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A new kind of ambient ionization method named superhydrophobic preconcentration paper spray ionization mass spectrometry (SHPPSI MS) is introduced, where superhydrophobicity and paper spray mass spectrometry (PS MS) are coupled. The SHPPSI MS requires only microliter amounts of analyte solutions, allows easy sampling procedure, and provides high sensitivity for a diverse array of analytes. It can be used to detect food adulteration at extremely low concentrations. The experimental methodology involves modifying one of the surfaces of a triangularly cut filter paper to make it acquire low surface energy by drop casting a green and ecofriendly superhydrophobic coating material over it followed by drying. A micrometer scale defect was made at close proximity to one of the tips of the paper using a pin. Preconcentration of the sample was accomplished by allowing a 10 μL droplet of an aqueous solution of the analyte to stand at the defect followed by drying naturally. The dried paper was used as the substrate for paper spray mass spectrometry by eluting the analyte with a suitable solvent. This novel technique was used to detect melamine in adulterated milk, whose detection at the ppt level in milk normally needs sophisticated instruments, a larger amount of sample, and a complex sampling procedure, including further purification and separation. The SHPPSI MS detects melamine directly from milk at the sub-ppb level by simply putting a microdroplet of adulterated milk at the substrate and eluting the sample with methanol. This paper-based technique can be a promising tool for direct sensing of analytes such as drugs in body fluids, pesticides in water and soil, etc.

A novel hydrophobic-SERS substrate platform based on silver nanoparticles (AgNPs) functionalized commercially available filter paper was reported. Compared with conventional substrates, not only could this novel SERS substrate meet the requirements of simple and large-scale preparation, but also realized direct droplet-detection with reusable property. In this work, the fabrication, physical characterization, and SERS sensitivity of the substrates to spot-on food determination were studied. The experimental results show the method exhibited high reproducibility with less than 9% spot-to-spot variation in Raman intensity. Furthermore, the method was successfully applied to detect melamine in diluted milk with the instrument detection limit (IDL) down to 1 ppm in a linear correlation (1 ppm–1000 ppm). In addition, this SERS substrate could also be applied successfully in other fields, such as the determination of pesticide (thiram) and dye (malachite green) in real environment.

In this study, we have developed a method for rapid, highly efficient and selective detection of melamine. The negatively charged citrate ions form an electrostatic layer on gold nanoparticles (AuNPs) and keep the NPs dispersed and stable. When citrate-capped AuNPs were further modified with Triton X-100, it stabilized the AuNPs against the conditions of high ionic strength and a broad pH range. However, the addition of melamine caused the destabilization and aggregation of NPs. This may be attributed to the interaction between melamine and the AuNPs through the ligand exchange with citrate ions on the surface of AuNPs leading Triton X-100 to be removed. As a result, the AuNPs were unstable, resulting in the aggregation. The aggregation induced a wine red-to-blue color change, and a new absorption peak around 630 nm appeared. Triton X-100-AuNPs could selectively detect melamine at the concentration as low as 5.1 nM. This probe was successfully applied to detect melamine in milk. Furthermore, paper-based quantitative detection system using this colorimetric probe was also demonstrated by integrating with a smartphone.

Benzaldehyde-functional cellulose paper sheets have been synthesized via tosylation of cellulose (Whatman No 5) followed by addition of p-hydroxy benzaldehyde. Via UV-induced Paterno-Buchi [2+2] cycloaddition reactions, these aldehyde functional surfaces are grafted with triallylcyanurate, trimethylolpropane allyl ether, and vinyl chloroacetate. In the following, allyl-functional polymers (poly(butyl acrylate), pBA, Mn = 6990 g mol(-1) , Đ = 1.12 and poly(N-isopropyl acrylamide), pNIPAAm, Mn = 9500 g mol(-1) , Đ = 1.16) synthesized via reversible addition fragmentation chain transfer polymerization are conjugated to the celloluse surface in a UV-induced grafting-to approach. With pBA, hydrophobic cellulose sheets are obtained (water contact angle 116°), while grafting of pNIPAAm allows for generation of "smart" surfaces, which are hydrophilic at room temperature, but that become hydrophobic when heated above the characteristic lower critical solution temperature (93° contact angle). The Paterno-Buchi reaction has been shown to be a versatile synthetic tool that also performs well in grafting-to approaches whereby its overall performance seems to be close to that of radical thiol-ene reactions.

The integration of paper with an electrochemical device has attracted growing attention for point-of-care testing, where it is of great importance to fabricate electrodes on paper in a low-cost, easy and versatile way. In this work, we report a simple strategy for directly writing electrodes on paper using a pressure-assisted ball pen to form a paper-based electrochemical device (PED). This method is demonstrated to be capable of fabricating electrodes on paper with good electrical conductivity and electrochemical performance, holding great potential to be employed in point-of-care applications, such as in human health diagnostics and food safety detection. As examples, the PEDs fabricated using the developed method are applied for detection of glucose in artificial urine and melamine in sample solutions. Furthermore, our developed strategy is also extended to fabricate PEDs with multi-electrode arrays and write electrodes on non-planar surfaces (e.g., paper cup, human skin), indicating the potential application of our method in other fields, such as fabricating biosensors, paper electronics etc.

An offender who has recently handled bulk explosives would be expected to deposit latent fingermarks that are contaminated with explosive residues. However, fingermark detection techniques need to be applied in order for these fingermarks to be detected and recorded. Little information is available in terms of how routine fingermark detection methods impact on the subsequent recovery and analysis of any explosive residues that may be present. If an identifiable fingermark is obtained and that fingermark is found to be contaminated with a particular explosive then that may be crucial evidence in a criminal investigation (including acts of terrorism involving improvised explosive devices). The principal aims of this project were to investigate: (i) the typical quantities of explosive material deposited in fingermarks by someone who has recently handled bulk explosives; and (ii) the effects of routine fingermark detection methods on the subsequent recovery and analysis of explosive residues in such fingermarks. Four common substrates were studied: paper, glass, plastic (polyethylene plastic bags), and metal (aluminium foil). The target explosive compounds were 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), as well as chlorate and nitrate ions. Recommendations are provided in terms of the application of fingermark detection methods on surfaces that may contain explosive residues.

A simple and efficient ambient ionization method based on paper spray combined with tandem mass spectrometry allows rapid detection and quantitation of various contaminants (clenbuterol, melamine, plasticizer and sudan red) in various foodstuffs (e.g., meat, milk, sports drinks and chili powder).

Melamine paper is a basic material used in the furniture industry for home and office interiors. Contact allergic dermatitis from melamine formaldehyde resins (MFRs) should be considered in patients who work on melamine paper impregnation lines. We report a case of a 28-year-old female plywood worker who developed eczema on the dorsal side of her hands and wrists after 2 years of working on the melamine paper impregnation line. She had a relevant positive patch-test reaction to MFR, with a negative reaction to formaldehyde. Contact dermatitis due to MFR is not common, and it is usually related to products that are not fully cured or to close contact with intermediate products on the assembly line. Formaldehyde release from MFR can explain most of the positive responses. To our knowledge, this is the first report of MFR contact allergic dermatitis in a worker on a melamine paper impregnation line.

Because of spore formation, Bacillus anthracis is considered the most resistant biological warfare agent known. The present study aimed to assess and compare well-known decontamination routes to inactivate the spores on daily-use environmental tools contaminated previously. To simulate the agent, Bacillus atrophaeus was used. Various environmental samples (such as tile, fabric clothing, wood, protective suit, glass, paper, soil, water, plastic, and metal) that may be contaminated after a biological incident were used as test carriers and inoculated with B. atrophaeus. Sodium hypochlorite, free chlorine, autoclaving, ethylene oxide, hydrogen peroxide, ultraviolet irradiation, and boiling decontaminated the samples. Glutaraldehyde (2%) and free chlorine solution (10,000 mg/L) were also found to be effective in decontaminating the samples and are recommended as alternatives to the use of sodium hypochlorite solution. Soil, tile, paper, and metal were determined to be the most difficult materials to decontaminate. It was concluded that 5% hypochlorite adjusted with acetic acid might also be used for decontamination. Decontamination strategies to reduce contamination of the environment by biological warfare agents need to be applied to mitigate the number of victims, in terms of prominent characteristics like cost-effectiveness and user-friendliness.

To examine a large population with idiopathic generalised epilepsy (IGE), and estimate the overall remission rates for the IGEs and subsyndromes in a clinic based sample. Remission rates on valproate, lamotrigine, topiramate, and combinations of these antiepileptic drugs were estimated and factors predicting outcome examined.All patients with IGE were identified from a computerised database and EEG records at large adult and paediatric epilepsy clinics. Data were recorded retrospectively on demographics and clinical information, seizure types and syndrome diagnosis, antiepileptic drug treatment details, and remission rates.54.3% of 962 patients had achieved a one year period of remission; this was most likely with valproate monotherapy (52.1%), with lower rates for lamotrigine and topiramate (16.7% and 34.6%, respectively). The combination of valproate and lamotrigine achieved a remission rate of 15.3%. The factor most predictive of a response to a particular antiepileptic drug regimen was the rank order in which it was given. Relapse rate was high (79.9%) after antiepileptic drug withdrawal in remission, particularly with juvenile myoclonic epilepsy (93.6%).Valproate may be the most effective antiepileptic drug in the treatment of the IGEs. Combination therapy should be initiated if an adequate trial of valproate monotherapy is not effective, rather than switching to alternative monotherapy. Antiepileptic drug treatment needs to be lifelong in many adult patients with IGE.

An improved method is presented for the determination of proguanil, cycloguanil and 4-chlorophenylbiguanide in 100-μl capillary blood samples applied to sampling paper. This method also utilises a solid-phase extraction technique and high-performance liquid chromatography. Different kinds of sampling paper, such as ion-exchange and cellulose sampling paper were tested. The best elution recovery (70–80%) was obtained after treatment of cellulose sampling paper with a quaternary ammonium compound. The limit of determination was 50 nmol/l for cycloguanil and 4-chlorophenylbiguanide and 125 nmol/l for proguanil using 100 μl capillary blood. The stability of the analytes and elution performance from sampling paper was validated at different temperature and storage time. Venous blood and capillary blood concentrations of proguanil and metabolites were found to be similar.

A novel two-dimensional cyanuric chloride-activated (CCA) paper has been developed. It is composed of a cellulosic base, covalently bound cyanuric chloride, and microprecipitated complex cyanuric chloride-sodium chloride crystals on its surface. CCA paper covalently binds nucleic acids and proteins. Its binding capacity for nucleic acids is about 400 micrograms/cm2. Sealed into nitrogen-filled bags and stored at -20 degrees C, it retains its binding activity for at least a year and is always ready for use. CCA paper has been successfully used for capillary and electroblotting of DNA, RNA, and proteins (Southern, Northern, and Western blotting) as well as for dot tests. Furthermore, it was applied to colony and plaque hybridization. A unique property of it is that it permits the staining of proteins after blotting and subsequent performance of radioimmunological detection of specific protein components. This has proven advantageous in two-dimensional Western blotting experiments. Of further importance is its ability to bind DNA fragments from one up to several hundred bp from polyacrylamide sequencing gels.

Conditions for the optimal use of cyanuric chloride-activated (CCA) paper in Southern transfer hybridization experiments of genomic DNA were investigated. They depend critically on pH and ionic strength during transfer and on the composition of the hybridization solution. Simplified hybridization conditions using a SSC/dextran sulfate system at 65°C without sodium dodecyl sulfate and the complex Denhardt's solution are applied. CCA paper allows repeated use in hybridization experiments. Under optimized conditions CCA paper allows a more sensitive detection of single-copy gene sequences in the subpicogram range than do nylon membranes. Application of these transfer and hybridization conditions with our newly developed CCA paper to carrier determination and prediction of the healthy male haplotype demonstrates its usefulness for prenatal counseling of a Duchenne muscular dystrophy family.