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1.
Anal Bioanal Chem ; 412(3): 611-620, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31900539

RESUMO

Infections caused by foodborne microorganisms are a great threat to the global environment and public healthcare today. Thus, rapid, portable and sensitive assays that can realize the identification of foodborne bacteria are highly desired. In this study, a smart fluorescent and colorimetric dual-readout sensing system has been established for simple and rapid E. coli determination by utilizing the Cu2+-triggered oxidation of o-phenylenediamine (OPD). Initially, Cu2+ can oxidize OPD to OPDox, resulting in an orange-yellow fluorescence and visible pale-yellow color. However, E. coli can effectively reduce Cu2+ into Cu+, inhibiting the Cu2+-triggered oxidation of OPD to OPDox. Consequently, the introduction of E. coli can turn off both the fluorescence and the UV-vis absorbance signals of the OPD-Cu2+ system, illustrating an original mechanism for fluorescent and colorimetric dual-channel detection of E. coli. Moreover, a filter paper-based visual sensor was built and coupled with OPD-Cu2+ solution under the assistance of a UV lamp. The as-prepared sensor can detect E. coli quantitatively with the help of a typical smartphone color-scanning application (APP). Thus, this study offers a valid dual-mode assay for sensitive and on-site visible detection of E. coli, guaranteeing the reliability of the results and is more attractive for practical use. Graphical Abstract Schematic illustration of the smartphone-integrated sensing system for fluorescent and colorimetric dual-channel detection of E. coli based on the Cu2+-OPD system.


Assuntos
Bactérias/isolamento & purificação , Colorimetria/métodos , Corantes Fluorescentes/química , Microbiologia de Alimentos , Papel , Smartphone , Espectrometria de Fluorescência/métodos , Integração de Sistemas , Bactérias/patogenicidade , Técnicas Biossensoriais , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta/métodos
2.
Sci Total Environ ; 703: 135577, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767313

RESUMO

Plastic biodegradable mulch (plastic BDM) is tilled after use, but there is concern about incomplete degradation and potential impact on subsequent crops, and we lack a reliable method to measure mulch degradation post soil-incorporation. We conducted two field experiments to (i) develop a sampling method to estimate the amount of mulch (fragments size >2.36 mm) in the field post soil-incorporation, and (ii) assess the amount of BDM in the soil after four consecutive years of mulch incorporation. In Expt. 1, we used the quartering method to reduce soil from a 1 m2 field sample area to a representative 19 L sample. In Expt. 2, we applied and tilled four plastic BDMs: BioAgri, Naturecycle, Organix AG, and an experimental mulch; and one paper mulch, WeedGuardPlus, in their respective plots for four consecutive years. Starting in year 2, we sampled soil with the quartering method each spring and fall to determine mulch recovery. With respect to the total amount of mulch applied, average mulch recovery in the fall for the three commercial plastic BDMs was 71%, 50%, and 35% after second, third and fourth applications, respectively. For the experimental mulch, the average recovery was 80%, 69%, and 54% in the fall after second, third, and fourth applications, respectively. Recovery was slightly lower in spring than in preceding fall all years. For WeedGuardPlus, average recovery was 14%-20% in each fall, and no recovery in any spring (complete degradation). The results show that the quartering method reliably estimates the amount of mulch in a field and BDMs degrade over time in the field even with repeated applications, but complete degradation takes >1 year. While a few standards (e.g., ASTM D5988) specify how to determine biodegradation of plastics in soil under controlled laboratory conditions, our sampling method assesses plastic degradation under diverse field conditions.


Assuntos
Plásticos Biodegradáveis , Biodegradação Ambiental , Papel , Monitoramento Ambiental , Microbiologia do Solo
3.
J Chromatogr A ; 1609: 460437, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31409488

RESUMO

Thermal papers (e.g. point of sale receipts, adhesive labels, tickets) significantly contribute to contamination of paper material cycles and the environment with substances of (eco-) toxicological concern. In particular, they contain color developers like endocrine disrupting bisphenols in typical concentrations of about 1-2 percent per weight (wt%). Bisphenol A (BPA) was used as the common color developer over the last decades, but it will be restricted for thermal paper application in the European Union to a limit of 0.02 wt% from 2020 onwards. Consequently, a variety of BPA substituents such as bisphenol S (BPS) and its derivatives gain importance in thermal paper application. In this study, a rapid, reliable and cost-effective method for identification and quantification of BPA, alternative color developers and related substances like sensitizers is presented based on HPLC separation coupled with diode array detection (DAD) and Corona charged aerosol detection (CAD). Quantification was performed with regard to the intended use of the substances in thermal papers. Besides traditional UV external calibration using reference standards, alternative quantification approaches, in particular UV chromophore concentration for BPS derivatives and CAD universal response technique for low-volatile color developers, were applied and compared in order to allow quantification without reference substances. A market analysis for intended used color developers and sensitizers was performed on thermal paper samples (n = 211) collected in Germany during 2018 and 2019. Pergafast 201 (in 41.7% of the samples) was the most common color developer with concentrations above 0.02 wt%, followed by BPA (36.0%), BPS (13.3%) and other BPS derivatives known as D8, D-90, BPS-MAE and TGSA, that are mainly present in adhesive labels. Sensitizers were determined in over 90% of the samples.


Assuntos
Aerossóis/análise , Compostos Benzidrílicos/análise , Marketing , Papel , Fenóis/análise , Temperatura Ambiente , Compostos Benzidrílicos/química , Calibragem , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Cor , Disruptores Endócrinos/análise , União Europeia , Alemanha , Limite de Detecção , Modelos Lineares , Fenóis/química , Padrões de Referência , Sulfonas
4.
Sci Total Environ ; 702: 134376, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31726345

RESUMO

Pulp and paper mill sludge (PPMS) mainly consists of primary sludge and secondary sludge (activated sludge). Before the disposal and utilization of PPMS, it is dewatered due to high water content. Cellulose fiber is a key and characteristic component in PPMS. In this paper, the role of cellulose fiber on the dewaterability of simulated PPMS (the mixture of cellulose fibers and activated sludge) was investigated, including the fiber content, fiber length and fibrillation degree. The results showed that the specific resistance to filtration (SRF) of simulated PPMS decreased with the increase of fiber content (0-30 w%) and also decreased with the decrease of average fiber length (0.597-0.303 mm) noticeably. However, the SRF increased dramatically when the average fiber length reduced further to 0.189 mm. The fiber fibrillation had no obvious effect on the sludge SRF. Besides, the addition of cellulose fiber had little impact on the sludge compressibility. The role of cellulose fiber in the PPMS is to form aggregates with high fiber-sludge adhesion and large floc size, which relieves the blinding effect and changes the permeability of sludge cake respectively, resulting in improving sludge filterability.


Assuntos
Papel , Celulose , Filtração , Eliminação de Resíduos Líquidos/métodos
5.
Carbohydr Polym ; 227: 115380, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31590848

RESUMO

Old corrugated containers with low recyclability were used as raw materials to synthesize a series of aerogels with varying cellulose concentrations in NaOH/urea solution via a freeze-drying process. The resulting aerogels had a rich porous structure with specific surface areas in the range of 132.72-245.19 m2.g-1 and mesopore volumes in the range of 0.73-1.53 cm3.g-1, and were tested for CO2 sorption at ambient temperature and pressure, displaying excellent CO2 adsorption capacities in the range of 1.96-11.78 mmol.g-1. Furthermore, the CO2/N2 selectivity of aerogels decreased with decreasing specific surface area, which was mainly caused by the decrease in CO2 capture. In addition, the CO2 sorption capacity of the sample with 2% cellulose content, CA-2, exceeded the values reported so far for many other sorbents with higher specific surface areas, and showed reasonable cyclic stability for CO2 capture. Therefore, this adsorbent represents an attractive prospect for CO2 uptake at room temperature.


Assuntos
Dióxido de Carbono/química , Sequestro de Carbono , Celulose/química , Adsorção , Géis , Papel , Porosidade , Reciclagem , Hidróxido de Sódio/química , Ureia/química
6.
J Photochem Photobiol B ; 203: 111746, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31884349

RESUMO

Bovine metabolic diseases are silent clinical conditions caused by a disturbance in normal cellular metabolic processes majorly due to the demand for nutrients, physiological stress and inflammation in lactating animals. Even though these are non-devastating diseases, conditions like mastitis and ketosis highly influence cow's lactation and fertility performance that leads to economic losses. Hence, in the present study, a combined detection including a sensitive paper-based colorimetric device for the rapid determination of somatic cells (SCC) and electrochemical detection of ß-hydroxybutyrate (BHB) in the milk samples has been developed. The working range was 1 × 105 to 2 × 106 for SCC and 0.05 to 2.5 mM BHB in which the normal and extreme cases of mastitis and ketosis values exist. The detection method is based on reaction using substrate 5-Bromo-indoxyl acetate (5BIA) and enzyme (BHB dehydrogenase) for the enzymes (esterase) and substrate (BHB) present in the milk samples during mastitis and ketosis respectively. An increase in blue color development was associated with an increase in the number of SCC; likewise, the increased voltage denoted the increase concentration of BHB in the samples. The repeatability was evaluated, and the % relative standard deviation (RSD) value <8.0 (n = 12). The limit of detection (LOD) was close to that achieved by a desktop spectrophotometer. The applicability of the developed kit demonstrated good sensitivity that can be deployed for other biological samples of interest. The proposed method provides a rapid, sensitive and promising tool for the regular monitoring of cows as a point of care tests (POC) at the field level.


Assuntos
Técnicas Eletroquímicas/métodos , Cetose/diagnóstico , Mastite/diagnóstico , Leite/química , Ácido 3-Hidroxibutírico/análise , Animais , Bovinos , Colorimetria , Eletrodos , Feminino , Limite de Detecção , Leite/citologia , Papel , Testes Imediatos
7.
Anal Chim Acta ; 1094: 47-56, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31761047

RESUMO

A new planar sorptive phase based on the simple immobilization of polymeric ionic liquids on paper is proposed. The sorptive phase can develop hydrophobic or mixed-mode (combining hydrophobic and ion exchange) interactions with the target analytes. The polymer is prepared by the Radziszewski reaction, which takes place in aqueous media, and it has been thoroughly characterized by different techniques including infrared spectroscopy, matrix-assisted laser desorption/ionization coupled to high-resolution mass spectrometry and proton nuclear magnetic resonance. Three different strategies aimed to immobilize the polymeric ionic liquid on paper have been evaluated. Among them, simple thermal curing at 120 °C was selected. The as-prepared paper has been evaluated for the extraction of several non-steroidal anti-inflammatory drugs from urine, the analytes being finally determined by liquid chromatography with tandem mass spectrometry. The method detection limits were 3.8, 7.2, 6.8, 9.4, 15.7, and 5.1 µg/L for indomethacin, diclofenac, tolmetin, ketoprofen, naproxen, and ibuprofen, respectively. Calibration models were linear (R2 > 0.9949) up to 1000 µg/L. The intra-day precision, expressed as relative standard deviation and calculated at three different concentrations levels (limit of quantification, 250 µg/L, and 1000 µg/L), varied between 1.1 and 13%. The accuracy, calculated as relative recovery, was in the range from 72 to 95%, thus being considered appropriate. The easiness of polymeric ionic liquid paper synthesis and the multi-sample extraction protocol designed allows the processing of a high number of samples at the same time.


Assuntos
Anti-Inflamatórios não Esteroides/urina , Imidazóis/química , Líquidos Iônicos/química , Papel , Polímeros/química , Adsorção , Cromatografia Líquida , Humanos , Imidazóis/síntese química , Líquidos Iônicos/síntese química , Limite de Detecção , Polímeros/síntese química , Microextração em Fase Sólida/instrumentação , Microextração em Fase Sólida/métodos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrometria de Massas em Tandem
8.
Forensic Sci Int ; 306: 110002, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31864775

RESUMO

Designer drugs or new psychoactive substances (NPS) are a heterogeneous group of substances obtained through the modification of chemical structure of some natural products or drugs. NPS illegally commercialized in blotter papers mimicking the most common form of LSD consumption, with a great variability of colours and symbols, have largely increased worldwide, including in Brazil, becoming an important emerging public health issue. In this study, we have evaluated the presence and profile of NPS in blotters seized in the State of Santa Catarina, Brazil, over the period of 2011 to 2017. The state government criminal forensics staff has performed gas chromatography-mass spectrometer (GC-MS) analyses in order to determine the chemical composition of the blotters. During the evaluated period, there was a considerable increase in the seizing of blotters events, from 87 in 2011, to 301 in 2016 and reaching 277 in 2017. There was also an increase in the number of blotters seized per event. Interestingly, while in 2011, 100% of blotters contained LSD, this number decreased to 0,1% in 2014, and achieved 17,6% in 2017, when up to 25 different substances were detected in blotters seized. Drugs such as DOx, NBOMe, fentanyl, mescaline derivatives, triptamines, cathinones, and synthetic cannabinoids were detected and became the major substances found in blotters. In some cases, more than one substance was found in the same blotter, characterizing a new mixture scenario. The presence of several new psychoactive substances in blotters is a reality in forensic toxicology. In Brazil, it might be related to the fact that most of these substances were not considered illegal by Brazilian legislation by the time they emerged.


Assuntos
Drogas Desenhadas/análise , Papel , Psicotrópicos/análise , Brasil/epidemiologia , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Dietilamida do Ácido Lisérgico/análise , Estudos Retrospectivos , Transtornos Relacionados ao Uso de Substâncias/epidemiologia
9.
Crit Rev Food Sci Nutr ; 60(1): 157-170, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-30311773

RESUMO

As a representative colorimetic biosnesor, paper-based LFSA have emerged as a promising and robust tool that can easily and instansly detect the presence of target biological components in food sample. Recently, LFSAs have gained a considerable attention as an alternative method for rapid diagnosis of foodborne pathogens to the conventional culture-based assays such as plate counting and PCR. One major drawback of the current LFSAs for the detection of pathogenic bacteria is the low sensitivity, limiting its practical applications in POCT. Not like many other protein-based biomarkers that are present in nM or pM range, the number of pathogenic bacteria that cause disease can be as low as few CFU/ml. Here, we review current advances in LFSAs for the detection of pathogenic bacteria in terms of chromatic agents and analyte types. Furthermore, recent approaches for signal enhancement and modifications of the LFSA architecture for multiplex detection of pathogenic bacteria are included in this review, together with the advantages and limitations of each techniques. Finally, the technological challenges and future prospect of LFSA-based POCT for the detection of pathogenic bacteria are discussed.


Assuntos
Bactérias/isolamento & purificação , Técnicas Biossensoriais , Contaminação de Alimentos/análise , Microbiologia de Alimentos/métodos , Colorimetria/instrumentação , Papel
10.
J Appl Microbiol ; 128(1): 161-170, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31609034

RESUMO

AIMS: The utilization of micro-organisms in pulp and paper industries has proved biobleaching technology as an environmentally friendly alternative to the conventional approach. In this paper, the effect of actinobacterial fermentation broth on pulp biobleaching has been investigated. METHODS AND RESULTS: Actinobacterial colonies were isolated from lignocellulose-rich soil samples and screened for xylanase production and bleaching activity. The most efficient isolate in bleaching activity showed 100% similarity to Streptomyces rutgersensis. Pulp treatment with 5-day fermentation broth of this strain showed up to 7% increase in brightness (30°C for 6 h, pH (5-7)) compared to untreated (control) pulp. Also, after 60 min biotreatment, significant reduction (12·5%) in consumption of bleaching chemicals was achieved to obtain final brightness of 55%. CONCLUSION: Actinobacterial fermentation broth can be considered as a rich source of effective biobleaching agents which may be considered as environmental friendly and cost-effective technique in comparison with traditional method. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings showed ability of S. rutgersensis UTMC 2445 in bleaching chemomechanical paper pulp. Also, two strains of Saccharothrix, a rare actinobacterium, with biobleaching activity were introduced. In the proposed method, there is no need to use purified enzymes, and biobleaching process can be done using the fermentation broth.


Assuntos
Clareadores/metabolismo , Lignina/análise , Papel , Solo/química , Streptomyces/metabolismo , Actinomycetales/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Fermentação , Concentração de Íons de Hidrogênio , Lignina/metabolismo , Microbiologia do Solo , Streptomyces/enzimologia , Temperatura Ambiente
11.
Talanta ; 207: 120346, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594588

RESUMO

Acute myocardial infarction (AMI) causes significant mortality and morbidity. The determination of multiple AMI biomarkers is very important for the timely diagnosis of AMI. In this work, simultaneous determination of three AMI biomarkers were achieved by virtue of a three-dimensional (3D) microfluidic paper-analytical device (µPAD) with temporally resolved chemiluminescence (CL) emissions for the first time. A dual-signal amplification strategy was introduced including by employing primary antibody functionalized gold nanoparticles (Ab1-GNPs) immobilized on the detection zone as amplified capture probes, and Co(II) catalyst, secondary antibody, luminol multifunctionalized gold nanoparticles (Co(II)-Ab2-luminol-GNPs) with excellent CL activity as amplified signal probes. CL immunoreactions were performed at three detection zone of the fabricated 3D µPAD by assembling Ab1-GNPs, antigen, and Co(II)-Ab2-luminol-GNPs to form sandwich-type immunocomplexes. Auto separated CL signals with temporal resolution were obtained by time delayed transport of H2O2 to different detection zones for multiplexed analysis. The CL signal obtained by using Co(II)-Ab2-luminol-GNPs as signal probe (10576 a.u.) were about 20-fold higher than that by using conventional horseradish peroxidase labeled antibody modified luminol-GNPs as signal probe (531 a.u.). Finally, three AMI biomarkers including heart-type fatty acid-binding protein (H-FABP), cardiac troponin I (cTnI) and copeptin were quantitatively analyzed in one CL detection run by reading the CL intensity of the obtained three CL emission peaks. The detection range were ultra-wide ranged from 0.1 pg/mL to 1 µg/mL, 0.5 pg/mL to 1 µg/mL and 1 pg/mL to 1 mg/mL with the detection limits down to 0.06 pg/mL, 0.3 pg/mL and 0.4 pg/mL for H-FABP, cTnI and copeptin detection, respectively. The developed µPAD based immunoassay performing multiplexed analysis ability, high sensitivity, ultra-wide dynamic range, favorable selectivity, accessible accuracy and reproducibility, have great application potential for the early diagnosis of AMI.


Assuntos
Ouro/química , Imunoensaio/instrumentação , Dispositivos Lab-On-A-Chip , Medições Luminescentes/instrumentação , Nanopartículas Metálicas/química , Infarto do Miocárdio/metabolismo , Papel , Doença Aguda , Biomarcadores/análise , Biomarcadores/sangue , Biomarcadores/química , Técnicas Biossensoriais/instrumentação , Humanos
12.
Food Chem ; 309: 125792, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31711806

RESUMO

Seven commercial samples, consisted of plastic bags, tetrabrik and box, were evaluated by gas chromatography-olfactometry-mass spectrometry (GC-O-MS) to find the compounds responsible for off-odors in different PP, PE, multilayer cardboard and paper materials used for food contact. Migration assays were carried out with Tenax as food simulant to analyze the food safety as well as to evaluate the odor intensity after migration assay. Forty six compounds with characteristic odors were directly found in the materials studied. The strongest odors identified were acetic, propanoic and butyric with vinegar and rancid odors and octanal, nonanal and decanal with fat/soup odors, all of them found in PP and PE samples. Trimethylbenzenes with solvent and oily odors as well as terpenes with weakly woody odors were found in cardboard and paper materials. After migration, all compounds were below the European Legislation limits and maximum migration values recommended by Cramer. However propanoic, acetic and butyric acid as well as aldehydes compounds, phenol and 1-octanol were detected by sniffers, after migration assay, with high modified frequency (between 50 and 78%), what could change the organoleptic properties of packaged food.


Assuntos
Embalagem de Alimentos , Odorantes/análise , Olfatometria/métodos , Polietileno/química , Polipropilenos/química , Aldeídos/análise , Contaminação de Alimentos/análise , Cromatografia Gasosa-Espectrometria de Massas , Papel , Fenóis/análise
13.
BMJ ; 367: l6343, 2019 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-31699685
14.
PLoS Negl Trop Dis ; 13(11): e0007842, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31738760

RESUMO

BACKGROUND: Reduced susceptibility of mosquito vectors to currently used insecticides hampers control interventions. Recently pyriproxyfen, an insect growth regulator has been demonstrated to effectively reduce the reproductive potential in vector mosquitoes. METHODS: Pyriproxyfen (PPF), in different concentrations (0.75%, 0.075%, 0.0075%, and 0.00075%) was applied on papers and Indian wild type Aedes aegypti female mosquitoes (N ≥ 20 for each treatment) were exposed onto it as per WHO guidelines, to study the reproductive disruption. PPF concentration on treated papers was quantitatively cross-determined using HPLC method. Reduction in fecundity, fertility and adult emergence in exposed female Ae. aegypti was determined. Abnormal development in ovary and eggs of exposed females was studied microscopically after different time intervals. RESULTS: Eggs laid, eggs hatched, pupae formed and adults emerged per female exposed in both before blood meal and after blood meal groups declined significantly from lowest to highest concentration of PPF (F ≥ 5.2; p < 0.02). Adult emergence inhibition in females exposed to PPF before and after blood meal groups ranged from 58.8% [OR = 0.18 (95% CI = 0.09-0.36)] to 79.2% [OR = 0.04 (95% CI = 0.02-0.10)] and 64.4% [OR = 0.12 (95% CI = 0.05-0.28)] to 77.1% [OR = 0.05 (95% CI = 0.02-0.14)] respectively in different concentrations. The probit model used suggested that FI50 (50% fertility inhibition) and EI50 (50% emergence inhibition) were 0.002% (p = 0.82) and 0.0001% (p = 0.99) for females exposed before blood meal, while 0.01% (p = 0.63) and <0.0001% (p = 0.98) for the females exposed after blood meal, respectively. The eggs laid by the females exposed to PPF-treated surface showed altered body organization, desegmentation and disoriented abdominal and cervical regions in the developing embryo. Quantification of PPF on impregnated papers showed that it was uniformly distributed throughout the matrix. CONCLUSIONS: The present study has shown that tarsal contact to PPF-treated surface for a small time drastically influenced the fecundity, fertility and adult emergence in Indian wild Ae. aegypti mosquitoes. Results suggest that a certain minimum concentration of PPF through contact exposure can reduce the abundance of vector mosquitoes to a considerable level. The formulations based on combination of PPF and other compatible insecticides may be an impactful approach where susceptible mosquitoes are killed by the insecticide component while resistant mosquitoes are sterilised by PPF.


Assuntos
Aedes/efeitos dos fármacos , Inseticidas/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Piridinas/farmacologia , Animais , Cromatografia Líquida de Alta Pressão , Feminino , Fertilidade/efeitos dos fármacos , Inseticidas/análise , Ovário/efeitos dos fármacos , Papel , Piridinas/análise , Reprodução/efeitos dos fármacos , Propriedades de Superfície , Zigoto/efeitos dos fármacos
15.
Chem Commun (Camb) ; 55(91): 13753-13756, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31663548

RESUMO

A chemosensor containing an o-hydroxyaniline unit as the reaction site was developed for colorimetric and fluorimetric detection of phosgene, which showed fast response (15 s), high specificity, and an extremely low detection limit. The chemosensor was incorporated into paper strips for visual detection of phosgene vapor.


Assuntos
Papel , Fosgênio/análise , Espectrometria de Fluorescência/métodos , Corantes Fluorescentes/química , Gases/química , Limite de Detecção
16.
Anal Chim Acta ; 1087: 104-112, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31585557

RESUMO

The current work describes the development of a "nanopaper-based analytical device (NAD)", through the embedding of curcumin in transparent bacterial cellulose (BC) nanopaper, as a colorimetric assay kit for monitoring of iron and deferoxamine (DFO) as iron-chelating drug in biological fluids such as serum blood, urine and saliva. The iron sensing strategy using the developed assay kit is based on the decrease of the absorbance/color intensity of curcumin-embedded in BC nanopaper (CEBC) in the presence of Fe(III), due to the formation of Fe(III)-curcumin complex. On the other hand, releasing of Fe(III) from Fe(III)-CEBC upon addition of DFO as an iron-chelating drug, due to the high affinity of this drug to Fe(III) in competition with curcumin, which leads to recovery of the decreased absorption/color intensity of Fe(III)-CEBC, is utilized for selective colorimetric monitoring of this drug. The absorption/color changes of the fabricated assay kit as output signal can be monitored by smartphone camera or by using a spectrophotometer. The results of our developed sensor agreed well with the results from a clinical reference method for determination of Fe(III) concentration in human serum blood samples, which revealed the clinical applicability of our developed assay kit. Taken together, regarding the advantageous features of the developed sensor as an easy-to-use, non-toxic, disposable, cost-effective and portable assay kit, along with those of smartphone-based sensing, it is anticipated that this sensing bioplatform, which we name lab-on-nanopaper, will find utility for sensitive, selective and easy diagnosis of iron-related diseases (iron deficiency and iron overload) and therapeutic drug monitoring (TDM) of iron-chelating drugs in clinical analysis as well.


Assuntos
Celulose/química , Desferroxamina/análise , Quelantes de Ferro/análise , Ferro/análise , Smartphone , Colorimetria/instrumentação , Colorimetria/métodos , Curcumina/química , Desferroxamina/sangue , Desferroxamina/urina , Humanos , Ferro/sangue , Ferro/urina , Nanoestruturas/química , Papel , Saliva/química
17.
Forensic Sci Int ; 304: 109969, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31593907

RESUMO

The new psychoactive substances (NPS) in Colombia are detected by national authorities, in blotters strip, in different circumstances and places: airports, music concerts, discos and parks. Blotters are marketed as LSD and cause several cases of intoxication and death in some consumers: due to acute intoxication or when mixed with other drugs and may have different effects on the central nervous system (CNS). This study was conducted to research into and identify the chemical composition of the drugs impregnated in the blotters sold in two Colombian cities. This research provides the analysis of 70 doses coming from forensic cases of the Colombian Attorney General's Office in Bogota and from the Laboratory of Narcotics of the Colombian National Institute of Legal Medicine and Forensic Sciences (North Headquarter) in Barranquilla. Mixtures of drugs, such as DOB, 25I-NBOMe, MDMA and 25I-NBOMe imine were found within the blotters through gas chromatography coupled to mass spectrometry (CGMS); these drugs are classified by international authorities as NPS belonging to the phenylethylamines group. The results clearly warn about a growing public health problem in the country.


Assuntos
2,5-Dimetoxi-4-Metilanfetamina/análogos & derivados , Dimetoxifeniletilamina/análogos & derivados , Tráfico de Drogas , N-Metil-3,4-Metilenodioxianfetamina/isolamento & purificação , 2,5-Dimetoxi-4-Metilanfetamina/isolamento & purificação , Administração Sublingual , Colômbia , Drogas Desenhadas/isolamento & purificação , Dimetoxifeniletilamina/isolamento & purificação , Contaminação de Medicamentos , Humanos , Papel , Transtornos Relacionados ao Uso de Substâncias
18.
Analyst ; 144(21): 6382-6390, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31576382

RESUMO

An accurate quantification method with a wide linearity range is paramount for the development of low-cost, portable and point-of-care sensors. This work reports a new approach to analyze the colorimetric assays on paper-based sensors using the quantification from a light transmission method. Compared to the commonly-developed color intensity measurement on scanned digital images, a portable transmission densitometer is capable of directly quantifying the optical density of colorimetric results. The detection of heavy metals in an aqueous system, including Fe(ii), Cu(ii), and Ni(ii), was carried out to demonstrate the good performance and reliability of this method. Our measurements show that the linear quantification range spans from 0.5-500 mg L-1 for the assays of Cu(ii) and Fe(ii) and from 2-500 mg L-1 for Ni(ii) based on the reading of transmitted light through the assay spot. As a comparison, the linear range is restricted to 0.5-50 mg L-1 for the same assays when analysed by the common reflection method, suggesting a significant improvement in the accuracy and sensitivity of high analyte concentrations from the light transmission method. By expanding the linearity range, this method further streamlines the sampling procedure during analysis and will greatly advance the future development of paper-based analytical sensors.


Assuntos
Colorimetria/instrumentação , Luz , Limite de Detecção , Metais Pesados/agonistas , Fenômenos Ópticos , Papel , Desenho de Equipamento , Reprodutibilidade dos Testes
19.
Anal Chim Acta ; 1089: 56-65, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31627819

RESUMO

A novel all-in-one paper-based sampling concept for mass spectrometric bottom-up protein analysis is here demonstrated in a chip format integrating instant immunocapture, protein reduction, - alkylation and tryptic digestion all in-device. Conventional laboratory grade filter paper was coated with the polymer 2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone (pHEMA-VDM) with a subsequent covalent immobilization of the monoclonal antibody E27 targeting the biomarker human chorionic gonadotropin (hCG). In-device protein reduction and alkylation was optimized with regards to reagent concentration and reaction pH. The sampling concept showed a high degree of performance between 10 and 1000 ng/mL (R2 > 0.99) by a five-point calibration curve sampled with hCG spiked to human serum samples and freshly collected whole blood samples, respectively. LOD (experimentally obtained at 100 pg/mL (2.64 pM/0.9 IU/L)) was demonstrated to be up to ten times lower with more than six times faster sample preparation than what has previously been reported for on-paper analysis of hCG in human serum samples.


Assuntos
Gonadotropina Coriônica/sangue , Teste em Amostras de Sangue Seco/métodos , Papel , Sequência de Aminoácidos , Anticorpos Imobilizados/imunologia , Anticorpos Monoclonais/imunologia , Biomarcadores/sangue , Biomarcadores/química , Gonadotropina Coriônica/química , Gonadotropina Coriônica/imunologia , Cromatografia Líquida , Teste em Amostras de Sangue Seco/instrumentação , Humanos , Limite de Detecção , Espectrometria de Massas/instrumentação , Espectrometria de Massas/métodos , Proteólise , Reprodutibilidade dos Testes , Tripsina/química
20.
Analyst ; 144(21): 6291-6303, 2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31549693

RESUMO

In the emergency diagnosis of patients, acute myocardial infarction (AMI) is always time-consuming to diagnose, and the process requires multiple laboratory procedures, expensive equipment and skilled workers. Herein, we developed an easy-to-use, low-cost and portable fluorescent lateral flow immunoassay based on paper microfluidics for the point-of-care diagnostics of non-communicable diseases. The fluorescent lateral flow immunoassay can produce results in less than 10 minutes, and the limit of detection (LOD) is 0.019 ng ml-1. The slope was linear from 0 to 100 ng ml-1; the equation is y = 0.0342e2.1181x and R2 = 0.9618, which are distinctive features that ensure maximum amplification of the signal and recording of quantitative values by an analyser. The detection sensitivity showed an exceptional increase to 0.01 ng ml-1. Compared with conventional bioassay readers, our analyser shows some advantages to easily, clearly and effectively read data. The present point-of-care test for cardiac troponin I decreases the turnaround time and has a high coefficient of variation even at lower concentrations of troponin. So, the development of lateral flow assay-based point-of-care assays with higher analytical performance for real world samples can decrease the rule-out time for AMI in emergency departments and other fields.


Assuntos
Técnicas e Procedimentos Diagnósticos/instrumentação , Imunoensaio/instrumentação , Dispositivos Lab-On-A-Chip , Doenças não Transmissíveis , Papel , Sistemas Automatizados de Assistência Junto ao Leito , Colódio/química , Membranas Artificiais , Miocárdio/metabolismo , Espectrometria de Fluorescência , Troponina T/análise , Troponina T/metabolismo
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