How well do our measurements measure up? An overview of South Africa’s first proficiency testing scheme for organochlorine pesticides in water

Access to safe drinking water is a basic human right in South Africa. Therefore, the accurate measurement of water quality is critical in ensuring the safety of water prior to its intended use. Proficiency testing schemes (PTSs) are a recognised form of assessing the technical competence of laboratories performing these analyses. There are over 200 water testing laboratories in South Africa, with only 51 being accredited for testing some or all parameters (physical, chemical and microbiological content) prescribed in SANS 241. Only a limited number of laboratories test for organic contaminants, as this requires advanced, costly analytical instrumentation, such as GC-FID/ECD/MS and LC-UV/MS, as well as skilled staff. These laboratories are either looking at selected organic contaminants listed in the World Health Organisation (WHO) drinking water guidelines or performing the minimum requirements, as stipulated in SANS 241, for phenols, atrazine, trihalomethanes and total dissolved organic content. Whereas several local PTS providers are addressing the competent assessment of microbiological, physical and inorganic chemical testing of water, a clear need for a South African PTS provider for organic contaminant analysis in water was identified by NMISA (National Metrology Institute of South Africa) in 2012. The key drivers for the coordination of a local PTS stem mainly from the limited stability of analytes in the samples for analysis and the high cost and logistics of international PTS participation. During 2012 and 2013, NMISA conducted a PTS trial round, a workshop and 2 additional PTS rounds for organochlorine pesticides in water, for South African laboratories, and also several international participants from other countries in Africa. This paper will highlight some of the challenges faced by laboratories when analysing organochlorine pesticides at the ng/ℓ concentration level. Issues surrounding the comparability of measurement results, traceability, method validation and measurement uncertainty are also discussed.Keywords: Proficiency testing schemes, PTS, organochlorine pesticides, drinking wate

Pesticide Use in South Africa: One of the Largest Importers of Pesticides in Africa

South Africa is a diverse country, with a diverse environment that is home to more than 49 000 000 people. Pesticide usage is very often necessary to maintain both agricultural productivity as well as human health. The climatic conditions range from semi-tropic to semi-arid regions. Although the majority of the country has summer rainfall, the south western coastal region is predominantly a winter rainfall area. These variations in climate allows for a wide variety of crops, from tropical fruit to maize and tree plantations. Each individual crop is susceptible to a unique host of pests that in-turn require a unique mixture of pesticides to ensure the best resulting turnover. Currently, South Africa has more than 500 registered pesticides (Pesticide Action Network (PAN), 2010) and is one of the four largest importers of pesticides in sub-Saharan Africa (Osbanjo et al., 2002). In 2006 the import of insecticides, fungicides and herbicides that were packaged for retail totalled $ 170 056 000 the main import partners being Australia, China, Germany and the United States of America (USA) (International Trade Centre, 2011). These pesticides are used in almost every facet of our everyday lives; ensuring the quantity and quality of food we eat to managing the number of rodents and insects in our homes. Although it is evident that there is a vast amount of pesticides present in the South African environment, there is very limited data on the production of pesticides. The last published data indicates that in 2002 around 10 000 kℓ of liquid insecticides was produced exclusively for crop protection of which 43% consisted of organophosphates. During the same year 2 800-tonnes of solid insecticides were produced (Statistics South Africa, 2003). Although the usefulness of pesticides cannot be denied, the negative environmental and human health effects cannot be ignored. In South Africa, a number of environmental and anthropogenic factors have to be considered before the impact of large-scale pesticide use can be assessed. South Africa is a water poor country, with water resources being utilised to their maximum capacity. As discussed by Dabrowski et al. (2009), the trade-off between the economic benefits of exporting agricultural products has to be measured against the loss of water, not only through crop irrigation but also through water quality degradation. The article highlighted this aspect through the calculation of virtual water volumes. These calculated volumes indicated that to ensure sufficient dilution of all agrochemicals, to an acceptable water quality level (used in a typical farming situation applying current-use pesticides), was greater than the amount of water needed for irrigation. The seriousness of these scenarios is highlighted in literature where a diverse array of agricultural chemicals has been measured during run-off events, by once-off sampling and by water monitoring during the growing seasons. Detectable levels of atrazine, terbuthylazine, simazine, acetochlor (Du Preez et al., 2005), DDT and its metabolites, endosulfan, hexachlorocyclohexane (HCH), heptachlor, aldrin, dieldrin, endrin, chlordane (Fatoki et al., 2003), azinophos-methyl, chloropyriphos (Schultz et al., 2001; Dabrowski et al., 2002) prothiofos (Schultz, 2001), malathion, zendoxsulfan (Thiere &  Schultz, 2004), cypermethrin and fenvalerate (Bollmohr et al., 2007), to name a few, have all been measured in South African waters. Pesticides in the aquatic environment have the potential to affect all end-users, including both humans and wildlife. South Africa has the distinction of being one of the countries with the most species richness in the world. To date more than 900 bird species as well as over 200 mammals, call South Africa home. Of these mammals, seven species are endangered and 30 are vulnerable according to the 2004 IUCN red data list (IUCN, 2010). These endangered species include bats, moles, shrews and mice that are often insectivorous, thus increasing their risk of unintentional exposure to pesticides. Within avian populations, 11 species are listed as critically endangered and 43 species as vulnerable. The sensitivity of avian species to pollutants has been widely reported. With this unique diversity of species, South Africans have a responsibility towards maintaining the viability of ecosystems and natural habitats to ensure the continued existence of these creatures. This objective is not only morally relevant but also economically relevant especially in a country where tourism creates over 400 000 jobs and contributes approximately 8% to the GDP. Few studies have reported the levels of insecticides in wildlife species. However, pesticides have been detected in wild bird species (Van Wyk et al., 2001; Bouwman et al., 2008), as well as in indigenous fish species (Barnhoorn et al., 2009), indicating pesticide contamination within various habitats. This is of particular concern due to the health risks associated with many pesticides

Сотрудничество в области производства стандартных образцов, финансируемого государством

Emteborg H. et al. Cooperation in publicly funded reference material production. Accred Qual Assur. 2018;23(6):371-377. DOI.org/10.1007/s00769-018-1349-1. Первоисточник статьи: Accred Qual Assur (2018) 23:371. https://doi.org/10.1007/s00769-018-1349-

Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

On-line derivatization for resonance-enhanced multiphoton ionization time-of-flight mass spectrometry

On-line derivatization for resonance-enhanced multiphoton ionization time-of-flight mass spectrometry : detection of aliphatic aldehydes and amines via reactive coupling of aromatic photo ionization labels / R. Zimmermann ...- In: Analytical chemistry. 77. 2005. S. 1-1

On-line derivatization for resonance-enhanced multiphoton ionization time-of-flight mass spectrometry:Detection of aliphatic aldehydes and amines via reactive coupling of aromatic photo ionization labels.

Resonance-enhanced multiphoton ionization time-of-flight mass spectrometry (REMPI-TOFMS) is a powerful technique for the on-line analysis of aromatic compounds with unique features regarding selectivity and sensitivity. Aliphatic compounds, however, are difficult to address by REMPI due to their unfavorable photo ionization properties. This paper describes the proof of concept for an on-line derivatization approach for converting nonaromatic target analytes into specific, photoionizable aromatic derivatives that are readily detectable by REMPI-TOFMS. A multichannel silicone trap or poly(dimethylsiloxane) (PDMS) open tubular capillary was used as a reaction medium for the derivatization of volatile alkyl aldehydes and alkylamines with aromatic "photoionization labels"and to concentrate the resulting aromatic derivatives. The aldehydes formaldehyde, acetaldehyde, acrolein, and crotonal, which when underivatized are poorly detectable by REMPI, were converted into their easily photoionizable phenylhydrazone derivatives by the on-line reaction with phenylhydrazine as reagent. Similarly, the methyl-, ethyl-, propyl-, and butylamines were converted into their REMPI-ionizable benzaldehyde alkylimine derivatives by the on-line reaction with benzaldehyde as reagent. The derivatives were thermally desorbed from the PDMS matrix and transferred into the REMPI-TOFMS for detection. The REMPI-TOFMS detection limits obtained for acetaldehyde; acrolein; crotonal; and methyl-, ethyl-, propyl-, and butylamine using this photo ionization labeling method were in the sub-parts-per-million range and, thus, readily below the permissible exposure limits set by OSHA

Os cuidados imediatos prestados ao recém-nascido e a promoção do vínculo mãe-bebê Los cuidados inmediatos prestados a los recién nacidos y la promoción del vínculo madre-bebé Immediate care given to newborns and promotion of mother-baby bond

Trata-se de um estudo descritivo em abordagem qualitativa, com objetivo de compreender como o momento do parto foi percebido pelas mães e de que maneira as ações dos profissionais contribuíram para facilitar sua aproximação ao recém-nascido. Foram entrevistadas 25 multíparas, de uma maternidade pública no Rio de Janeiro, que tiveram recém-nascidos de baixo risco e parto normal. A análise de conteúdo dos relatos revelou que os cuidados imediatos prestados ao bebê, distante do olhar materno, geram nas mães preocupação, sensação de afastamento e medo da separação do bebê. Algumas mulheres, todavia, valorizaram a assistência intervencionista por acreditar que estes cuidados são indispensáveis para garantir a integridade física de seus filhos. Podemos concluir que, embora valorizem a aproximação a seus bebês no pós-parto imediato, as mães investigadas não conseguem perceber a interferência desse contato inicial no estabelecimento do vínculo precoce em decorrência de inúmeros fatores, dentre eles, os socioculturais.<br>Se trata de un estudio descriptivo en abordaje cualitativa, con objetivo de comprender como el momento del parto fue percibido por las madres y de que manera las acciones de los profesionales contribuyeron para facilitar su aproximación al recién-nacido. Fueron entrevistadas 25 multíparas, de una maternidad pública en Rio de Janeiro, que tuvieron recién-nacidos de bajo riesgo y parto normal. La análisis del contenido de los relatos rebeló que los cuidados inmediatos prestados al bebé, distante de la mirada materna, generan en las madres preocupación, sensación de alejamiento y miedo de la separación del bebé. Algunas mujeres, todavía, valorizaron la asistencia intervencionista por creer que estos cuidados son indispensables para garantizar la integridad física de sus hijos. Podemos concluir que, mismo que valoricen la aproximación a sus bebés en el pos-parto inmediato, las madres investigadas no consiguen percibir la interferencia de ese contacto inicial en el establecimiento del vínculo precoz en descorrimiento de innúmeros factores, entre ellos, los socioculturales.<br>This is a descriptive study with a qualitative approach aimed at understanding how mothers perceived the moment of childbirth and how the actions of the professionals contributed to facilitate their closeness to their babies. Twenty-five multiparous women in a public maternity in Rio de Janeiro who had had low risk, normal labor deliveries were interviewed. The analysis of the reports revealed that immediate care given to babies away from their mother's view generates in mothers concern, a feeling of distance and fear of being separated from the baby. However, some women valued the interventionist assistance because they believe that this care is indispensable to ensure their child's physical integrity. Although they valued closeness to their babies in the immediate post-labor period, the surveyed mothers failed to notice the interference of this initial contact for the establishment of an early bond because of a number of factors, among them social-cultural ones