A cheap and simple passive sampler using silicone rubber for the analysis of surface water by gas chromatography–time of flight mass spectrometry

Water pollution events may arise rapidly, requiring a methodology that is easy to implement, fast to deploy, and sufficiently sensitive to detect the trace presence of hazardous contaminants. A cheap and easy to use silicone rubber (polydimethylsiloxane (PDMS)) miniature passive sampler is described. In order to test the methodology, pollutants were concentrated, in situ, from surface water in and around Pretoria, South Africa. The versatile sampler allowed for conventional and enhanced sensitivity, solvent-free analysis by comprehensive gas chromatography – time of flight mass spectrometry (GCxGC-TOFMS) and high resolution TOFMS (GC-HRT). Contaminants detected in surface water include caffeine, personal care products, pharmaceuticals, pesticides and polycyclic aromatic hydrocarbons.Keywords: passive sampler, silicone rubber (PDMS) tubing, GCxGC-TOFMS, GC-HRT, surface water qualit

A cheap and simple passive sampler using silicone rubber for the analysis of surface water by gas chromatography–time of flight mass spectrometry

Water pollution events may arise rapidly, requiring a methodology that is easy to implement, fast to deploy, and sufficiently sensitive to detect the trace presence of hazardous contaminants. A cheap and easy to use silicone rubber (polydimethylsiloxane (PDMS)) miniature passive sampler is described. In order to test the methodology, pollutants were concentrated, in situ, from surface water in and around Pretoria, South Africa. The versatile sampler allowed for conventional and enhanced sensitivity, solvent-free analysis by comprehensive gas chromatography – time of flight mass spectrometry (GCxGC-TOFMS) and high resolution TOFMS (GC-HRT). Contaminants detected in surface water include caffeine, personal care products, pharmaceuticals, pesticides and polycyclic aromatic hydrocarbons.This paper was originally presented at the 2014 Water Institute of Southern Africa (WISA) Biennial Conference, Mbombela, 25–29 May 2014.National Research Foundation (NRF)http://www.wrc.org.zaam201

Establishing an alternative method for the quantitative analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by comprehensive two dimensional gas chromatography-time-of-flight mass spectrometry for developing countries

Comprehensive Gas Chromatography–Time-of-Flight Mass Spectrometry (GC×GC–TOFMS) methodology has been refined for the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in samples with different matrices. This is specifically for application in developing countries where access to gas chromatography–high resolution mass spectrometry (GC–HRMS) and highly skilled personnel is limited. The method, using an Rxi-5 Sil MS column in the first dimension (D) coupled with an Rtx-200 column in the second dimension (D), was used to quantify PCDDs and PCDFs in different environmental sample matrices. The results were compared with those obtained usingGC–HRMSand good agreement was observed. The limit of detection (LOD) for the method (300 fg on column for spiked soil samples) was determined using an Rxi-XLB (1D) column coupled with an Rtx-200 column (D). Preliminary South African sample results are also discussed. Isomer specificity for different tetrachloro dibenzo-p-dioxins (TCDDs) and tetrachloro dibenzofurans (TCDFs) was investigated using a commercial standard. Adequate resolution was achieved. The method as described has great attraction for developing countries being both financially and operationally favourable.http://www.elsevier.com/locate/chrom

Comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry for screening of organohalogenated compounds in cat hair

The coupling of comprehensive two-dimensional gas chromatography with high-resolution time-of-flight mass spectrometry offers the best separation efficiency combined with accurate mass measurements over a wide mass range. The tremendous power of this screening tool is illustrated by trace qualitative screening analysis of organohalogenated compounds (OHCs) in pet cat hair. Tentative identification was supported by mass spectral database searches and elemental formula prediction from the experimentally determined accurate mass data. This screening approach resulted in the first tentative identification of pentabromoethylbenzene, decabromodiphenyl ethane, hexabromocyclododecane, trisbromoneopentyl alcohol, tris(2-chloroethyl) phosphate and tris(2-chloroisopropyl)phosphate in the South African indoor environment. A total of seventy-two OHCs were identified in the samples and include known flame retardants, such as polybrominated diphenyl ethers, and legacy contaminants such as polychlorinated biphenyls and organochlorine, organophosphorous and pyrethroid pesticides. The results obtained from cat hair indicate that these pets are exposed to complex mixtures of OHCs and the detection of these compounds suggests that non-invasive cat hair samples can be used to model indoor exposure with reference to external deposition of OHCs present in the air and dust surrounding people. Toddlers share the same environment as pet cats and therefore also the same health risks

Mycotoxins and toxigenic fungi in sago starch from Papua New Guinea

Aims: to assay sago starch from Papua New Guinea (PNG) for important mycotoxins and to test fungal isolates from sago for mycotoxin production in culture.\ud \ud Methods and Results: sago starch collected from Western and East Sepik Provinces was assayed for aflatoxins, ochratoxin A, cyclopiazonic acid, sterigmatocystin, citrinin and zearalenone and all 51 samples were negative. Frequently\ud isolated species of Penicillium (13), Aspergillus (five) and Fusarium (one) were cultured on wheat grain, and tested for the production of ochratoxin A, cyclopiazonic acid, sterigmatocystin, citrinin, patulin and penicillic acid. All 12 isolates of P. citrinin and one of two A. flavipes isolates produced citrinin. A single isolate of A. versicolor produced sterigmatocystin. No other mycotoxins\ud were detected in these cultures.\ud \ud Conclusions: no evidence was found of systemic mycotoxin contamination of sago starch. However, the isolation of several mycotoxigenic fungi shows the potential for citrinin and other mycotoxins to be produced in sago stored\ud under special conditions.\ud \ud Significance and Impact of the study: sago starch is the staple carbohydrate in lowland PNG and the absence of mycotoxins in freshly prepared sago starch is a positive finding. However, the frequent isolation of citrinin-producing fungi indicates a potential health risk for sago consumers, and food safety is dependant on promoting good storage practices

Experience in South Africa of combining bioanalysis and instrumental analysis of PCDD/Fs

We outline the experiences and the challenges of optimizing two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOF-MS) in conjunction with the H4IIE-luc bioassay for analyzing polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in the South African context. Investigating such alternative analytical methods can assist countries with developing economies to meet their obligations under the Stockholm Convention.Water Research Commission (WRC) of South Africa (K5/1561) and the South African/Norwegian Bilateral Agreement administered by the National Research Foundations (NRF) of South Africa and the Research Council of Norway (UID 64489).The authors also acknowledge support from a Discovery Grant from the National Science and Engineering Research Council of Canada (Project # 326415-07) and an instrumentation grant from the Canada Foundation for Infrastructure. Prof. Giesy was supported by the program of 2012 "High Level Foreign Experts" (#GDW20123200120) funded by the State Administration of Foreign Experts Affairs,the P.R. China to Nanjing University and the Einstein Professor Program of the Chinese Academy of Sciences. He was also supported by the Canada Research Chair program, an at large Chair Professorship at the Department of Biology and Chemistry and State Key Laboratory in Marine Pollution, City University of Hong Kong.http://www.elsevier.com/locate/trachb201