Needle trap devices (NTDs), like solid-phase microextraction (SPME) fibers, represent a new approach to one-step, solvent-free sample preparation and injection. New NTDs, packed with divinylbenzene (DVB) or Carboxen 1000 particles, are prepared, characterized, and used for benzene, toluene, ethylbenzne, and xylene (BTEX) sampling in our laboratory. This paper describes optimization parameters, performance evaluation, and application of NTDs for the analysis of a BTEX mixture from air. For active sampling, a sampling flow rate is an essential optimization parameter. Using a very small amount of sorbent particles (less than 1mg DVB or Carboxen), 1.9 mL/min was the highest sampling flow rate that could be used with no breakthrough of any BTEX components. A single NTD was used to study breakthrough volumes (BTVs) and the breakthrough volume was proportional to the quantity of sorbent packed inside the needle. The Carboxen-packed NTD showed higher BTVs for all BTEX compared to the DVB-packed NTD. The performance of home-made NTDs was evaluated at different sampling flow rates, storage times, and for reusability. Finally, DVB packed NTDs were used to sample and analyze a BTEX mixture from permanent marker fumes, mosquito coil smoke, and at various points in the interior of a house. A very low concentration (10 pg/mL) of toluene was detected in the garage.
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http://dx.doi.org/10.1016/j.chroma.2008.02.090 | DOI Listing |
Vet Parasitol
January 2025
Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi Province 030801, PR China. Electronic address:
Toxoplasma gondii, an obligate intracellular protozoan, infects almost all warm-blooded animals and humans, with felines serving as its sole definitive hosts. Cats release T. gondii oocysts into the environment through feces, contributing to environmental contamination that can lead to toxoplasmosis in humans upon exposure through ingestion of contaminated food, water, or soil.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Chemical Engineering, University of Florida, Gainesville, FL 32611.
We describe a microfluidic device to extract DNA from a cell lysate, without the need for centrifuges, magnetic beads, or gels. Instead, separation is driven by transverse migration of DNA, which occurs when a polyelectrolyte solution flowing through a microfluidic channel is subjected to an electric field. The coupling of the weak shearing with the axial electric field is highly selective for long, flexible, charged molecules, of which DNA is the sole example in a typical cell lysate.
View Article and Find Full Text PDFAnalyst
January 2025
Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, 70803, USA.
Various technical methodologies are required to accurately detect substances of different chemical and pharmacological properties in biological samples, which are increasing in number and variety daily. Therefore, laboratories where many samples and different factors are analyzed simultaneously need methods with easy sample preparation, short analysis times and low analysis costs. In this study, the objective was to scan substances susceptible to chemical degradation, amenable to analysis without hydrolysis, and exhibiting short-term stability by employing a straightforward, expeditious, and cost-efficient method.
View Article and Find Full Text PDFSmall
January 2025
Department of Chemistry, Fudan University, Shanghai, 200438, China.
Rapid and sensitive detection of Epstein-Barr virus cell-free DNA (EBV cfDNA) is crucial for early diagnosis and monitoring of nasopharyngeal carcinoma (NPC), but accessibility to screening is limited by complicated and costly conventional DNA isolation and purification approaches. Here, a fully integrated ion concentration polarization (ICP)-enriched and nanozyme-catalyzed lateral flow assay (ICP-cLFA) is developed, enabling total analysis of EBV cfDNA in whole blood samples, with DNA isolation, pre-concentration, and amplification performed on a microfluidic chip, consequently providing the signal readout within 75 min. Specifically, ICP preconcentration and amplification steps, together with target recognition catalyzed by a platinum-decorated mesoporous gold nanosphere (MGNS@Pt) nanozyme, result in an ultralow detection limit of 4 aM in standard cfDNA samples and 100 aM in whole blood from NPC-bearing rats.
View Article and Find Full Text PDFMethods Protoc
January 2025
The Center for Forensic Science Research and Education, 206 Welsh Road, Horsham, PA 19440, USA.
This differential extraction protocol details the steps for isolating DNA from sample pads used in lateral flow immunochromatographic (LFI) tests, particularly for cases involving mixed biological samples such as semen and menstrual blood, or other evidence related to sexual assault. This procedure utilizes a differential extraction technique applied to sample pads from immunochromatographic tests, where the sample pads serve as the substrate. The method involves two sequential lysis steps to effectively separate non-sperm and sperm fractions, enabling the targeted isolation of distinct cell types for downstream DNA analysis.
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