Ionic Liquids for the Separation of Fluorocarbon Refrigerant Mixtures.

This review discusses the research being performed on ionic liquids for the separation of fluorocarbon refrigerant mixtures. Fluorocarbon refrigerants, invented in 1928 by Thomas Midgley Jr., are a unique class of working fluids that are used in a variety of applications including refrigeration. Fluorocarbon refrigerants can be categorized into four generations: chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, and hydrofluoroolefins. Each generation of refrigerants solved a key problem from the previous generation; however, each new generation has relied on more complex mixtures that are often zeotropic, near azeotropic, or azeotropic. The complexity of the refrigerants used and the fact that many refrigerants form azeotropes when mixed makes handling the refrigerants at end of life extremely difficult. Today, less than 3% of refrigerants that enter the market are recycled. This is due to a lack of technology in the refrigerant reclaim market that would allow for these complex, azeotropic refrigerant mixtures to be separated into their components in order to be effectively reused, recycled, and if needed repurposed. As the market for recovering and reclaiming refrigerants continues to grow, there is a strong need for separation technology. Ionic liquids show promise for separating azeotropic refrigerant mixtures as an entrainer in extractive distillation process. Ionic liquids have been investigated with refrigerants for this application since the early 2000s. This review will provide a comprehensive summary of the physical property measurements, equations of state modeling, molecular simulations, separation techniques, and unique materials unitizing ionic liquids for the development of an ionic-liquid-based separation process for azeotropic refrigerant mixtures.

Comparison of transforaminal lumbar interbody fusion outcomes in patients receiving rhBMP-2 versus autograft.

BACKGROUND CONTEXT: Recombinant human bone morphogenetic protein 2 (rhBMP-2) plays a pivotal role in complex spine surgery. Despite its limited approval, the off-label use of rhBMP-2 is prevalent, particularly in transforaminal lumbar interbody fusions (TLIFs). PURPOSE: To determine the effectiveness and safety of rhBMP-2 use in TLIF procedures versus autograft. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Patients older than 18 years undergoing spine surgery for lumbar degenerative spine disease at a single academic institution. OUTCOME MEASURES: Clinical outcome was determined according to patient records. Radiographic outcome was determined according to plain X-rays and computed tomography (CT). METHODS: A retrospective study from 1997 to 2014 was conducted on 191 adults undergoing anterior-posterior instrumented spinal fusion with TLIF at a single academic institution. Patient data were gathered from operative notes, follow-up clinic notes, and imaging studies to determine complications and fusion rates. One hundred eighty-seven patients fit the criteria, which included patients with a minimum of one TLIF, and had a minimum 2-year radiographic and clinical follow-up. Patients were further classified into a BMP group (n=83) or non-BMP group (n=104). Three logistic regression models were run using rhBMP-2 exposure as the independent variable. The respective outcome variables were TLIF-related complications (radiculitis, seroma, osteolysis, and ectopic bone), surgical complications, and all complications. RESULTS: Bone morphogenetic protein (n=83) and non-BMP (n=104) groups had similar baseline demographics (sex, diabetes, pre-existing cancer). On average, the BMP and non-BMP groups were similarly aged (51.9 vs. 47.9 years, p>.05), but the BMP group had a shorter follow-up time (3.03 vs. 4.06 years; p<.001) and fewer smokers (8 vs. 21 patients; p<.048). The fusion rate for the BMP and non-BMP groups was 92.7% and 92.3%, respectively. The pseudoarthrosis rate was 7.5% (14 of 187 patients). Radiculitis was observed in seven patients in the BMP group (8.4%) and two patients in the non-BMP group (1.9%). Seroma was observed in two patients in the BMP group (2.4%) and none in the non-BMP group. No deep infections were observed in the BMP group, and in one patient in the non-BMP group (0.96%). Although patients exposed to BMP were at a significantlygreater risk of developing radiculitis and seroma (odds ratio [OR]=4.53, confidence interval [CI]=1.42-14.5), BMP exposure was not a significant predictor of surgical complications (OR=0.32, CI=0.10-1.00) or overall complications (OR=1.11, CI=0.53-2.34). The outcome of TLIF-related complications was too rare and the confidence interval too wide for practical significance of the first model. CONCLUSION: Evidence supports the hypothesis that off-label use of rhBMP-2 in TLIF procedures is relatively effective for achieving bone fusion at rates similar to patients receiving autograft. Patients exhibited similar complication rates between the two groups, with the BMP group exhibiting slightly higher rates of radiculitis and seroma.

Combining stable isotopes with contamination indicators: A method for improved investigation of nitrate sources and dynamics in aquifers with mixed nitrogen inputs.

Excessive nitrate (NO3-) concentration in groundwater raises health and environmental issues that must be addressed by all European Union (EU) member states under the Nitrates Directive and the Water Framework Directive. The identification of NO3- sources is critical to efficiently control or reverse NO3- contamination that affects many aquifers. In that respect, the use of stable isotope ratios 15N/14N and 18O/16O in NO3- (expressed as δ15N-NO3- and δ18O-NO3-, respectively) has long shown its value. However, limitations exist in complex environments where multiple nitrogen (N) sources coexist. This two-year study explores a method for improved NO3- source investigation in a shallow unconfined aquifer with mixed N inputs and a long established NO3- problem. In this tillage-dominated area of free-draining soil and subsoil, suspected NO3- sources were diffuse applications of artificial fertiliser and organic point sources (septic tanks and farmyards). Bearing in mind that artificial diffuse sources were ubiquitous, groundwater samples were first classified according to a combination of two indicators relevant of point source contamination: presence/absence of organic point sources (i.e. septic tank and/or farmyard) near sampling wells and exceedance/non-exceedance of a contamination threshold value for sodium (Na+) in groundwater. This classification identified three contamination groups: agricultural diffuse source but no point source (D+P-), agricultural diffuse and point source (D+P+) and agricultural diffuse but point source occurrence ambiguous (D+P±). Thereafter δ15N-NO3- and δ18O-NO3- data were superimposed on the classification. As δ15N-NO3- was plotted against δ18O-NO3-, comparisons were made between the different contamination groups. Overall, both δ variables were significantly and positively correlated (p < 0.0001, rs = 0.599, slope of 0.5), which was indicative of denitrification. An inspection of the contamination groups revealed that denitrification did not occur in the absence of point source contamination (group D+P-). In fact, strong significant denitrification lines occurred only in the D+P+ and D+P± groups (p < 0.0001, rs > 0.6, 0.53 ≤ slope ≤ 0.76), i.e. where point source contamination was characterised or suspected. These lines originated from the 2-6‰ range for δ15N-NO3-, which suggests that i) NO3- contamination was dominated by an agricultural diffuse N source (most likely the large organic matter pool that has incorporated 15N-depleted nitrogen from artificial fertiliser in agricultural soils and whose nitrification is stimulated by ploughing and fertilisation) rather than point sources and ii) denitrification was possibly favoured by high dissolved organic content (DOC) from point sources. Combining contamination indicators and a large stable isotope dataset collected over a large study area could therefore improve our understanding of the NO3- contamination processes in groundwater for better land use management. We hypothesise that in future research, additional contamination indicators (e.g. pharmaceutical molecules) could also be combined to disentangle NO3- contamination from animal and human wastes.

A one-step method for priority compounds of concern in tar from former industrial sites: trimethylsilyl derivatisation with comprehensive two-dimensional gas chromatography.

A dense non-aqueous phase liquid sample formed by release of coal tar into the environment was derivatised by trimethylsilylation using the reagent N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and extracted in hexane using accelerated solvent extraction. This procedure enables comprehensive extraction of an extensive suite of organic compounds from tar, which has not previously been described. Comprehensive two dimensional gas chromatography coupled to time of flight mass spectrometry (GC×GC-TOFMS) was used for the analysis of the sample for concurrent evaluation of -OH functional group-containing compounds along with aliphatics, polycyclic aromatic hydrocarbons and other typical tar compounds normally determined via classic gas chromatography. Using statistically designed experiments, a range of conditions were tested for complete recovery of four different surrogates. The robustness and repeatability of the optimised derivatisation/extraction method was demonstrated. Finally, more than a hundred and fifty derivatised compounds were identified using mass spectra elucidation and GC×GC logical order of elution.

Evaluating the utility of 15N and 18O isotope abundance analyses to identify nitrate sources: A soil zone study.

(15)N and (18)O isotope abundance analyses in nitrate (NO(3)(-)) (expressed as δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) values respectively) have often been used in research to help identify NO(3)(-) sources in rural groundwater. However, questions have been raised over the limitations as overlaps in δ values may occur between N source types early in the leaching process. The aim of this study was to evaluate the utility of using stable isotopes for nitrate source tracking through the determination of δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) in the unsaturated zone from varying N source types (artificial fertiliser, dairy wastewater and cow slurry) and rates with contrasting isotopic compositions. Despite NO(3)(-) concentrations being often elevated, soil-water nitrate poorly mirrored the (15)N content of applied N and therefore, δ(15)N-NO(3)(-) values were of limited assistance in clearly associating nitrate leaching with N inputs. Results suggest that the mineralisation and the nitrification of soil organic N, stimulated by previous and current intensive management, masked the cause of leaching from the isotopic prospective. δ(18)O-NO(3)(-) was of little use, as most values were close to or within the range expected for nitrification regardless of the treatment, which was attributed to the remineralisation of nitrate assimilated by bacteria (mineralisation-immobilisation turnover or MIT) or plants. Only in limited circumstances (low fertiliser application rate in tillage) could direct leaching of synthetic nitrate fertiliser be identified (δ(15)N-NO(3)(-)<0‰ and δ(18)O-NO(3)(-)>15‰). Nevertheless, some useful differences emerged between treatments. δ(15)N-NO(3)(-) values were lower where artificial fertiliser was applied compared with the unfertilised controls and organic waste treatments. Importantly, δ(15)N-NO(3)(-) and δ(18)O-NO(3)(-) variables were negatively correlated in the artificial fertiliser treatment (0.001≤p≤0.05, attributed to the varying proportion of fertiliser-derived and synthetic nitrate being leached) while positively correlated in the dairy wastewater plots (p≤0.01, attributed to limited denitrification). These results suggest that it may be possible to distinguish some nitrate sources if analysing correlations between δ variables from the unsaturated zone. In grassland, the above correlations were related to N input rates, which partly controlled nitrate concentrations in the artificial fertiliser plots (high inputs translated into higher NO(3)(-) concentrations with an increasing proportion of fertiliser-derived and synthetic nitrate) and denitrification in the dairy wastewater plots (high inputs corresponded to more denitrification). As a consequence, nitrate source identification in grassland was more efficient at higher input rates due to differences in δ values widening between treatments.

A multi-site analysis of the association between black carbon concentrations and vehicular idling, traffic, background pollution, and meteorology during school dismissals.

A study was performed to assess the relationship between black carbon (BC), passing traffic, and vehicular idling outside New York City (NYC) schools during student dismissal. Monitoring was performed at three school sites in East Harlem, the Bronx, and Brooklyn for 1month per year over a two-year period from November 2006-October 2008. Monitoring at each site was conducted before and after the Asthma Free School Zone (AFSZ) asthma reduction education program was administered. Real-time equipment with a one-minute averaging interval was used to obtain the BC data, while volume counts of idling and passing school busses, trucks, and automobiles were collected each minute by study staff. These data were matched to ambient PM(2.5) and meteorology data obtained from the New York State Department of Environmental Conservation. A generalized additive model (GAM) model was run to examine the relationship between BC concentration and each variable while accounting for site-to-site differences. F-tests were employed to assess the significance of each of the predictor variables. The model results suggested that variability in ambient PM(2.5) concentration contributed 24% of the variability in transformed BC concentration, while variability in the number of idling busses and trucks on the street during dismissal contributed 20% of the variability in transformed BC concentration. The results of this study suggest that a combination of urban scale and local traffic control approaches in combination with cessation of school bus idling will produce improved local BC concentration outside schools.

Ten year performance evaluation of a field-scale zero-valent iron permeable reactive barrier installed to remediate trichloroethene contaminated groundwater.

The Monkstown zero-valent iron permeable reactive barrier (ZVI PRB), Europe's oldest commercially-installed ZVI PRB, had been treating trichloroethene (TCE) contaminated groundwater for about 10 years on the Nortel Network site in Northern Ireland when cores from the reactive zone were collected in December, 2006. Groundwater data from 2001-2006 indicated that TCE is still being remediated to below detection limits as the contaminated groundwater flows through the PRB. Ca and Fe carbonates, crystalline and amorphous Fe sulfides, and Fe (hydr)oxides have precipitated in the granular ZVI material in the PRB. The greatest variety of minerals is associated with a approximately 1-2 cm thick, slightly cemented crust on top (up-gradient influent entrance) of the ZVI section of the PRB and also with the discontinuous cemented ZVI material ( approximately 23 cm thick) directly below it. The greatest presence of microbial communities also occurred in the up-gradient influent portion of the PRB compared to its down-gradient effluent section, with the latter possibly due to less favorable conditions (i.e., high pH, low oxygen) for microbial growth. The ZVI filings in the down-gradient effluent section of the PRB have a projected life span of >10 years compared with ZVI filings from the continuous to discontinuous cemented up-gradient ZVI section (upper approximately 25 cm) of the PRB, which may have a life span of only approximately 2-5 more years. Supporting Information from applied, multi-tracer testing indicated that restricted groundwater flow is occurring in the upper approximately 25 cm of the ZVI section and preferential pathways have also formed in this PRB over its 10 years of operation.

Detection of avian metapneumovirus subtypes in turkeys using RT-PCR.

This study investigated the prevalence of avian metapneumovirus (aMPV) and the detection of molecular subtypes of field strains of the virus using RT-PCR in clinically healthy turkeys and those showing signs of respiratory disease. In the RT-PCR examination of 624 tracheal tissue samples collected from a local turkey abattoir, 2.9 per cent (18/624) of samples tested positive. In the examination of tracheal swab samples collected from flocks with respiratory problems, 18 of 20 samples tested positive. When the results were assessed at flock level, aMPV infection was detected in only one of the 23 clinically healthy turkey flocks, whereas all four flocks with respiratory problems were infected. Molecular typing using primers specific to the attachment glycoprotein (G) gene showed that all 36 positive samples belonged to subtype B. Partial sequence analysis of DNA samples showed 95 per cent homology between the field types and the reference strain aMPV subtype B. Whereas clinically healthy turkeys had been vaccinated with a subtype A virus vaccine, the flocks with respiratory problems had been vaccinated with a subtype B virus vaccine. Despite four blind passages of RT-PCR-positive samples on Vero and chicken embryo fibroblast cells, no cytopathic effect was detected by microscopic examination.

Gliomas induce and exploit microglial MT1-MMP expression for tumor expansion.

Diffuse infiltration of glioma cells into normal brain tissue is considered to be a main reason for the unfavorable outcomes of patients with malignant gliomas. Invasion of glioma cells into the brain parenchyma is facilitated by metalloprotease-mediated degradation of the extracellular matrix. Metalloproteases are released as inactive pro-forms and get activated upon cleavage by membrane bound metalloproteases. Here, we show that membrane type 1 metalloprotease (MT1-MMP) is up-regulated in glioma-associated microglia, but not in the glioma cells. Overexpression of MT1-MMP is even lethal for glioma cells. Glioma-released factors trigger the expression and activity of MT1-MMP via microglial toll-like receptors and the p38 MAPK pathway, as deletion of the toll-like receptor adapter protein MyD88 or p38 inhibition prevented MT1-MMP expression and activity in cultured microglial cells. Microglial MT1-MMP in turn activates glioma-derived pro-MMP-2 and promotes glioma expansion, as shown in an ex vivo model using MT1-MMP-deficient brain tissue and a microglia depletion paradigm. Finally, MyD88 deficiency or microglia depletion largely attenuated glioma expansion in 2 independent in vivo models.

Associations of PM2.5 and black carbon concentrations with traffic, idling, background pollution, and meteorology during school dismissals.

An air quality study was performed outside a cluster of schools in the East Harlem neighborhood of New York City. PM(2.5) and black carbon concentrations were monitored using real-time equipment with a one-minute averaging interval. Monitoring was performed at 1:45-3:30 PM during school days over the period October 31-November 17, 2006. The designated time period was chosen to capture vehicle emissions during end-of-day dismissals from the schools. During the monitoring period, minute-by-minute volume counts of idling and passing school buses, diesel trucks, and automobiles were obtained. These data were transcribed into time series of number of diesel vehicles idling, number of gasoline automobiles idling, number of diesel vehicles passing, and number of automobiles passing along the block adjacent to the school cluster. Multivariate regression models of the log-transform of PM(2.5) and black carbon (BC) concentrations in the East Harlem street canyon were developed using the observation data and data from the New York State Department of Environmental Conservation on meteorology and background PM(2.5). Analysis of variance was used to test the contribution of each covariate to variability in the log-transformed concentrations as a means to judge the relative contribution of each covariate. The models demonstrated that variability in background PM(2.5) contributes 80.9% of the variability in log[PM(2.5)] and 81.5% of the variability in log[BC]. Local traffic sources were demonstrated to contribute 5.8% of the variability in log[BC] and only 0.43% of the variability in log[PM(2.5)]. Diesel idling and passing were both significant contributors to variability in log[BC], while diesel passing was a significant contributor to log[PM(2.5)]. Automobile idling and passing did not contribute significant levels of variability to either concentration. The remainder of variability in each model was explained by temperature, along-canyon wind, and cross-canyon wind, which were all significant in the models.

Detection of contagious caprine pleuropneumonia in East Turkey.

A study was implemented to investigate the presence of contagious caprine pleuropneumonia (CCPP) in East Turkey. This study was based on clinical surveillance in the field, surveillance at regional slaughterhouses and regular submission of suspected lesions to regional laboratories. The results showed that the agent of CCPP, Mycoplasma capricolum subspecies capripneumoniae (Mccp), could be detected by culture and specific polymerase chain reaction from 37.5% (12/32) of lung samples taken from goats of ten different herds. This agent was also isolated from two of 13 sheep samples (one from the lung and the other from a nasal swab). Mycoplasma capricolum subsp. capripneumoniae was isolated in pure culture and characterised at a finer molecular level. The East Turkish isolate was found to be closely related to another strain of Turkish origin, as well as to Mccp strains isolated in Tunisia. The isolation of Mccp from sheep lung lesions brings the strict host-specificity of this pathogen into question. It may also indicate that Mccp presents a risk for wildlife in the region. Such results, the authors believe, demonstrate that adequate risk assessments should be undertaken in Turkey and neighbouring countries.

Detection of mycoplasma species in turkeys by culture and polymerase chain reaction.

The purpose of the present study was to investigate the presence of pathogenic mycoplasma species in the turkey population of Turkey. Tracheal samples randomly collected from a total of 624 apparently healthy meat-type turkeys at a commercial abattoir located in the north of the country were examined by culture and genus- and species-specific polymerase chain reaction (PCR) assays for mycoplasma. In the direct plating onto solid specific media, mycoplasma growth was observed from 1.4% (9/624) of the samples, which were confirmed to belong to the Mycoplasma genus by genus-specific PCR. Mycoplasma iowae (MI) and M. meleagridis (MM) were identified by the species-specific PCR from eight and one of the samples, respectively. However, genus-specific PCR amplification was obtained from 2.6% (16/624) of the samples which produced turbidity in the liquid media. Interestingly, these positive samples were different from those obtained from solid agar and mycoplasma growth was not observed when the broth samples were inoculated onto solid media. In the species-specific PCR analysis of the broth samples, MI, MM and M. gallisepticum were identified from twelve, two and two samples, respectively. The inconsistency between the results obtained from liquid and solid media raises questions about the efficiency of isolation procedures for mycoplasma and this warrants further investigation.

Forensic analysis of wooden safety matches -- a case study.

In this case, an individual was suspected of attempting to burn materials potentially relating to a murder case. A number of spent and unspent matches were seized at the scene by police for forensic examination. Coincidentally, a police raid at the suspect's house revealed a number of matchboxes, all of the same brand, containing matches that had a visual similarity to those recovered at the scene. Stable Isotope Profiling (SIP) was used to assess whether matches could either be distinguished or shown to be indistinguishable by 13C and 2H isotopic composition. These results were then compared to those from the X-ray diffraction (XRD) analysis of match heads and microscopy of the wood. SIP showed the scene matches and seized matches to be different, which was confirmed by XRD and microscopy analyses.

Microbial analysis of soil and groundwater from a gasworks site and comparison with a sequenced biological reactive barrier remediation process.

AIMS: To investigate the distribution of a polymicrobial community of biodegradative bacteria in (i) soil and groundwater at a former manufactured gas plant (FMGP) site and (ii) in a novel SEquential REactive BARrier (SEREBAR) bioremediation process designed to bioremediate the contaminated groundwater. METHODS AND RESULTS: Culture-dependent and culture-independent analyses using denaturing gradient gel electrophoresis (DGGE) and polymerase chain reaction (PCR) for the detection of 16S ribosomal RNA gene and naphthalene dioxygenase (NDO) genes of free-living (planktonic groundwater) and attached (soil biofilm) samples from across the site and from the SEREBAR process was applied. Naphthalene arising from groundwater was effectively degraded early in the process and the microbiological analysis indicated a dominant role for Pseudomonas and Comamonas in its degradation. The microbial communities appeared highly complex and diverse across both the sites and in the SEREBAR process. An increased population of naphthalene degraders was associated with naphthalene removal. CONCLUSION: The distribution of micro-organisms in general and naphthalene degraders across the site was highly heterogeneous. Comparisons made between areas contaminated with polycyclic aromatic hydrocarbons (PAH) and those not contaminated, revealed differences in the microbial community profile. The likelihood of noncultured bacteria being dominant in mediating naphthalene removal was evident. SIGNIFICANCE AND IMPACT OF THE STUDY: This work further emphasizes the importance of both traditional and molecular-based tools in determining the microbial ecology of contaminated sites and highlights the role of noncultured bacteria in the process.

The role of stable isotopes in human identification: a longitudinal study into the variability of isotopic signals in human hair and nails.

Recent natural catastrophes with large-scale loss of life have demonstrated the need for a new technique to provide information for disaster victim identification when DNA methods fail to yield the identification of an individual, or in other situations where authorities need to determine the recent geographical life history of people. The latter may be in relation to the identification of individuals detained on suspicion of terrorism or in relation to people-trafficking or smuggling. One proposed solution is the use of stable isotope profiling (SIP) using isotope ratio mass spectrometry (IRMS). Exploiting the link between the isotopic signal of dietary components and the isotopic composition of body tissue, the aim of this study was to refine a non-invasive method of analysing human material such as scalp hair and fingernails using SIP and to assess the degree of natural variability in these profiles. Scalp hair and fingernail samples were collected from British and non-British volunteers at Queen's University Belfast every 2 weeks for a minimum of 8 months. Samples were analysed using IRMS to determine their isotopic composition for 13C, 15N, 2H and 18O. The results of this longitudinal study yielded information on the natural variability of the isotopic composition of these tissues. The data demonstrate the relatively low degree of natural variation in the 13C/15N isotopic abundance of scalp hair and fingernails whilst greater variations were recorded in the hydrogen and oxygen values of the same samples. The 15N and 18O values of nail are noticeably more variable than that of scalp hair from the same subject. A hypothesis explaining this trend is put forward based on the faster rate of formation of hair than of nails. This means that there is less time for the compounds forming hair to be affected by biochemical processes that could alter their isotopic signature.

Stable isotope analysis of safety matches using isotope ratio mass spectrometry--a forensic case study.

Isotope ratio mass spectrometry (IRMS) was used to assess what contribution the technique could make towards the comparative analysis of matchstick samples within the 'normal' framework of a forensic investigation. A method was developed to allow the comparison of samples submitted as a result of an investigation, with the added advantage of rapid sample turn-around expected within this field. To the best of our knowledge this is the first time that wooden safety matches have been analysed using IRMS. In this particular case, bulk stable isotope analysis carrried out on a 'like-for-like' basis could demonstrate conclusively that matches seized from a suspect were different from those collected at the scene of crime. The maximum delta13C variability observed within one box was 2.5 per thousand, which, in conjunction with the error of measurement, was regarded to yield too wide an error margin as to permit differentiation of matchsticks based on 13C isotopic composition alone given that the 'natural' 13C abundance in wood ranges from -20 to -30 per thousand. However, from the delta2H values obtained for crime scene matches and seized matches of -114.5 per thousand and -65 per thousand, respectively, it was concluded that the matches seized were distinctly different from those collected at the crime scene.

13C-Isotope ratio mass spectrometry as a potential tool for the forensic analysis of white architectural paint: a preliminary study.

Paints have a dual role in society, to protect materials from environmental agents such as ultraviolet light, moisture and oxygen, and to make painted materials look more attractive. Variability in paint samples is often due to binder and pigment type within the sample. The most common resin used in decorative paints is drying oil alkyd resin, which incorporates soybean oil and vinyl acrylic based latexes. Traditional analytical methods used by forensic scientists may be able to say whether two paint samples are indistinguishable but cannot conclusively say that they both originate from the same source. To find out if isotopic composition can provide an added dimension of information, 28 different white architectural paints were analysed for (13)C abundance using isotope ratio mass spectrometry. In addition, variations in application, drying time and thickness were also investigated to assess the discriminatory power of (13)C data from white paints with an unknown history. Preliminary results indicate that this method could aid screening of paint samples.