with arsenic. By this method, two key arsenic metabolites, MMA(III) and DMA(III), were found to be present in these urine samples, which has previously been rarely reported.