The 1,4-addition of singlet oxygen to 2,6-dimethoxy-1-(2-methoxyethenyl) benzene and 2-methoxy-1-(2-methoxyethenyl)naphthalene. The 1,4-endoperoxides as equivalents of 6-oxo-2,4-cyclohexadienylidenacetates.

The sensitized photooxygenation of vinylarenes $\text{1}$ and $\text{2}$ gave the corresponding 1,4-endoperoxides which were decomposed under mild conditions into quinone methides bearing ester function at the exocyclic carbon.     

Determination of histamine, 1-methylhistamine and N-methylhistamine by capillary electrophoresis with micelles

Urinary histamine and Ngamma-methylhistamine (1-MH), a histamine metabolite, are highly correlated with histamine in plasma. Therefore, allergic reactions can be examined by determination of histamine and 1-MH in urine. We separated histamine, 1-MH and Nalpha-methylhistamine (N-MH) by capillary electrophoresis with UV detection at 210nm, using borate buffer (pH 9) containing 100 mM SDS. The absolute detection limits were 200, 100 and 50 pg for histamine, 1-MH and N-MH, respectively. To purify histamine 1-MH and N-MH in urine, a silica cartridge was used. Recovery rates of histamine, 1-MH and N-MH in physiological saline were 90.0, 91.4 and 95.4%, respectively. We measured histamine and 1-MH levels in urine from a normal female volunteer before and after a meal, and a male bronchial asthma patient. The results showed clearly that the concentrations of histamine and its metabolite rose after eating or asthma attack. N-MH was not detected in the urine.     

Rapid determination of total mercury in treated waste water by cold vapor atomic absorption spectrometry in alkaline medium with sodium hypochlorite solution

Addition of a sodium hypochlorite solution (9.2% (w/v)) was effective to reduce a sulfide interference in determination of organic mercury, including methylmercury and phenylmercury, as well as a previously reported determination of inorganic mercury by cold vapor atomic absorption spectrometry (CVAAS) in an alkaline medium. Total mercury ranging from 0.17 to 33 μg L⁻¹ in 15 mL of sample solutions containing up to 200 mg L⁻¹ of sulfide can be determined without any serious interference by sulfide when 1 mL of the sodium hypochlorite solution was added after dilution of the sample solution to 25 mL. The proposed method was simple and rapid because no digestion processes were required for the determination of total mercury; the time required for the determination was only about 5 min. The proposed method was applicable to the analysis of treated waste water.     

Preparation of a fluorescent derivative of benzoylecgonine, and preliminary studies of its application to the analysis of urine.

A sensitive high-performance liquid chromatographic method using 3-bromomethyl-6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone (Br-DMEQ) as a fluorescent labeling reagent is described for the determination of benzoylecgonine (BE) and ecgonine (EC). The Br-DMEQ derivatives of BE and EC were separated on a C18 column and detected at 455 nm with excitation at 370 nm. The detection limits of the proposed method were 18.7 fmol for BE and 12.5 pmol for EC at a signal-to-noise ratio of 3. Relative standard deviations of five replicate measurements were 1.94% (10 pmol) and 2.98% (50 pmol) for BE and 6.3% (250 pmol) and 5.62% (1.25 pmol) for EC. This method was applied to the determination of BE in human urine. BE was extracted from urine by solvent extraction with chloroform-isopropyl alcohol (9:1, v/v) solution. Levels of 2.5.10(-8) M BE in urine (25 pmol/ml) could be determined.     

Neutron activation analysis of scandium

A neutron activation method is proposed for the determination of trace quantities of scandium, down to submicrogram level, in rocks, ores and meteorites. The sample and standard are irradiated intermittently for a total of 30 h, at a neutron flux of 5·10¹¹ n/cm²/sec; the radiochemical separation consists essentially of a one-step anion exchange. The induced γ-activity of ⁴⁰Sc, 85 days, isolated from the sample is measured and compared with that of a standard. The chemical yield averages 85% and there is a considerable saving of time in the radiochemical work. Results are quoted for the scandium contents of 2 standard rocks, cassiterite and several stony meteorites. Details of conflicting nuclear reactions are also given.     

Partial purification, and some properties and reactivities of cetraxate benzyl ester hydrochloride-hydrolyzing enzyme

Debenzylating enzyme from Aspergillus niger enzyme (commercial crude cellulase) catalyzes the hydrolysis of cetraxate benzyl ester hydrochloride (2), a precursor of the antiulcer agent (1). The enzyme was highly purified by three kinds of chromatographies (hydrophobic, ion exchange, gel filtration) with a recovery of 36%. The content of the debenzylating enzyme was about 0.1% in the crude cellulase, but the enzyme showed no cellulase activity. The purified enzyme was inactivated by Hg2+, and diisopropyl phosphorofluoridate (DFP). It was a monomer with a molecular weight of about 35,000, and its isoelectric point was estimated to be 5.3. It showed a debenzylating activity for the phenylpropionic acid benzyl ester moiety of various benzyl ester derivatives, and the benzyl ester of phenylalanine or that of tyrosine was also well hydrolyzed.     

Determination of trace quantities of tin by neutron activation analysis

A neutron activation method of general applicability has been developed for determining traces of tin in a variety of samples. The samples and comparative standards, sealed into ampoules, are irradiated intermittently for 3 days at a neutron flux of ca, 3 · 10¹¹ n/cm²/sec, followed by carrier radiochemical separations mainly consisting of solvent extraction steps. As little as 0.1 μg Sn can be easily determined by comparing the induced β-activity of ¹²¹Sn (27.5 h) with that of a standard, The method is rapid and has a reasonably high chemical yield of about 50%. Results are quoted for the tin contents of a number of materials including silicate rocks, sea waters, biological materials and steels.     

Formation of hydroxynorspermidine from exogenously added 1,3-diaminopropan-2-ol in Vibrio species

When Vibrio parahaemolyticus AQ 3627 was grown in the presence of 1,3-diaminopropan-2-ol (OH-Dap), a new compound accumulated in the cells. This was identified as hydroxynorspermidine (OH-Nspd), N-(3-aminopropyl)-1,3-diaminopropan-2-ol, by gas chromatography-mass spectrometry and thin-layer chromatography. It was also synthesized enzymatically from OH-Dap by a cell-free preparation from this strain. All other Vibrio strains examined also showed the ability to synthesize this compound, but none of the non-vibrio organisms did, indicating that OH-Dap is an in vivo substrate for the enzyme responsible for biosynthesis of norspermidine characteristically present in vibrios. These results suggest that the ability to synthesize OH-Nspd from OH-Dap present in the growth medium may be useful as an additional identifying factor for the genus Vibrio.     

The structures of satellite bands in the X-ray photoelectron spectra of potassium bromide

The structures of the satellites accompanying the Br 3p, Br 3d, K 2s and K 2p peaks of the X-ray photoelectron spectra of KBr were investigated. It is shown that these satellites are not simply due to discrete photoelectron energy-loss, but possibly due to a shake-up process.     

Ion-exchange thin-layer chromatography of metal lons in organic solvent — Hydrochloric acid — Complexing agent media

Summary Thin-layers of strongly basic or strongly acidic ionexchange resins (Dowex 1 or Dowex 50), mixed with a plain cellulose, Avicel SF, have been used to investigate the chromatographic behaviour of 40 metal ions in acetic acid — hydrochloric acid — complexing agent media. The CIESE (combined ion-exchange-solvent extraction) effect, proposed by Korkisch, is noticed for scandium and thorium in the anion-exchange system involving trioctylphosphine oxide (TOPO) as the complexing agent, the system providing a basis on the specific separation of both elements. In the cation-exchange system involving TOPO, the metal ions are distributed chromatographically, so that the system allows multicomponent separations to be carried out. The system also reveals the CIESE effect for zirconium and hafnium.