Optimization of a novel setup for an on-line study of elemental mercury adsorption by cold-vapor atomic absorption spectrometry

The objective of this work was developing a simple and stable time-based on-line setup for assessing the potential of mercury [Hg] vapor adsorption of the commercial sorbents used in air sampling and control operation followed by cold vapor atomic absorption spectrometry [CVAAS]. A special designed separation chamber was used where reduction of the injected Hg [II] solution took place. Purge gas passes through this chamber resulting to a prompt release of mercury vapor, purging into the adsorbent that regulated at the desired adsorption temperature. After sorbent saturation, in order to study the adsorption parameters of sorbents [activated carbon and bone char] such as breakthrough time [BTT], and adsorptive capacity, mercury gas stream was passed through the sorbents, directly transport to the CVAAS. Preliminary experiments concerning the reductant solution showed that SnCl[2] offers higher stability than NaBH[4]. Around the loading range 0.125-2.5 ml min-1 of 100 micro g l[-1] Hg[II] solution, a linear calibration curve with the equation peak area=0.134; loading flow=-0.017 and a correlation coefficient r=0.996 was obtained, and the detection limit was improved up to c[L]=1micro g l[-1]. The relative standard deviation of five measurements of lowest flow loading of Hg [II] was RSD=2.8%. The significant differences were observed in the breakthrough time and mercury adsorptive capacity between activated carbon and bone char [P=0.010]. This novel setup is suitable for an on-line study of elemental mercury adsorption, determination of breakthrough time and adsorption capacity, and because of its stable performance during all experiments; it can be applied to the time based studies

[ effect of hydrogen peroxide and solvent on photolysis of PCBs to reduce occupational exposure]

Polychlorinated biphenyls [PCBs] are toxic bio-accumulate components and may increase risk of adverse effects on human health and the environment. For different social, technical and economic reasons, significant quantities of PCBs contaminated transformer oil are still in use or storied. The study aimed to determine the effect of hydrogen peroxide and solvent on photolysis of PCBs to reduce occupational exposure. The photochemical annular geometry [500 ml volume] reactor was designed with a cylindrical low-pressure mercury lamp [UV-C Cathodeon TUV 6WE] with emission at 254 nm. The radiant power emitted by the lamp was 6w. The whole lamp was immersed in a reactor thermostat controlling of temperature at 32 +/- 2 oC. The PCBs was determined using GC/ECD and data was analyzed by SPSS. Degradation of total PCBs in terms of%10 and%20 of volume of H2O2 were 41%, 75% and 94%, respectively. The degradation of total PCBs in terms of ratio to solvent with oil transformer in 1:1, 2:1 and 3:1 was 61%, 75% and 94%, respectively. Our study show that UV-C photolysis of H2O2 leads to a degradation efficiency of PCBs only in the presence of isooctane, therefore indicating that the intermediates formation after ethanol oxidation are able to initiate PCBs degradation

Immunogencity of HAS-L7/L12 [Brucella abortus ribosomal protein] in an animal model

The immunogenic Brucella abortus ribosomal protein L7/L12 is a promising candidate antigen for the development of subunit vaccines against brucellosis. This study was aimed to evaluate the protection of recombinant Human Serum Albumin [HAS]-L7/L12 fusion protein in Balb/c mice. The amplified L7/L12 gene was cloned in pYHSA5 vector, pYHSA5-L7/L12 construct was transformed in Saccharomyces cerevisiae and the expressed protein from supernatant was purified by affinity chromatography. Balb/c mice were immunized in five groups by tHSA-L7/L12 fusion protein [group 1], Brucella abortus S19 [group 2], HSA [group 3], recombinant L7/L12 [group 4], PBS [group 5]. ELISA to detect antibody production, LTT test to assess antigen specific lymphocyte response were conducted prior to virulent B. abortus strain 544 challenge two weeks after the last injection. Bacterial counts from spleens of immunized mice were done four weeks after challenge. In ELISA tests, the specific antibodies exhibited a dominance of immunoglobulin IgG1 over IgG2a. In addition, the tHSA-L7/L12 fusion protein and L7/L12 elicited a strong T-cell proliferative response upon restimulation in vitro with recombinant tHSA-L7/L12 and L7/L12, suggesting the induction of a cellular immunity response in vivo. However, there was no significant difference in proliferative response of L7/L12 and tHSA-L7/L12 fusion protein [p > 0.05]. The L7/L12 and tHSA-L7/L12 fusion protein vaccines could also induce significant protection against challenge with the virulent strain B. abortus 544 in Balb/c mice [p.0.05]. The tHSA-L7/L12 fusion protein, similar to L7/L12 has the ability to induce antigen specific lymphocyte proliferation, stimulate humoral immunity and engender protection

Simultaneous analysis of trimethoprim and sulphamethoxazole drug combinations in dosage forms by high performance liquid chromatography

A sensitive high performance liquid chromathography [HPLC] analytical procedure was developed for the quantitive determination of trimethoprim [TM] and sulphamethoxazole [SM] in commercial dosage forms. C18 analytical column [stainless steel, 25 cm X 4.6 mm i.d.] was packed with 5-micro m particles of the reversed phase material and used for assays. Mobile phase containing 0.025 M sodium phosphate as aqueous phase and acetonitrile with 0.4% triethylamine as organic phase. The drugs were quantified at flow-rate of 1.2 ml/min, with ultraviolet detection at 260 nm. The minimum detectable quantities in assays were 100 ng/ml for SM and 75 ng/ml for TM. The method is well suited to routine application and adequate sensitivity with precision