Taking control of microplastics data: A comparison of control and blank data correction methods

Although significant headway has been achieved regarding method harmonisation for the analysis of microplastics, analysis and interpretation of control data has largely been overlooked. There is currently no consensus on the best method to utilise data generated from controls, and consequently many methods are arbitrarily employed. This study identified 6 commonly implemented strategies: a) No correction; b) Subtraction; c) Mean Subtraction; d) Spectral Similarity; e) Limits of detection/ limits of quantification (LOD/LOQ) or f) Statistical analysis, of which many variations are possible. Here, the 6 core methods and 45 variant methods (n = 51) thereof were used to correct a dummy dataset using control data. Most of the methods tested were too inflexible to account for the inherent variation present in microplastic data. Only 7 of the 51 methods tested (six LOD/LOQ methods and one statistical method) showed promise, removing between 96.3 % and 100 % of the contamination data from the dummy set. The remaining 44 methods resulted in deficient corrections for background contamination due to the heterogeneity of microplastics. These methods should be avoided in the future to avoid skewed results, especially in low abundance samples. Overall, LOD/LOQ methods or statistical analysis comparing means are recommended for future use in microplastic studies

Ingestion and depuration of microplastics by a planktivorous coral reef fish, Pomacentrus amboinensis

Microplastics are ubiquitous contaminants in marine environments and organisms. Concerns about potential impacts on marine organisms are usually associated with uptake of microplastics, especially via ingestion. This study used environmentally relevant exposure conditions to investigate microplastic ingestion and depuration kinetics of the planktivorous damselfish, Pomacentrus amboinensis. Irregular shaped blue polypropylene (PP) particles (longest length 125–250 μm), and regular shaped blue polyester (PET) fibers (length 600–700 μm) were selected based on physical and chemical characteristics of microplastics commonly reported in the marine environment, including in coral reef ecosystems. Individual adult damselfish were exposed to a single dose of PP particles and PET fibers at concentrations reported for waters of the Great Barrier Reef (i.e., environmentally relevant concentrations, ERC), or future projected higher concentrations (10x ERC, 100x ERC). Measured microplastic concentrations were similar to their nominal values, confirming that PP particles and PET fibers were present at the desired concentrations and available for ingestion by individual damselfish. Throughout the 128-h depuration period, the 88 experimental fish were sampled 2, 4, 8, 16, 32, 64, and 128-h post microplastic exposure and their gastrointestinal tracts (GIT) analyzed for ingested microplastics. While damselfish ingested both experimental microplastics at all concentrations, body burden, and depuration rates of PET fibers were significantly larger and longer, respectively, compared to PP particles. For both microplastic types, exposure to higher concentrations led to an increase in body burden and lower depuration rates. These findings confirm ingestion of PP particles and PET fibers by P. amboinensis and demonstrate for the first time the influence of microplastic characteristics and concentrations on body burden and depuration rates. Finally, despite measures put in place to prevent contamination, extraneous microplastics were recovered from experimental fish, highlighting the challenge to completely eliminate contamination in microplastic exposure studies. These results are critical to inform and continuously improve protocols for future microplastics research, and to elucidate patterns of microplastic contamination and associated risks in marine organisms

Adsorption Of A Copper (ii) Complex On Calcium Phosphate Intercalated With 4-aminobenzoic Acid -synthesis And Electrochemical Investigation

In this study, the adsorption isotherm of copper (II) on a calcium phosphate host intercalated with 4-aminobenzoic acid in an ethanol solution was investigated. This gave a maximum adsorption capacity of 1.74 mmol g -1. The material was incorporated into a carbon-paste electrode, and its electrochemical properties were investigated. However, for a dopamine solution, the anodic peak current increased owing to the electrocatalytic oxidation. The electrode presented the same response for at least 150 successive measurements, showing good repeatability. The modified electrode is very stable and reproducible. The electrode sensor was successfully applied for dopamine determination in pharmaceutical preparations.36811701175Song, S., Clark, R.A., Bowden, E.F., Taylor, M.J., (1993) J. Phys. Chem., 97, p. 6564Edmonds, T., (1988) Chemical Sensors, , Blackie: GlasgowYabuki, S., Mizutani, F., Asai, M., (1991) Biosens. Bioelectron., 6, p. 311Gorton, L., Torstensson, A., Jaegfeld, H., Johansson, G., (1984) J. Electroanal. Chem., 161, p. 103Castellani, A.M., Gushikem, Y., (2000) J. Colloid Interface Sci., 230, p. 195Zaitseva, G., Gushikem, Y., Ribeiro, E.S., Rosatto, S.S., (2002) Electrochim. Acta, 47, p. 1469Borgo, C.A., Lazarin, A.M., Gushikem, Y., (2002) Sens. Actuators, B, 87, p. 498Kalcher, K., Kauffmann, J.M., Wang, J., Svancara, I., Vytras, K., Neuhold, C., Yang, Z., (1995) Electroanalysis, 7, p. 5Gorton, L., (1995) Electroanalysis, 7, p. 23Dias, S.L.P., Gushikem, Y., Ribeiro, E.S., Benvenutti, E.V., (2002) J. Electroanal. Chem., 523, p. 64Lazarin, A.M., Airoldi, C., (2004) Anal. Chim. Acta, 523, p. 89Karimi-Maleh, H., Ensafi, A.A., Ensafi, H.R., (2009) J. Braz. Chem. Soc., 20, p. 880Raoof, J., Ojani, R., Chek In, F., Hosseinzadeh, R., (2007) Int. J. Electrochem. Sci., 2, p. 848Liu, S., Ju, H., (2003) Biosens. Bioelectron., 19, p. 177Hrbác, J., Gregor, C., Machová, M., Králová, J., Bystron, T., Cíz, M., Louk, A., (2007) Bioelectrochemistry, 71, p. 46Milanese, C., Buscaglia, V., Maglia, F., Anselmi-Tamburini, U., (2002) J. Phys. Chem. B, 106, p. 5859Evtugyn, G.A., Stoikov, I.I., Beljyakova, S.V., Shamagsumova, R.V., Stoikova, E.E., Yu., A., Zhukov A., Yu., Budnikov, H.C., (2007) Talanta, 71, p. 1720Ensafi, A.A., Mirmomtaz, E., (2006) J. Electroanal. Chem., 583, p. 176Wang, J., (2005) Electroanalysis, 17, p. 7Welch, C.M., Compton, R.G., (2006) Anal. Bioanal. Chem., 384, p. 601Zeng, H., Jiang, Y., Xie, G., Yu, J., (2007) Sens. Actuators, B, 122, p. 1Lee, S., Lee, Y., Sawada, K., Takao, H., Ishida, M., (2008) Biosens. Bioelectron., 24, p. 410Clearfield, A., (1988) Chem. Rev., 88, p. 125Ruan, C., Yang, F., Xu, J., Lei, C., Deng, J., (1997) Electroanalysis, 15, p. 11804Ramesh, P., Suresh, G.S., Sampath, S., (2004) J. Electroanal. Chem., 561, p. 173Shankaran, D.R., Kimura, K., Kato, T., (2003) Sens. Actuators, B, 94, p. 73Wu, K., Fei, J., Hu, S., (2003) Anal. Biochem., 318, p. 100Reis, A.P., Tarley, C.R.T., Maniasso, N., Kubota, L.T., (2005) Talanta, 67, p. 829Poojary, D.M., Zhang, B., Cabeza, A., Aranda, M.A.G., Bruque, S., Clearfield, A., (1996) J. Mater. Chem., 6, p. 639Silva, C.F.N., Lazarin, A.M., Sernaglia, L.R.L., Andreotti, E.I.S., (2012) Mater. Res. Bull., 47, p. 1539Lazarin, A.M., Ganzerli, T.A., Sernaglia, R.L., Andreotti, E.I.S., Airoldi, C., (2009) Mater. Res. Bull., 44, p. 2087Kim, H.-N., Keller, S.W., Mallouk, T.E., Schmitt, J., (1997) Chem. Mater., 9, p. 1414Airoldi, C., Lima, C.B.A., (2004) Solid State Sci, 6, p. 1245Pessôa, C.A., Gushikem, Y., Kubota, L.T., (1997) Electroanalysis, 10, p. 800Zaitsev, V.N., Skopenko, V.V., Trofimchuk, A.K., (1984) Russ. J. Inorg. Chem., 29, p. 700Lazarin, A.M., Borgo, C.A., Gushikem, Y., (2003) J. Membr. Sci., 221, p. 175Romanowshi, S.M.D., Mangrich, A.S., (2001) Quim. Nova, 5, p. 592Zurita, D., Scheer, C., Pierre, J.L., Saint-Aman, E., (1996) J. Chem. Soc. Dalton Trans., p. 4331Matovic, Z.D., Miletec, V.D., Samardzic, G., Pelosi, E., Lanelli, S., Trifunovic, S., (2005) Inorg. Chim. Acta, 358, p. 3135Muresan, V., Sbirna, L.S., Sbirna, S., Lepadatu, C.I., Muresan, N., (2001) Acta. Chim. Slov., 48, p. 439Borgo, C.A., Ferrari, R.T., Colpini, L.M.S., Costa, C.M.M., Baesso, M.L., Bento, A.C., (1999) Anal. Chim. Acta, 385, p. 103Gushikem, Y., Rosatto, S.S., (2001) J. Braz. Chem. Soc., 12, p. 695Zaldivar, G.A.P., Gushikem, Y., (1992) J. Electroanal. Chem., 337, p. 165Kubota, L.T., Gushikem, Y., (1993) J. Electroanal. Chem., 362, p. 219Ju, H., Gong, Y., Zhu, H., (2001) Anal. Sci., 17, p. 59Coutinho, C.F.B., Coutinho, L.F.M., Mazo, L.H., (2009) Quim. Nova, 32, p. 228Wen, X.-L., Jia, Y.-H., Liu, Z.-L., (1999) Talanta, 50, p. 1027Zheng, J., Zhou, X., (2007) Bioelectrochemistry, 70, p. 408Gilbert, O., Chandra, U., Swamy, B.E.K., Char, M.P., Nagaraj, C., Sherigara, B.S., (2008) Int. J. Electrochem. Sci., 3, p. 1186Pandurangachar, M., Swamy, B.E.K., Chandrashekar, B.N., Sherigara, B.S., (2009) Int. J. Electrochem. Sci., 4, p. 1319Ke, N.J., Lu, S.-S., Cheng, S.-S., (2006) Electrochem. Commun., 8, p. 1514Yi, S., Chang, H., Cho, H., Park, Y.C., Lee, S.H., Bae, Z., (2007) J. Electroanal. Chem., 602, p. 217Kim, Y.-R., Bong, S., Kong, Y.-J., Yan, Y., Marajan, R.K., Seung, K., Kim, H., (2010) Biosens. Bioelectron., 25, p. 2366Gelbert, M.B., Curran, D.J., (1986) Anal. Chem., 58, p. 102

Resistência a Septoria lycopersici em espécies de Solanum (Secção Lycopersicon) e em progênies de S. lycopersicum × S. peruvianum

Septoria leaf spot (Septoria lycopersici) is one of the major fungal diseases of tomatoes (Solanum lycopersicum) in tropical and subtropical regions with humid climates and/or in areas cultivated under sprinkler irrigation systems. Sources of resistance have been found in accessions of Solanum (section Lycopersicon) species. However, many of the described sources are not effective under Brazilian conditions. The objective of this work was to evaluate wild and cultivated Solanum (section Lycopersicon) germplasm to S. lycopersici isolates. A collection of 124 accessions was initially evaluated under greenhouse conditions. Ten accessions were highly resistance (HR), whereas 33 were classified as having a resistant (R) response to S. lycopersici isolates. Field evaluation was also conducted with a sub-set of accessions identified as either HR or R in the greenhouse experiment. This field evaluation confirmed greenhouse tests and indicated the presence of some potential sources of rate-reducing resistance. One highly resistant and eight resistant S. habrochaites accessions were identified as being resistant under both conditions, confirming that this wild species is one of the most promising sources of resistance to S. lycopersici. Five new sources with high levels of resistance were found in S. peruvianum accessions (PI-306811, CNPH-1036, LA-1910, LA-1984 and LA-2744). One accession derived from an interspecific cross between S. lycopersicum and S. peruvianum was also found to be highly resistant and might be useful to introgress resistance factors from this wild species into cultivated tomato germplasm. However, additional breeding efforts will be necessary to introgress into the cultivated tomato the resistance factors identified in other S. peruvianum accessions due to the presence of natural crossing barriers between the two species.A mancha-de-septória (Septoria lycopersici) é importante doença fúngica do tomateiro (Solanum lycopersicum) em áreas tropicais e subtropicais com alta umidade ou quando esta hortaliça é cultivada sob irrigação por aspersão. Fontes de resistência têm sido encontradas em germoplasma de Solanum (secção Lycopersicon). No entanto, muitas das fontes descritas não funcionam nas condições brasileiras. Avaliou-se uma coleção de germoplasma de tomate cultivado e selvagem (Solanum secção Lycopersicon) visando identificar novas fontes de elevada resistência. Uma coleção de 124 acessos foi inicialmente avaliada sob condições de casa de vegetação. Somente dez acessos foram classificados como altamente resistentes e 33 foram classificados como resistentes. Um ensaio de campo foi também conduzido com um subconjunto de acessos promissores identificados no primeiro experimento. Foi confirmada a resposta da maioria dos acessos avaliados em casa de vegetação e indicou a presença de fontes de resistência capazes de reduzir a taxa de progresso da doença. Um acesso de S. habrochaites com elevada resistência e oito acessos resistentes foram identificados, confirmando que esta espécie representa uma das mais promissoras fontes de genes de resistência a S. lycopersici. Cinco novas fontes com elevados níveis de resistência foram identificadas em acessos da espécie S. peruvianum (PI-306811, CNPH-1036, LA-1910, LA-1984 e LA-2744). Um acesso, derivado de cruzamento interespecífico entre S. lycopersicum e S. peruvianum também mostrou-se altamente resistente e poderá ser útil na introgressão deste(s) gene(s) em germoplasma de tomateiro cultivado. No entanto, esforços adicionais de melhoramento serão necessários para transferir para o tomateiro cultivado os fatores de resistência identificados em outros acessos de S. peruvianum, uma vez que existem barreiras naturais de cruzamentos entre estas duas espécies