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Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies.

A highly selective two-point separation strategy was designed based on a cross-like all-in-one lab-on-paper analytical device. The stable and cleavable enzyme-coated reduced graphene oxide (rGO)–PdAu probe was fabricated as the signal reporter to enable the visualization and electrochemiluminescence (ECL) dual-mode sensing of Pb2+. Concretely, the experimental workflow consists of the following process: (i) fabrication of the lab-on-paper device and growth of Au nanoparticles on ECL detection zone, (ii) immobilization of Pb2+-specific DNAzyme, and (iii) hybridization between DNAzyme and rGO–PdAu–glucose oxidase (GOx) labeled oligonucleotide to form the double-stranded DNA. Upon addition of Pb2+ into the prepared system, the double-helix structure of the DNA was destroyed, resulting in the release of cleaved rGO–PdAu–GOx probe to visualization bar to promote the effective oxidation and color change of 3,3′,5,5′-tetramethylbenzidine. As a consequence, the color change can be recognized by naked eye, meanwhi...

Low cost disposable working electrodes are specifically desired for practical applications of electrochemical detection considering maturity of electrochemical stations and data collection protocols. In this paper double-sided conductive adhesive carbon tape with nanostructure was applied to fabricate disposable working electrodes. Being supported by indium tin oxide glass, the prepared carbon tape electrodes were coated with bismuth film for stripping analysis of heavy metal ions. By integrating the bismuth modified electrodes with paper-based analytical devices, we were able to differentiate Zn, Cd and Pb ions with the sample volume of around 15 μL. After the optimization of parameters, including modification of bismuth film and the area of the electrodes, etc., Pb ions could be measured in the linear range from 10 to 500 μg/L with the detection limit of 2 μg/L. Our experimental results revealed that the disposable modified electrodes could be used to quantify migrated lead from toys with the results agreed well with that using atomic absorption spectrometry. Although bismuth modification and stripping analysis could be influenced by the low conductivity of the carbon tape, the low cost disposable carbon tape electrodes take the advantages of large-scaled produced double-sided carbon tape, including its reproducible nanostructure and scaled-up fabrication process. In addition, the preparation of disposable electrodes avoids time-consuming pretreatment and experienced operation. This study implied that the carbon tape might be an alternative candidate for practical applications of electrochemical detection.

Lab-on-paper (LOP) devices are urgently required for the rapid development of point-of-care diagnoses and environmental assays. Herein, an all-sealed paper-based electrochemiluminescence (ECL) platform was developed to achieve lead ions (Pb2+) sensitive analysis via incorporating convenient plastic package technology. Benefiting from transparent plastic encapsulation, the sealed devices effectively avoided the interference of O2. Meanwhile, myrica rubra-like Pt nanomaterials (MPNs) prepared by an economical and easy-to-operate ultrasound method were employed to catalyze H2O2 decomposition. With the help of Pb2+-specific DNAzymes, the oligonucleotide probe functionalized via MPNs could be detached from the device in the presence of target, resulting in the reduced ECL intensity. Moreover, the combination of modified paper electrode with functional regions separated by multiple layers of wax enhanced the practicability of the LOP device for rapid detection. Under the optimal conditions, the all-sealed platform achieved wide linear relationship ranging from 0.01 nM to 0.05 μM with a low detection limit of 0.004 nM for sensitive detecting Pb2+. It is believed that this platform could provide a robust, simple and versatile strategy for sensitive determination of heavy metal ions, and be applied in on-site contamination analysis in the future.

A multi-amplified paper-based electrochemical strategy using Pb(2+) dependent DNAzyme as the recognition unit for Pb(2+) detection was developed. In this work, flower-like reduced graphene (FrGO) was prepared utilizing flower-like ZnO as template, which was first one step grown on the gold nanoparticles modified paper working electrode (Au-PWE). After being treated with acid and then modified with Au, a novel sensor platform named Au/FrGO/Au-PWE with large specific surface area and good electrical conductivity was fabricated. The Mn2O3 nanoparticle-assembled hierarchical hollow spheres (H-Mn2O3) was served as nanocarrier to immobilize GOx, HRP and signal strand (S3), resulting to the formation of S3/H-Mn2O3/HRP/GOx bioconjugations. In the presence of Pb(2+), the DNAzyme (S1) was activated and the substrate strand (S2) was cleaved. After the incubation with S3/H-Mn2O3/HRP/GOx in 0.1M HAc-NaAc solution (pH 4.3) containing 30 mM aniline and 15 mM glucose, a readily measurable "turn-on" electrochemical signal could be measured. On the basis of the signal amplification strategy of Au/FrGO/Au-PWE sensing platform and S3/H-Mn2O3/HRP/GOx bioconjugations, the developed biosensor exhibited a good linear response toward over a wide range of concentration from 0.005 to 2000 nM.

The possibility of amending Pb2+ contaminated soil (S) with paper sludge (P) was investigated through adsorption and desorption experiments. The adsorption process of Pb2+ in soil containing paper sludge (SP) could be well described by pseudo second-order kinetic model and the Langmuir isotherm model. After P addition, the equilibrium time decreased greatly (from 28 to 8 hr) and the Pb2+ maximum adsorbed amount (Qmax) increased by a factor of more than three to 102.04 mg/g. Qmax reached its maximum as S:P was 9:1 (m/m) after 10 days contact between S and P. Moreover, Pb2+ adsorbed amount increased with the rise of pH during the adsorption process. Desorption experiments indicated that Pb2+ adsorption in SP was irreversible. The metal ion fraction was analyzed with Energy Dispersive Spectrometer and Environmental Scan Electron Microscope. As a result, the addition of P to soil was found to induce a decrease in the mobile forms. The Pb2+ complexes formation in the presence of carbonates was the main adsorption mechanism. Overall, the paper sludge could be one of the promising soil amendments for the remediation of soil with Pb2+ contamination.

Background Lack of a second sample often precludes the ability to perform repeat lead measurements on filter paper bloodspot samples. We investigated whether annular specimens remaining from once-punched filter paper bloodspot specimens could provide accurate Pb measurements when measurements were scaled for the remainder area relative to the original punch area. Methods 50 μl bloodspot specimens were prepared using Pb-spiked EDTA whole blood. After removal of 6 mm punches, bitmap images of the remainder specimens were obtained using a scanner. Image analysis was used to determine the bloodspot area of the remainder sample relative to the area of the original punch. Measurement of Pb for punches and for remainder specimens was performed by ICP-MS. Results Area-corrected Pb measurements for remainder samples were significantly higher than for the punches, by an average factor of 1.52 ± 0.12 ( p n = 28). The difference was due to a discontinuity (an increase) in the per-area Pb at the bloodspot perimeter. Area-corrected results for annular specimens that excluded the perimeter were identical to those of the punch. Conclusion Area-corrected Pb measurement using annular once-punched bloodspot remainder specimens can accurately reproduce lead measurements obtained from the original punch when the bloodspot perimeter area is excluded.

Background Sample collection instructions for the bloodspot lead screening program conducted by the Nebraska Medical Center recommend continuous application of a single finger-stick blood drop per printed filter paper circle (a volume of approximately 50 μl). In this study, we assessed whether apparent blood volumes and geometries of finger-stick bloodspot samples submitted for lead testing were consistent with collection recommendations. Methods Samples were 422 extra bloodspots from 138 patients that were submitted for lead analysis. Using image analysis, apparent blood volumes were computed by comparison of bloodspot areas to bloodspot areas for standards of known volume. Circularity of samples was also assessed by image analysis. Results Mean blood volume (25 ± 13 μl) was approximately 50% of that needed to fill a printed circle. The distribution of volumes had three local maxima, consistent with bloodspot formation by multiple discrete applications of blood drops of small volumes (17 ± 6 μl) rather than by continuous application of blood. Multi-drop samples were also apparent from non-circular geometries. Conclusions Bloodspots submitted for lead analysis showed an apparently inherent drop volume of less than 20 μl per drop and the application of multiple drops. Non-ideality of such specimens indicates the need for continuing education of bloodspot collectors.

Material conversion from paper sludge ash (PSA) in NaOH solution was attempted to synthesize the adsorbent for removal of inorganic pollutants, such as Pb2+, NH4+ and PO4(3-) from aqueous solution. PSA of 0.5 g was added into 10 mL of 3 mol/L NaOH solution, and then heated at 80, 120, and 160 degrees C for 6-48 hr to obtain the product. PSA mainly composed of two crystalline phases, gehlenite (Ca2Al2SiO7) and anorthite (CaAl2Si2O8), and amorphous phase. Hydroxysodalite (Na6Al6Si6O24 8H2O) was formed at 80 degrees C, and anorthite dissolved, whereas gehlenite remained unaffected. Katoite (Ca3Al2SiO4(OH)8) was formed over 120 degrees C, and hydroxycancrinite (Na8(OH)2Al6Si6O24 2H2O) was formed at 160 degrees C, due to the dissolution of both gehlenite and anorthite. Specific surface areas of the products were almost same and were higher than that of raw ash. Cation exchange capacities (CECs) of the products were also higher than that of raw ash, and CEC obtained at lower temperature was higher. Removal abilities of products for Pb2+, NH4+, and PO4(3-) were higher than that of raw ash. With increasing reaction temperature, the removal efficiencies of Pb2+ and NH4+ decreased due to the decrease of CEC of the product, while removal efficiency for PO4(3-) was almost same. The concentrations of Si and Al in the solution and the crystalline phases in the solid during the reaction explain the formation of the product phases at each temperature.

Made available in DSpace on 2018-12-11T17:25:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-10-01. Added 1 bitstream(s) on 2019-10-09T18:32:11Z : No. of bitstreams: 1 S0103-50532015001002137.pdf: 734176 bytes, checksum: 7fee879dc45f5fc8d0fd7a74eb8ce9b4 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) A simple, inexpensive, and clean methodology employing a combined spot test/diffuse reflectance spectroscopy procedure was developed and applied for the quality control analysis of lead in hair dyes, using a filter paper platform. The method is based on the complexation reaction of lead, present in a pH 2.8 buffer medium containing tartaric acid and sodium and potassium tartrate, with sodium rhodizonate (ROD) in an aqueous medium containing sodium dodecyl sulfate (SDS) surfactant, yielding a colored compound on the surface of a filter paper. The concentrations of ROD and SDS were optimized using experimental design. The linear range obtained for reflectometric measurements carried out at 545 nm was 4.70-140 mg L-1 of lead (R = 0.998), and the limits of detection and quantification were 1.12 and 3.75 mg L-1 , respectively. The proposed method was successfully applied to the analysis of lead in progressive hair dyes. Instituto de Química, Universidade Estadual Paulista, UNESP, Rua Prof. Francisco Degni 55, CP 355 Instituto de Química, Universidade Estadual Paulista, UNESP, Rua Prof. Francisco Degni 55, CP 355

Residual dried blood spots (DBSs) on filter paper from neonatal screening have been proposed as samples for population survey of lead contamination. We have investigated the EDTA effect on lead release in the eluting solution.Furnace atomic absorption spectrophotometry has been used for lead measurements. Standard, blank and sample solutions contained 2% m/v NH(4)H(2)PO(4), 0.5% v/v Triton X-100 and 0.2% v/v HNO(3) as matrix modifier solution (MMS) with or without EDTA. A calibration curve was established from aqueous standard solutions. Paper discs from DBS and blank, punched near the DBS, were eluted in MM solution and, where required, EDTA at different concentrations. Specimens were leftover DBSs with different storage times, matched samples from 20 adult patients consisting of liquid whole blood (LWB) containing 5 mmol/L EDTA, DBSs eluted in MM solution with 5 mmol/L EDTA or without EDTA.Optimal lead recovery from DBS required 5 mM EDTA in the eluting solution. Mean lead levels of LWB and DBSs eluted with EDTA were similar and higher than DBSs without EDTA (P0.001). Without EDTA, the median value of lead optical density was lower for 6-month-old DBSs than for blanks (P0.001).Residual DBSs can be used for population survey, but 5 mmol/L EDTA in the extracting solution is required to fully recover lead.

Screening programs for pediatric lead (Pb) poisoning routinely collect blood by finger stick onto specially designed filter paper (FP) for subsequent laboratory testing. Here, laser ablation inductively coupled plasma time-of-flight mass spectrometry is evaluated as a novel method for the determination of Pb in blood spotted onto FP cards. The method requires no sample pretreatment and may be particularly suitable for rapidly screening a large number of samples. Signal intensity from the ICP-MS strongly correlated (r (2) = 0.996) with Pb target values for five blood cards from a laboratory proficiency testing program. Better precision was obtained by replicate ablation line scans (15% rsd) compared to a grid of 25 individual ablation spots (30% rsd). Because2% of the sample is consumed in the laser ablation analysis, selected samples can also be analyzed by traditional techniques or archived. Lead isotope ratios determined during the same total-Pb analysis appear to be effective for discerning contamination extraneous to the blood sample. Determining that an elevated result was due to contamination may negate the need for retesting with invasive pediatric venipuncture. Some elements monitored along with Pb exhibited signal profiles conducive to potential quantitation (Ca, V, Fe, Cu Zn), whereas others did not (Cr, Mn, Co, Ni, Cd, Hg, Tl, U). Copper, Ca, and V were inversely correlated with Pb (r = -0.89, -0.90, and -0.92, respectively). Scanning electron microscope images revealed surface modality differences between FP spotted with fresh whole blood and reconstituted freeze-dried blood reference material.