Background: Ethinylestradiol (EE) is the active component in most birth control products. It is especially difficult to analyze due to the presence of many closely related endogenous steroids. Endogenous components can coelute with EE making selective extraction and chromatographic separation challenging. Current MS systems are more sensitive to background, contamination and the overall cleanliness of samples and solvents, placing additional emphasis on sample preparation methodology.
Method: UPLC was combined with a sensitive triple quadrupole MS and a three-step sample preparation method to highlight and resolve method development challenges.
Results: EE was adequately resolved using an unendcapped high-strength silica C(18) column. The average matrix factor in six sources of plasma was 1.14 with a %CV of 4.48. Standard curves were linear with 1/x weighting and r(2) value of 0.999 over three orders of magnitude. Average accuracy for standard curves and quality control samples was 96%. LOD of 0.001 ng/ml was achieved.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.4155/bio.12.29 | DOI Listing |
J Food Sci
January 2025
Department of Human Nutrition, Food, and Animal Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA.
Freezing extends the shelf life of foods but often leads to structural damage due to ice crystal formation, negatively impacting quality attributes. Oscillating magnetic field (OMF)-assisted supercooling has emerged as a potential technique to overcome these limitations by inhibiting ice nucleation and maintaining foods in a supercooled state. Despite its potential, the effectiveness and underlying mechanisms of OMF-assisted supercooling remain subjects of debate.
View Article and Find Full Text PDFJ Food Sci
January 2025
Nutrition Research Center, Department of Food Science and Technology, Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran.
Alternatives to nonbiodegradable synthetic plastics for food packaging include films made from biopolymers that are nontoxic and environment-friendly. In this study, carnauba wax (CW) and nitrogen-doped graphene quantum dots (NG) as functional additives were utilized in the production of pectin/gelatin (PG) film. NG was synthesized through the microwave method, using acetic acid as the carbon source, giving size, and zeta potential of 1.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Hebei Lansheng Bio-Tech Co, Ltd, Shijiazhuang, 052263, P. R. China.
A novel fluorescence sensing nanoplatform (CDs/AuNCs@ZIF-8) encapsulating carbon dots (CDs) and gold nanoclusters (AuNCs) within a zeolitic imidazolate framework-8 (ZIF-8) was developed for ratiometric detection of formaldehyde (FA) in the medium of hydroxylamine hydrochloride (NHOH·HCl). The nanoplatform exhibited pink fluorescence due to the aggregation-induced emission (AIE) effect of AuNCs and the internal filtration effect (IFE) between AuNCs and CDs. Upon reaction between NHOH·HCl and FA, a Schiff base formed via aldehyde-diamine condensation, releasing hydrochloric acid.
View Article and Find Full Text PDFJ Exp Zool B Mol Dev Evol
January 2025
Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Saint Petersburg, Russia.
Colonial invertebrates consist of iterative semi-autonomous modules (usually termed zooids) whose lifespan is significantly shorter than that of the entire colony. Typically, module development begins with budding and ends with degeneration. Most studies on the developmental biology of colonial invertebrates have focused on blastogenesis, whereas the changes occurring throughout the entire zooidal life were examined only for a few tunicates.
View Article and Find Full Text PDFAnal Methods
January 2025
School of Pharmacy, Wannan Medical College, Wuhu 241002, China.
A label-free photoelectrochemical (PEC) sensor for detecting theophylline (TP) was exploited based on electrodes modified with a nanocomposite of polydopamine nanospheres (PDSs) and gold nanoparticles (AuNPs). PDS particles were prepared by oxidative autopolymerization, and their reducibility was utilized in one step to reduce the gold nanoparticles . The AuNPs-PDS/ZnS PEC sensor was constructed by electrochemical deposition and drop coating.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!