Intermolecular Interaction in Methylene Halide (CH2F2, CH2Cl2, CH2Br2 and CH2I2) Dimers.

The intermolecular interaction in difluoromethane, dichloromethane, dibromomethane, and diiodomethane dimers has been investigated using high level quantum chemical methods. The potential energy curve of intermolecular interaction along the C⋯C bond distance obtained using the coupled-cluster theory with singles, doubles, and perturbative triples excitations CCSD(T) were compared with values given by the same method, but applying the local (LCCSD(T)) and the explicitly correlated (CCSD(T)-F12) approximations. The accuracy of other theoretical methods-Hartree-Fock (HF), second order Møller-Plesset perturbation (MP2), and dispersion corrected DFT theory-were also presented. In the case of MP2 level, the canonical and the local-correlation cases combined with the density-fitting technique (DF-LMP2)theories were considered, while for the dispersion-corrected DFT, the empirically-corrected BLYP-D and the M06-2Xexchange-correlation functionals were applied. In all cases, the aug-cc-pVTZ basis set was used, and the results were corrected for the basis set superposition error (BSSE) using the counterpoise method. For each molecular system, several dimer geometries were found, and their mutual orientations were compared with the nearest neighbor orientations obtained in recent neutron scattering studies. The nature of the intermolecular interaction energy was discussed.

Simultaneous determination of iodinated haloacetic acids and aromatic iodinated disinfection byproducts in waters with a new SPE-HPLC-MS/MS method.

Iodinated disinfection byproducts (DBPs) are an emerging category of halogenated DBPs in concern due to their high toxicity. Among them, polar iodinated DBPs, mainly including iodinated haloacetic acids (HAAs) and aromatic iodinated DBPs, were reported to be especially toxic. Thus, simultaneous determination of these polar iodinated DBPs in disinfected waters is of great significance for DBP studies. In this study, it was found that traditional liquid-liquid extraction, which was adopted for the determination of polar iodinated DBPs, was actually not suitable for the determination of monoiodoacetic acid (MIAA) and diiodoacetic acid (DIAA) due to the low recoveries, and thus a new SPE-HPLC-MS/MS method was developed for the simultaneous determination of iodinated HAAs and aromatic iodinated DBPs. The parameters for SPE pretreatment were optimized, including SPE cartridge, eluent volume, formic acid content in eluent, and sample pH before SPE. The new method was demonstrated to be sensitive and accurate with detection limits of 0.15, 0.04, 0.03, 0.02, 0.06, and 0.06 ng/L, quantitation limits of 0.48, 0.13, 0.10, 0.06, 0.19, and 0.19 ng/L, and precision of 8.3%, 6.0%, 12.3%, 8.8%, 11.4%, and 15.6% for MIAA, DIAA, 3,5-diiodo-4-hydroxybenzaldehyde, 3,5-diiodosalicylic acid, 2,6-diiodo-4-nitrophenol and 2,4,6-triiodophenol, respectively. The recoveries of these six polar iodinated DBPs were all in the range of 70-110%. The new method was applied to the determination of iodinated HAAs and aromatic iodinated DBPs in nine tap water samples, and they were detected with concentrations ranging from 0.03 to 3.97 ng/L, among which MIAA was detected in all the samples with the highest concentrations.

The influence of precursors and treatment process on the formation of Iodo-THMs in Canadian drinking water.

The National Survey of Disinfection By-Products and Selected Emerging Contaminants investigated the formation of various disinfection by-products and contaminants in 65 water treatment systems (WTSs) across Canada. Results for six iodo-trihalomethanes (iodo-THMs) are reported in this paper. The participating water treatment systems included large, medium and small systems using water sources and treatment processes which were representative of Canadian drinking water. Five water samples (source water, treated water and three water samples along the distribution system) were collected from each treatment system, both under winter and summer conditions. Samples were stabilized, shipped cold and analysed for six iodo-THMs (dichloroiodomethane-DCIM; dibromoiodomethane-DBIM; bromochloroiodomethane-BCIM; chlorodiiodomethane-CDIM; bromodiiodomethane-BDIM and triiodomethane or iodoform-TIM), using a SPME-GC-ECD method developed in our laboratory (MDLs from 0.02 µg/L for iodoform to 0.06 µg/L for bromodiiodomethane). Concentrations of relevant precursors like dissolved organic carbon (DOC), bromide, iodide and total iodine, as well as other water quality parameters, were also determined. Detailed information about the treatment process used at each location was recorded using a questionnaire. The survey showed that one or more iodo-THMs were detected at 31 out of 64 water treatment systems (WTSs) under winter conditions and in 46 out of 64 WTSs under summer conditions (analytical results from one site were excluded due to sampling challenges). Total iodo-THM concentrations measured during this survey ranged from 0.02 µg/L to 21.66 µg/L. The highest total iodo-THM concentration was measured in WTS 63 where all six iodo-THMs were detected and iodoform was present in the highest concentration. The highest iodo-THM formation was found to occur in treatment systems where water sources had naturally occurring ammonium as well as high bromide, high iodide and/or total iodine concentrations. In two such water systems the total concentration of iodo-THMs exceeded the concentration of regulated THMs.

Microbial metabolism directly affects trace gases in (sub) polar snowpacks.

Concentrations of trace gases trapped in ice are considered to develop uniquely from direct snow/atmosphere interactions at the time of contact. This assumption relies upon limited or no biological, chemical or physical transformations occurring during transition from snow to firn to ice; a process that can take decades to complete. Here, we present the first evidence of environmental alteration due to in situ microbial metabolism of trace gases (methyl halides and dimethyl sulfide) in polar snow. We collected evidence for ongoing microbial metabolism from an Arctic and an Antarctic location during different years. Methyl iodide production in the snowpack decreased significantly after exposure to enhanced UV radiation. Our results also show large variations in the production and consumption of other methyl halides, including methyl bromide and methyl chloride, used in climate interpretations. These results suggest that this long-neglected microbial activity could constitute a potential source of error in climate history interpretations, by introducing a so far unappreciated source of bias in the quantification of atmospheric-derived trace gases trapped within the polar ice caps.

Quantitative Mid-Infrared Cavity Ringdown Detection of Methyl Iodide for Monitoring Applications.

Methyl iodide is a toxic halocarbon with diverse industrial and agricultural applications, and it is an important ocean-derived trace gas that contributes to the iodine burden of the atmosphere. Quantitative analysis of CH3I is mostly based on gas chromatography coupled with mass spectrometry or electron capture detection (GC-MS/ECD) as of yet, which often limits the ability to conduct in situ high-frequency monitoring studies. This work presents an alternative detection scheme based on mid-infrared continuous wave cavity ringdown spectroscopy (mid-IR cw-CRDS). CH3I was detected at the RR2(15) rovibrational absorption transition at v = 3090.4289 cm-1; part of the corresponding v4 vibration band has been measured with Doppler-limited resolution for the first time. A line strength of S(T = 295 K) = (545 ± 20) cm/mol, corresponding to a line center absorption cross-section σc(p = 0 bar) = (1.60 ± 0.06) × 105 cm2/mol, and pressure-broadening coefficients γp(Ar) = (0.094 ± 0.002) cm-1/bar and γp(N2) = (0.112 ± 0.003) cm-1/bar have been determined. The performance of the detection system has been demonstrated with a tank-purging experiment and has been directly compared with a conventional GC-MS/ECD detection system. Quantitative detection with high reproducibility and continuous sampling is possible with a current noise-equivalent limit of detection of 15 ppb at 20 mbar absorption-cell pressure and 70 s averaging time. This limit of detection is suitable for practical applications in the ppm mixing ratio level range such as workplace monitoring, leak detection, and process studies. Natural environmental abundances are much lower, therefore possibilities for future improvement of the detection limit are discussed.

Spatio-temporal distributions of chlorofluorocarbons and methyl iodide in the Changjiang (Yangtze River) estuary and its adjacent marine area.

Temporal and spatial distribution patterns of volatile halogenated organic compounds (VHOCs), such as dichlorodifluoromethane (CFC-12), trichlorofluoromethane (CFC-11), trichlorotrifluoroethane (CFC-113), and methyl iodide (CH3I), in the Changjiang (Yangtze River) estuary and its adjacent marine area were measured during two cruises from 21 February to 10 March 2014 and from 10 to 21 July 2014. VHOC concentrations showed seasonal variation with higher values during winter. VHOC distributions evidently decreased along the freshwater plume from the river mouth to the open sea and from inshore to offshore regions. VHOC distributions were obviously influenced by the Changjiang runoff, anthropogenic inputs, and biological release of phytoplankton. The study area was a net sink for CFC-12 and CFC-11, but a net source for atmospheric CH3I during the study periods.

Identification, toxicity and control of iodinated disinfection byproducts in cooking with simulated chlor(am)inated tap water and iodized table salt.

Chlorine/chloramine residuals are maintained in drinking water distribution systems to prevent microbial contamination and microorganism regrowth. During household cooking processes (e.g., soup making), the residual chlorine/chloramines in tap water may react with the iodide in iodized table salt to form hypoiodous acid, which could react with remaining natural organic matter in tap water and organic matter in food to generate iodinated disinfection byproducts (I-DBPs). However, I-DBPs formed during cooking with chloraminated/chlorinated tap water are almost completely new to researchers. In this work, by adopting precursor ion scan of m/z 127 using ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, many new polar I-DBPs formed during cooking with chloraminated/chlorinated tap water were detected and proposed with structures, of which 3-iodo-4-hydroxybenzaldehyde, 3-iodo-4-hydroxybenzoic acid, 3-iodo-4-hydroxy-5-methylbenzoic acid, diiodoacetic acid, 3,5-diiodo-4-hydroxybenzaldehyde, 3,5-diiodo-4-hydroxybenzoic acid, 2,6-diiodo-4-nitrophenol, 2,4-diiodo-6-nitrophenol, and 2,4,6-triiodophenol were confirmed with standard compounds. With the aid of ultra fast liquid chromatography/ion trap-time of flight-mass spectrometry, molecular formula identification of five new I-DBPs (C8H5O4I, C7H4NO4I, C8H5O5I, C7H4NO5I, and C8H6O3I2) was achieved. A developmental toxicity with a recently developed sensitive bioassay was conducted for the newly identified I-DBPs, suggesting that phenolic I-DBPs (except for iodinated carboxyphenols) were about 50-200 times more developmentally toxic than aliphatic I-DBPs. The major I-DBPs in a baseline simulated cooking water sample were determined to be from 0.72 to 7.63 µg/L. Polar I-DBPs formed under various disinfection and cooking conditions were compared, and suggestions for controlling their formation were provided.

Modification by UV radiation of the surface of thin films based on collagen extracted from fish scales.

Collagen was extracted from fish scales (Esox lucius) through demineralization process. Thin films by solvent evaporation from collagen extracted from fish scales were prepared. The surface of thin films made of fish scales collagen was modified by ultraviolet (UV)-irradiation with the wavelength λ = 254 nm. The amino acid composition of the Esox lucius scale collagen was analyzed before and after UV-irradiation by means of high-pressure liquid chromatography. The surface properties of films were investigated using the technique of atomic force microscopy (AFM) and by means of contact angle measurements allowing the calculation of surface free energy. Measurements of the contact angle for diiodomethane (D) and glycerol (G) on the surface of fish collagen films were made and surface free energy was calculated. The structure of collagen before and after UV-irradiation was studied using Fourier-transform infrared spectroscopy. It was found that after UV-irradiation the amount of all amino acids present in collagen molecule decreased. It was found also that the contact angle and the surface free energy were altered by UV-irradiation of collagen film. AFM showed that the surface roughness of collagen films was also altered by UV-irradiation. UV-irradiation caused the decrease of surface roughness due to photochemical processes, which occurred in the top layer of collagen film. The formation of collagen fibrils after solvent evaporation was observed using AFM. The diameter of collagen fibrils was bigger for irradiated collagen film than the diameter of collagen fibrils before UV-irradiation.

Gas chromatographic-mass spectrometric quantitation of busulfan in human plasma for therapeutic drug monitoring: a new on-line derivatization procedure for the conversion of busulfan to 1,4-diiodobutane.

A simplified gas chromatographic-mass spectrometric (GC-MS) analytical method, involving a novel derivatization procedure was developed for monitoring busulfan (Bu) plasma concentrations in populations undergoing bone marrow transplantation. Plasma samples (500 µL) containing Bu-d8 as internal standard were extracted with ethyl acetate (2 mL) followed by centrifugation (1800 rpm, 5 min) and evaporation of the organic layer under nitrogen flow (50 °C). The dry residue was reconstituted with 100 µL iodine solution in acetonitrile (0.25%, w/v) and 3 µL were injected into the GC-MS system at 250 °C. Conversion of Bu to 1,4-diiodobutane was accomplished on-line without the need of an extra derivatization step. MS was operated at selected ion monitoring mode at m/z 183 and 191 corresponding to Bu and Bu-d8 derivatives. Total analysis time was 11.5 min. Calibration curves were linear (mean r=0.9996) over a concentration range of 25-3651 ng/mL using a (1/x)-weighted scheme. Limit of detection and lower limit of quantitation were 10.6 and 25 ng/mL, respectively. Overall accuracy Er (%) was ranging from -5.10% to 10.5%. Within- and between-run RSD (%) were lower 4.51% and 2.15%, respectively. Overall recovery of Bu was equal to 69.3±4.56% (RSD (%)). The present method is sensitive and specific, requiring a simple sample preparation procedure and short analysis time, advantages crucial for therapeutic drug monitoring of Bu in clinical practice and application in pharmacokinetic studies.

Mitigating iodomethane emissions and iodide residues in fumigated soils.

Although long-regarded as an excellent soil fumigant for killing plant pests, methyl bromide (MeBr) was phased out in 2005 in the USA, because it can deplete the stratospheric ozone layer. Iodomethane (MeI) has been identified as an effective alternative to MeBr and is used in a number of countries for preplant pest control. However, MeI is highly volatile and potentially carcinogenic to humans if inhaled. In addition, iodide anions, a breakdown product of MeI, can build up in fumigated soils and potentially cause plant toxicity and contaminate groundwater via leaching. In order to overcome the above two obstacles in MeI application, a method is proposed to place reactive bags containing ammonium hydroxide solution (NH4OH) on the soil surface underneath an impermeable plastic film covering the fumigated area. Our research showed that using this approach, over 99% of the applied MeI was quantitatively transferred to iodide. Of all the resulting iodide, only 2.7% remained in the fumigated soil, and 97.3% was contained in the reactive bag that can be easily removed after fumigation.

Drinking water disinfection byproduct iodoacetic acid induces tumorigenic transformation of NIH3T3 cells.

Iodoacetic acid (IAA) and iodoform (IF) are unregulated iodinated disinfection byproducts (DBPs) found in drinking water. Their presence in the drinking water of China has not been documented. Recently, the carcinogenic potential of IAA and IF has been a concern because of their mutagenicity in bacteria and genotoxicity in mammalian cells. Therefore, we measured their concentrations in Shanghai drinking water and assessed their cytotoxicity, genotoxicity, and ability to transform NIH3T3 cells to tumorigenic lines. The concentrations of IAA and IF in Shanghai drinking water varied between summer and winter with maximum winter levels of 2.18 µg/L IAA and 0.86 µg/L IF. IAA with a lethal concentration 50 (LC50) of 2.77 µM exhibited more potent cytotoxicity in NIH3T3 cells than IF (LC50 = 83.37 µM). IAA, but not IF, induced a concentration-dependent DNA damage measured by γ-H2AX staining and increased tail moment in single-cell gel electrophoresis. Neither IAA nor IF increased micronucleus frequency. Prolonged exposure of NIH3T3 cells to IAA increased the frequencies of transformed cells with anchorage-independent growth and agglutination with concanavalin A. IAA-transformed cells formed aggressive fibrosarcomas after inoculation into Balb/c nude mice. This study demonstrated that IAA has a biological activity that is consistent with a carcinogen and human exposure should be of concern.

An optimized analytical method for the simultaneous detection of iodoform, iodoacetic acid, and other trihalomethanes and haloacetic acids in drinking water.

An optimized method is presented using liquid-liquid extraction and derivatization for the extraction of iodoacetic acid (IAA) and other haloacetic acids (HAA9) and direct extraction of iodoform (IF) and other trihalomethanes (THM4) from drinking water, followed by detection by gas chromatography with electron capture detection (GC-ECD). A Doehlert experimental design was performed to determine the optimum conditions for the five most significant factors in the derivatization step: namely, the volume and concentration of acidic methanol (optimized values  = 15%, 1 mL), the volume and concentration of Na2SO4 solution (129 g/L, 8.5 mL), and the volume of saturated NaHCO3 solution (1 mL). Also, derivatization time and temperature were optimized by a two-variable Doehlert design, resulting in the following optimized parameters: an extraction time of 11 minutes for IF and THM4 and 14 minutes for IAA and HAA9; mass of anhydrous Na2SO4 of 4 g for IF and THM4 and 16 g for IAA and HAA9; derivatization time of 160 min and temperature at 40°C. Under optimal conditions, the optimized procedure achieves excellent linearity (R(2) ranges 0.9990-0.9998), low detection limits (0.0008-0.2 µg/L), low quantification limits (0.008-0.4 µg/L), and good recovery (86.6%-106.3%). Intra- and inter-day precision were less than 8.9% and 8.8%, respectively. The method was validated by applying it to the analysis of raw, flocculated, settled, and finished waters collected from a water treatment plant in China.

Formation of iodinated disinfection by-products during oxidation of iodide-containing water with potassium permanganate.

This study shows that iodinated disinfection by-products (I-DBPs) including iodoform (IF), iodoacetic acid (IAA) and triiodoacetic acid (TIAA) can be produced when iodide-containing waters are in contact with potassium permanganate. IF was found as the major I-DBP species during the oxidation. Iodide was oxidized to HOI, I(2) and I(3)(-), consequently, which led to the formation of iodinated organic compounds. I-DBPs varied with reaction time, solution pH, initial concentrations of iodide and potassium permanganate. Yields of IF, IAA and TIAA increased with reaction time and considerable I-DBPs were formed within 12 h. Peak IF yields were found at circumneutral pH range. However, formation of IAA and TIAA was favored under acidic conditions. Molar ratio of iodide to potassium permanganate showed significant influence on formation of IF, IAA and TIAA. The formation of IF, IAA and TIAA also depended on the characteristics of the waters.

Mitigating 1,3-dichloropropene, chloropicrin, and methyl iodide emissions from fumigated soil with reactive film.

Implicated as a stratospheric ozone-depleting compound, methyl bromide (MeBr) is being phased out despite being considered to be the most effective soil fumigant. Its alternatives, i.e., 1,3-dichloropropene (1,3-D, which includes cis and trans isomers), chloropicrin (CP), and methyl iodide (MeI), have been widely used. High emissions of MeI from fumigated soil likely put farm workers and other bystanders at risk of adverse health effects. In this study, two types of constructed reactive film were tested for their ability to mitigate emissions of 1,3-D, CP, and MeI using laboratory permeability cells. Before activation, these films act as a physical barrier to trap fumigants leaving soil. After activation of the reactive layer containing ammonium thiosulfate solution, the films also act as a sink for the fumigants. Over 97% of trans-1,3-D and 99% of the cis-1,3-D, CP and MeI were depleted when they passed into the reactive film. Half-lives (t(1/2)) of cis-, trans-1,3-D, CP and MeI under activated reactive film were 1.2, 1.4, 1.6, and 2.0 h respectively at 40 °C.

Three spectroscopic techniques evaluated as a tool to study the effects of iodination of monoclonal antibodies, exemplified by rituximab.

Radioiodinated monoclonal antibodies have been used for radioimmunotherapeutic and radiodiagnostic purposes. Radioiodination of monoclonal antibodies may lead to deterioration of the immunoreactivity of the monoclonal antibody. Methods for the determination of the immunoreactivity, however, do not provide information about any structural changes of the radioconjugate which may influence the binding properties of the protein to the target antigen. Within this study we demonstrated the potential role of three alternative spectroscopic analytical techniques to characterize the structural changes emerging after iodination of rituximab. We conclude that techniques as liquid chromatography coupled to mass spectrometry, fluorescence emission spectrophotometry, and circular dichroism can provide valuable information about structural changes of a radiolabeled compound, e.g. during pharmaceutical development and for quality control.

Formation of organic iodine supplied as iodide in a soil-water system in Chiba, Japan.

Speciation of iodine in a soil-water system was investigated to understand the mechanism of iodine mobility in surface environments. Iodine speciation in soil and pore water was determined by K-edge XANES and HPLC-ICP-MS, respectively, for samples collected at a depth of 0-12 cm in the Yoro area, Chiba, Japan. Pore water collected at a 0-6 cm depth contained 50%-60% of organic iodine bound to dissolved organic matter, with the other portion being I(-). At a 9-12 cm depth, 98% of iodine was in the form of dissolved I(-). In contrast, XANES analysis revealed that iodine in soil exists as organic iodine at all depths. Iodine mapping of soil grains was obtained using micro-XRF analysis, which also indicated that iodine is bound to organic matter. The activity of laccase, which has the ability to oxidize I(-) to I(2), was high at the surface of the soil-water layer, suggesting that iodide oxidizing enzymes can promote iodine organification. The distribution coefficient of organic iodine in the soil-water system was more than 10-fold greater than that of iodide. Transformation of inorganic iodine to organic iodine plays an important role in iodine immobilization, especially in a surface soil-water system.

Isolation and characterization of a gene encoding a S-adenosyl-l-methionine-dependent halide/thiol methyltransferase (HTMT) from the marine diatom Phaeodactylum tricornutum: Biogenic mechanism of CH(3)I emissions in oceans.

Several marine algae including diatoms exhibit S-adenosyl-l-methionine (SAM) halide/thiol methyltransferase (HTMT) activity, which is involved in the emission of methyl halides. In this study, the in vivo biogenic emission of methyl iodide from the diatom Phaeodactylum tricornutum was found to be clearly correlated with iodide concentration in the incubation media. The gene encoding HTMT (Pthtmt) was isolated from P. tricornutum CCAP 1055/1, and expressed in Escherichia coli. The molecular weight of the enzyme was 29.7kDa including a histidine tag, and the optimal pH was around pH 7.0. The kinetic properties of recombinant PtHTMT towards Cl(-), Br(-), I(-), [SH](-), [SCN](-), and SAM were 637.88mM, 72.83mM, 8.60mM, 9.92mM, 7.9mM, and 0.016mM, respectively, and were similar to those of higher-plant HTMTs, except that the activity towards thiocyanate was lower. The biogenic emission of methyl halides from the cultured cells and the enzymatic properties of HTMT suggest that the HMT/HTMT reaction is key to understanding the biogenesis of methyl halides in oceanic environments as well as terrestrial ones.

Irrigation, organic matter addition, and tarping as methods of reducing emissions of methyl iodide from agricultural soil.

Methyl iodide (MeI) is increasingly being used as a highly effective alternative to the soil fumigant methyl bromide. Due to its volatile and toxic nature, MeI draws wide attention on its potential atmospheric emission following field fumigation treatment. Using soil columns that make it possible to determine emissions and gas phase distribution of soil fumigants, we studied MeI behavior in two soils differing in organic matter content. Additionally, the effectiveness of surface irrigation and tarping with virtually impermeable film (VIF) was assessed. In the lower organic matter, bare soil (control), emissions of MeI were rapid and high (83% of total). Although the peak emission flux was reduced by irrigation, the total loss was very similar to the control (82%). Tarping with VIF dramatically reduced emissions (0.04% total emissions). In the higher organic matter soil, degradation rate of MeI was increased around 4-fold, leading to a significant reduction in emissions (63% total emissions). The work suggests that surface tarping with VIF would be highly effective as an emissions reduction strategy and would also result in the maintenance of high soil gas concentrations (important for pest control). Ripping of the tarp after two weeks led to an immediate spike release of MeI, but, even so, the flux rate at this time was almost 20 times lower than the peak flux rate in the control. Even with tarp ripping, the total emission loss from the VIF treatment remained low (6%).

Variability in the proportion of components of iodoform-based Guedes-Pinto paste mixed by dental students and pediatric dentists.

OBJECTIVE: Guedes-Pinto paste (GPP) is an iodoform paste used in most dental schools in Brazil. The paste is a composite of medicines (Rifocort , camphorated paramonochlorophenol [PMCC], and iodoform) used for endodontic treatment of primary teeth. The aim of this study was to evaluate the proportion variability of GPP components when mixed by undergraduate dentistry students and pediatric dentists. MATERIALS AND METHODS: The study was divided into 4 groups: G1 (15 undergraduate students), G2 (15 specialists in Pediatric Dentistry), G3 (15 professors with clinical activity), and G4 (7 professors-researchers). All volunteers prepared GPP according to the original specifications: the same visual proportion for each component. The components were weighed using an analytical balance and the percentage was calculated. RESULT: After normality (Kolmogorov-Smirnov) and homogeneity tests (Levene test), the data were submitted to analysis of variance and intraclass correlation coefficient tests (P<0.05). The percentage means of each respective group were as follows: Rifocort 20.2%, 20.8%, 26.7%, 27.3%; camphorated PMCC 9.2%, 8.1%, 6.7%, 5.1%; and the iodoform 70.6%, 71.1%, 64.7%, 67.6%. There were no significant differences between groups for the component percentages. There was a high intraclass correlation coefficient (G1 0.945; G2 0.951; G3 0.921; and G4 0.870). CONCLUSION: The proportion of GPP was similar in all the groups, allowing us to conclude that ideal GPP proportion, based on the entire group mean, was 23.8% of Rifocort® ; 7.0% of camphorated PMCC; and 69.2% of iodoform.

A novel approach for the simultaneous determination of iodide, iodate and organo-iodide for 127I and 129I in environmental samples using gas chromatography-mass spectrometry.

In aquatic environments, iodine mainly exists as iodide, iodate, and organic iodine. The high mobility of iodine in aquatic systems has led to (129)I contamination problems at sites where nuclear fuel has been reprocessed, such as the F-area of Savannah River Site. In order to assess the distribution of (129)I and stable (127)I in environmental systems, a sensitive and rapid method was developed which enables determination of isotopic ratios of speciated iodine. Iodide concentrations were quantified using gas chromatography-mass spectrometry (GC-MS) after derivatization to 4-iodo-N,N-dimethylaniline. Iodate concentrations were quantified by measuring the difference of iodide concentrations in the solution before and after reduction by Na(2)S(2)O(5). Total iodine, including inorganic and organic iodine, was determined after conversion to iodate by combustion at 900 °C. Organo-iodine was calculated as the difference between the total iodine and total inorganic iodine (iodide and iodate). The detection limits of iodide-127 and iodate-127 were 0.34 nM and 1.11 nM, respectively, whereas the detection limits for both iodide-129 and iodate-129 was 0.08 nM (i.e., 2pCi (129)I/L). This method was successfully applied to water samples from the contaminated Savannah River Site, South Carolina, and more pristine Galveston Bay, Texas.