Radicals in the living organisms

U ovom kratkom radu dan je pregled nekih novih istraživanja i spoznaja iz područja kemije radikala i funkcije radikala u organizmu. On treba poslužiti i kao kratki podsjetnik na važnost radikala u organizmu. Melanin je spomenut i kao primjer dugoživućega radikala i kao vrlo važan spoj (boja) u živih bića. Danje sažeti pregled novih istraživanja vezanih za reduktivnooksidativne procese kao i podsjetnik na načine stvaranja važnih radikala koji sudjeluju u tim procesima. Gdje je bilo moguće prikazane su nove znanstvene dvojbe i viđenja.In this short article, a review of new research in chemistry of radicals as well as their function in organisms has been presented. Emphasis has been put on the new results in the research of reduction and oxidation processes. This also includes reminder of the reactions by which important radicals participating in these processes are formed. Special attention has been given to the role of radicals in the organisms with melanin presented as both an example of a long - lived radical and very important compound (colour) in living beings. Where possible, the new dilemmas and points of view have been discussed

Radicals in the living organisms

U ovom kratkom radu dan je pregled nekih novih istraživanja i spoznaja iz područja kemije radikala i funkcije radikala u organizmu. On treba poslužiti i kao kratki podsjetnik na važnost radikala u organizmu. Melanin je spomenut i kao primjer dugoživućega radikala i kao vrlo važan spoj (boja) u živih bića. Danje sažeti pregled novih istraživanja vezanih za reduktivnooksidativne procese kao i podsjetnik na načine stvaranja važnih radikala koji sudjeluju u tim procesima. Gdje je bilo moguće prikazane su nove znanstvene dvojbe i viđenja.In this short article, a review of new research in chemistry of radicals as well as their function in organisms has been presented. Emphasis has been put on the new results in the research of reduction and oxidation processes. This also includes reminder of the reactions by which important radicals participating in these processes are formed. Special attention has been given to the role of radicals in the organisms with melanin presented as both an example of a long - lived radical and very important compound (colour) in living beings. Where possible, the new dilemmas and points of view have been discussed

Growth Season Photochemical Pollution over the UK Based on 1990-2006 Ozone Data

Ozone data from 13 rural and 11 urban sites for the growth season (April through September) during 1990-2006 have been analysed on the basis of recently introduced photochemical pollution indica-tors. The indicators predict that urban sites are prone to photochemical pollution, although compared to some rural sites, the urban sites have lower average ozone concentrations and showed lower values of time for which hourly average ozone concentration is above a threshold value. Interestingly, the frequency distribution of ozone concentrations, especially the frequency of very low (close to zero) concentrations, correlates well with the average ozone volume fraction during the growth period. The present analysis shows that photochemical pollution in the UK is less severe compared with photochemical pollution in central Europe and the Mediterranean region (Italy, Croatia, Slovenia).(doi: 10.5562/cca2177

On Photochemical Air Pollution Potential in Southern California Derived from Ozone Data from 16 Monitoring Stations

Average hourly ozone volume fractions from ten automatic monitoring stations in the Los Angeles and six in the Riverside area for the April through September season in the years 2000 to 2005 have been analysed on the basis of recently introduced photochemical pollution (PP) indicators. Although considerably high indicator values were found for almost all the stations, surprisingly, some (e.g. Palm Springs) exhibit low daily maximum-to-minimum ratios of hourly ozone values which is crucial for assessment of a low PP by the given indicator method, despite the overall high ozone concentrations recorded. At such stations, in contrast to elsewhere, a characteristic quasi normal distribution of all ozone hourly volume fractions exists which could be a consequence of poor vegetation or some special meteorological conditions there. Compared with a similar assessment in central Europe and the Mediterranean region, the present analysis shows that PP problems in California are significant. (doi: 10.5562/cca2008

Potentiometric Surfactant Sensor Based on 1,3-Dihexadecyl-1H-benzo[d]imidazol-3-ium for Anionic Surfactants in Detergents and Household Care Products

A 1, 3-dihexadecyl-1H-benzo[d]imidazol-3-ium- tetraphenylborate (DHBI-TPB) ion-pair implemented in DHBI-TPB surfactant sensor was used for the potentiometric quantification of anionic surfactants in detergents and commercial household care products. The DHBI-TPB ion-pair was characterized by FTIR spectroscopy and computational analysis which revealed a crucial contribution of the C–H∙∙∙π contacts for the optimal complex formation. The DHBI-TPB sensor potentiometric response showed excellent analytical properties and Nernstian slope for SDS (60.1 mV/decade) with LOD 3.2 × 10−7 M ; and DBS (58.4 mV/decade) with LOD 6.1 × 10−7 M was obtained. The sensor possesses exceptional resistance to different organic and inorganic interferences in broad pH (2–10) range. DMIC used as a titrant demonstrated superior analytical performances for potentiometric titrations of SDS, compared to other tested cationic surfactants (DMIC > CTAB > CPC > Hyamine 1622). The combination of DHBI-TPB sensor and DMIC was successfully employed to perform titrations of the highly soluble alkane sulfonate homologues. Nonionic surfactants (increased concentration and number of EO groups) had a negative impact on anionic surfactant titration curves and a signal change. The DHBI-TPB sensor was effectively employed for the determination of technical grade anionic surfactants presenting the recoveries from 99.5 to 101.3%. The sensor was applied on twelve powered samples as well as liquid-gel and handwashing home care detergents containing anionic surfactants. The obtained results showed good agreement compared to the outcomes measured by ISE surfactant sensor and a two-phase titration method. The developed DHBI-TPB surfactant sensor could be used for quality control in industry and has great potential in environmental monitoring

Analysis of Ozone Data by Photochemical Pollution Indicators in Colorado

In order to assess the situation with air pollution by ozone in Colorado region during sunny part of the year (April to September), recently introduced photochemical pollution (PP) indicators have been applied on acquired ozone data, i.e. hourly ozone volume averages. PP indicators show very low values at the majority of stations except for the two located in Denver and Arvada which are located in the centre of the highly populated area covered by this assessment. Some other stations (e.g. National Renewable Ener¬gy Labs) have somewhat high number of excess times during the growth period; total daily turnover of ozone is, however, rather low indicating absence of other photochemical pollutants (e.g. NOx) which, therefore, justify low values of PP indicators. Generally, our assessment method shows very low PP in the assessed area which is central, most populated part of the state of Colorado. (doi: 10.5562/cca2357

Investigation of non-methane hydrocarbons at a Central Adriatic marine site Mali Lošinj, Croatia

For the first time, volatile hydrocarbons were measured in Croatia, at Mali Lošinj in the period from autumn 2004 to autumn 2005. Mali Lošinj site is conveniently located as a gateway to Croatia for any potential pollution from either Po valley in Italy, or other locations in southern Europe or even Africa. The sampling was performed on multisorbent tubes and then analyzed by thermal desorption gas chromatography with a flame ionization detector. The aim was to determine and estimate the non-methane hydrocarbons in Mali Lošinj, a location with Mediterranean vegetation and species which emit large quantities of volatile organic compounds. Ozone volume fraction and meteorological parameters were also continuously measured, from April to October 2005. Ethane, ethene, ethyne, propane, propene, n-pentane, n-hexane, benzene and toluene were identified in all air samples. Benzene and toluene have been found in ambient air and significant positive correlations between ethyne and ethane, propane and propene indicate emissions from transport

The 1,3-Dioctadecyl-1<i>H</i>-imidazol-3-ium Based Potentiometric Surfactant Sensor for Detecting Cationic Surfactants in Commercial Products

A low-cost and fast potentiometric surfactant sensor for cationic surfactants, based on the new ion-pair 1,3-dioctadecyl-1H-imidazol-3-ium-tetraphenylborate (DODI-TPB), is presented. The new cationic surfactant DODI-Br was synthesized and characterized by NMR, LC-MS, and elemental analysis, and was used for synthesis of the DODI-TPB ionophore. The DODI-TPB surfactant sensor was obtained by implementation of the ionophore in PVC. The sensor showed excellent response characteristics with near-Nernstian slopes to the cationic surfactants DMIC, CPC, CTAB, and Hyamine 1622. The highest voltage responses were obtained for DMIC and CPC (58.7 mV/decade of activity). DMIC had the lowest detection limit (0.9 × 10−6 M) and the broadest useful linear concentration range (1.8 × 10−6 to 1.0 × 10−4 M). An interference study showed remarkable stability. Potentiometric titration curves for the titration of cationic surfactants (DMIC, CPC, CTAB, and Hyamine 1622), with DDS and TPB used as titrants, showed sigmoidal curves with well-defined inflexion points and a broad signal change. The standard addition method was successfully applied with recovery rates from 98.9 to 101.2 at two concentrations. The amount of cationic surfactant found in disinfectants and antiseptics was in good agreement with the referent two-phase titration method and the surfactant sensor on the market. This new surfactant sensor represents a low-cost alternative to existing methods for cationic surfactant detection