Preserving Cultural Diversity in Rural Africa Using Renewable Energy.

Ninety percent of the large interior, rural part of Africa is not an abundant user of fossil fuels and is not connected to an electricity grid. This limits habitability and leads to significant migration to larger cities in attempts to improve economic and social welfare, which happens at the cost of its rich cultural diversity by inevitable adaption and mixing of societies. A direct transition from a firewood to an off-grid renewable electricity age can mitigate this detrimental development.

Advancing the analytical toolkit in the investigation of vector mosquito host biting site selection.

High-resolution mass spectrometry and ion mobility spectrometry provide additional confidence in biological marker discovery and elucidation by adding additional peak capacity through physiochemical separation orthogonal to chromatography. Sophisticated analytical techniques have proved valuable in the identification of human skin surface chemicals used by vector mosquitoes to find their human host. Polydimethylsiloxane (PDMS) was used as a non-invasive passive wearable sampler to concentrate skin surface non-volatile and semi-volatile compounds prior to solvent desorption directly in an LC vial, thereby simplifying the link between extraction and analysis.

Detection of tuberculosis-associated compounds from human skin by GCxGC-TOFMS.

Tuberculosis (TB) remains a global health concern. This study aimed to investigate the potential of human skin volatile organic compounds (VOCs) as prospective biomarkers for TB diagnosis. It employed a non-invasive approach using a wearable silicone rubber band for VOC sampling, comprehensive gas chromatography - time of flight mass spectrometry (GCxGC-TOFMS), and chemometric techniques.

The Sex Pheromone of the Pine Brown-Tail Moth, Euproctis terminalis (Lepidoptera: Erebidae).

The pine brown tail moth, Euproctis terminalis (Walker 1855), is a periodic pest in pine plantations in South Africa. The larvae feed on pine needles and can cause severe defoliation when population densities are high. Population densities fluctuate temporally and spatially, complicating the prediction of potential growth loss and tree mortality.

Mass spectral studies on the human skin surface for mosquito vector control applications.

Human skin surface chemical cues comprise a complex mixture of compounds that mosquitoes use to locate and select their human host, based on inter- and intra-human variation in chemical profiles. The complexity of the skin surface matrix calls for advanced analytical techniques to enable separation and identification of biomarkers, which may be used as topical attractants and repellants in future mosquito vector control programmes. The perceived mosquito attractiveness between 20 volunteers and the preference of mosquitoes to bite certain regions, namely, ankle versus wrist, of the human host were investigated in this study, by comparing skin surface chemical profiles.

Non-invasive sorptive extraction for the separation of human skin surface chemicals using comprehensive gas chromatography coupled to time-of-flight mass spectrometry: A mosquito-host biting site investigation.

Variation in inter-human attractiveness to mosquitoes, and the preference of mosquitoes to bite certain regions on the human host, are possible avenues for identifying lead compounds as potential mosquito attractants or repellents. We report a practical, non-invasive method for the separation and detection of skin surface chemical compounds and comparison of skin chemical profiles between the ankle and wrist skin surface area sampled over a 5-day period of a human volunteer using comprehensive gas chromatography coupled to time-of-flight mass spectrometry. An in-house made polydimethylsiloxane passive mini-sampler, worn as an anklet or a bracelet, was used to concentrate skin volatiles and semi-volatiles prior to thermal desorption directly in the gas chromatography.

Chemical profiling of the human skin surface for malaria vector control via a non-invasive sorptive sampler with GC×GC-TOFMS.

Volatile organic compounds (VOCs) and semi-VOCs detected on the human skin surface are of great interest to researchers in the fields of metabolomics, diagnostics, and skin microbiota and in the study of anthropophilic vector mosquitoes. Mosquitoes use chemical cues to find their host, and humans can be ranked for attractiveness to mosquitoes based on their skin chemical profile. Additionally, mosquitoes show a preference to bite certain regions on the human host.

Short-, medium-, and long-chain chlorinated paraffins in South African indoor dust and cat hair.

Polychlorinated n-alkanes or chlorinated paraffins (CPs) contain a magnitude of structural isomers and are categorized as short-chain (SCCPs), medium-chain (MCCPs), and long-chain (LCCPs) CPs, according to the carbon chain lengths. In this study the ƩSCCPs, ƩMCCPs, and ƩLCCP concentrations are reported for South African indoor dust and pet cat hair. The median concentrations of the ƩCPs (C-C) ranged from 33 to 663 μg/g for freshly collected dust (FD), 36-488 μg/g for dust collected from household vacuum cleaner bags (VD), and 1.

Brominated and organophosphorus flame retardants in South African indoor dust and cat hair.

Flame retardants (FRs), such as brominated flame retardants (BFRs) and organophosphorus flame retardants (OPFRs), are diverse groups of compounds used in various products related to the indoor environment. In this study concentrations of eight polybrominated diphenyl ethers (PBDEs), two alternative BFRs and ten OPFRs were determined in indoor dust (n = 20) and pet cat hair (n = 11) from South Africa. The OPFRs were the major FRs, contributing to more than 97% of the total FR concentration.

Development and optimization of a plunger assisted solvent extraction method for polycyclic aromatic hydrocarbons sampled onto multi-channel silicone rubber traps.

A plunger assisted solvent extraction (PASE) method for multi-channel silicone rubber trap samplers was developed and evaluated as an alternative to direct thermal desorption for the monitoring of polycyclic aromatic hydrocarbons (PAHs). The proposed extraction method was simple, fast (a total of 2 min for extraction), and used a small volume of solvent (a total of 2 mL from two sequential 1 mL extractions). The PASE method presented an advantage over thermal desorption in that samples could be re-analyzed, as only a portion of the extract was injected.

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.

Comparison of a disposable sorptive sampler with thermal desorption in a gas chromatographic inlet, or in a dedicated thermal desorber, to conventional stir bar sorptive extraction-thermal desorption for the determination of micropollutants in water.

The presence of micropollutants in the aquatic environment is a worldwide environmental concern. The diversity of micropollutants and the low concentration levels at which they may occur in the aquatic environment have greatly complicated the analysis and detection of these chemicals. Two sorptive extraction samplers and two thermal desorption methods for the detection of micropollutants in water were compared.

Preliminary screening of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA) flame retardants in landfill leachate.

The occurrence of selected brominated flame retardants, including nine polybrominated diphenyl ether (PBDE) congeners, hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA) in leachate samples from eight landfill sites in South Africa, were investigated. In addition, the possible influences of dissolved organic carbon on their levels were also evaluated. Filtered leachate samples were subjected to solid-phase extraction to isolate the various target compounds.

Database-driven screening of South African surface water and the targeted detection of pharmaceuticals using liquid chromatography - High resolution mass spectrometry.

Pharmaceuticals and personal care products are released into aquatic environments, largely as a result of ineffectual removal during wastewater treatment. Here we present a screening strategy based on the use of three commercially available mass spectral databases, combined into a single searchable entity and parallelized by cluster computing. In addition to this, a targeted solid phase extraction method with Ultra High Pressure Liquid Chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC-QTOF) was used to quantify 99 pharmaceuticals in South African surface water on a national level.

Optimization of Pheromone Traps for Coryphodema tristis (Lepidoptera: Cossidae).

The Coryphodema tristis (Drury) is an important pest of Eucalyptus nitens (Deane and Maiden) plantations in South Africa. The gregarious larvae of this pest cause damage by feeding on the tree sapwood, and adults emerge in spring each year. The aim of this study was to optimize pheromone traps for operational use in management programs.

Multi-channel silicone rubber traps as denuders for gas-particle partitioning of aerosols from semi-volatile organic compounds.

During many measurements it is important to account for possible changes in the gas-particle distribution of aerosols containing semi-volatile organic compounds (SVOCs). If denuders are combined with currently used personal air samplers, a simultaneous differential sampling of the gas and particle phase is possible. Here we analysed the transmission efficiency of denuders based on multi-channel silicone rubber traps (setup: 9 cm long glass liner (ID 4 mm), containing 22 parallel silicone rubber tubes (55 mm long, ID 0.

Determination of endocrine disrupting chemicals and antiretroviral compounds in surface water: A disposable sorptive sampler with comprehensive gas chromatography - Time-of-flight mass spectrometry and large volume injection with ultra-high performance liquid chromatography-tandem mass spectrometry.

Many rural dwellers and inhabitants of informal settlements in South Africa are without access to treated water and collect untreated water from rivers and dams for personal use. Endocrine disrupting chemicals (EDCs) have been detected in surface water and wildlife of South Africa. EDCs are often present in complex environmental matrices at ultra-trace levels complicating detection thereof.

Critical review of the analysis of brominated flame retardants and their environmental levels in Africa.

World-wide, the prevalence of brominated flame retardants (BFRs) is well documented for routine analysis of environmental and biological matrices. There is, however, limited information on these compounds in the African environment and insufficient information on the analytical approaches used to obtain data. This paper presents a review on BFR levels in the African environment and the various analytical methodologies specifically applied in Africa for polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls and alternative-BFRs.

The chlorination behaviour and environmental fate of the antiretroviral drug nevirapine in South African surface water.

The wastewater treatment process, besides discharging pharmaceuticals into the environment, has been found to result in the formation of a variety of undescribed compounds. Here we investigate the laboratory scale chlorination of the commonly used anti-HIV drug Nevirapine, characterise its disinfection transformation products (DTPs), and using liquid chromatography with high resolution mass spectrometry, screen environmental surface water for these DTPs. Chlorination of Nevirapine was scaled up, fractioned by preparative chromatography and the fractions were tested in vitro for toxicity and anti-HIV activity.

Identification of the sex pheromone of the tree infesting Cossid Moth Coryphodema tristis (Lepidoptera: Cossidae).

The cossid moth (Coryphodema tristis) has a broad range of native tree hosts in South Africa. The moth recently moved into non-native Eucalyptus plantations in South Africa, on which it now causes significant damage. Here we investigate the chemicals involved in pheromone communication between the sexes of this moth in order to better understand its ecology, and with a view to potentially develop management tools for it.

Polybrominated diphenyl ethers (PBDEs) in eggshells of the Southern Ground-Hornbill (Bucorvus leadbeateri) and Wattled Crane (Bugeranus carunculatus) in South Africa.

This study was undertaken to assess the levels of eight PBDE congeners, namely: PBDE-17, 47, 100, 99, 154, 153, 183 and 209 in eggshells of Southern Ground-Hornbill (SGH) Bucorvus leadbeateri and Wattled Crane (WC) Bugeranus carunculatus obtained from different nesting sites within the eastern savanna of Limpopo Province and the midlands of KwaZulu-Natal, respectively. Analyses were performed using gas chromatography–mass spectrometry employing the electron impact ionization technique. The results obtained indicated that the lower brominated congeners were predominant in both species.

Investigating the coffee flavour in South African Pinotage wine using novel offline olfactometry and comprehensive gas chromatography with time of flight mass spectrometry.

Pinotage wine from several South African wine cellars has been produced with a novel coffee flavour. We have investigated this innovative coffee effect using in house developed solventless sampling and fractionating olfactometric techniques, which are unique in their ability to study synergistic aroma effects as opposed to traditional gas chromatography olfactometry (GC-O) which is designed to, ideally, evaluate single eluting compounds in a chromatographic sequence. Sections of the chromatogram, multiple or single peaks, were recaptured on multichannel open tubular silicone rubber (polydimethylsiloxane (PDMS)) traps at the end of a GC column.

Two multidimensional chromatographic methods for enantiomeric analysis of o,p'-DDT and o,p'-DDD in contaminated soil and air in a malaria area of South Africa.

In rural parts of South Africa the organochlorine insecticide DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is still used for malaria vector control where traditional dwellings are sprayed on the inside with small quantities of technical DDT. Since o,p'-DDT may show enantioselective oestrogenicity and biodegradability, it is important to analyse enantiomers of o,p'-DDT and its chiral degradation product, o,p'-DDD, for both health and environmental-forensic considerations. Generally, chiral analysis is performed using heart-cut multidimensional gas chromatography (MDGC) and, more recently, comprehensive two-dimensional gas chromatography (GC×GC).

Novel method for determining DDT in vapour and particulate phases within contaminated indoor air in a malaria area of South Africa.

The organochlorine insecticide DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) is still used for malaria vector control in certain areas of South Africa. The strict Stockholm Convention on Persistent Organic Pollutants (POPs) allows spraying on the inside of traditional dwellings with DDT. In rural villages contaminated dust presents an additional pathway for exposure to DDT.

The use of multi-channel silicone rubber traps as denuders for polycyclic aromatic hydrocarbons.

Atmospheric polycyclic aromatic hydrocarbons are ubiquitous environmental pollutants, which may be present both in the gaseous phase and adsorbed onto the surface of particles. Denuders are sampling devices which have been effectively employed in such partitioning applications. Here we describe and characterise a novel miniature denuder consisting of two multi-channel silicone rubber traps (each 178 mm long, 6 mm o.