Human Standard Reference Material Research Articles

Standardization of two SARS-CoV-2 serology assays to the WHO 20/136 human standard reference material

WHO 20/136 is standard reference material for SARS−COV-2 serology assays. Standardization of serology assays that target the same antigen and class of immunoglobulin will enable comparison of results between studies that use various lab-developed and commercial assays around the world. Standardization of assays will help better define immune correlates of protection and possibly immune correlates of vaccine efficacy. Two automated SARS−COV-2 anti-S1 RBD immunoglobulin serology assays on the Atellica IM Analyzer were calibrated to WHO 20/136 Standard Reference Material which was assigned 1000 binding antibody units (BAU/mL). The anti-S1 RBD IgG assay (sCOVG) cut-off Index of 1.00 corresponded to WHO 45.1 BAU/mL, and the anti-S1 RBD Ig Total assay (COV2T) cut-off Index of 1.00 corresponded to WHO 6.70 BAU/mL.

On-line Ultrasound-Assisted Dispersive Micro-Solid-Phase Extraction Based on Amino Bimodal Mesoporous Silica Nanoparticles for the Preconcentration and Determination of Cadmium in Human Biological Samples.

On-line ultrasound-assisted dispersive micro-solid-phase extraction (USA-DμSPE) has been developed for preconcentration and separation of trace amounts of Cd(II) ions in 0.5mL of human biological samples. In a syringe with a nylon membrane, new synthetic bulky amino bimodal mesoporous silica nanoparticles (NH2-UVM7) were dispersed as a nanoadsorbent in 5mL of diluted serum sample (1:10), and after ultrasonic shaking, the liquid phase was separated from the solid phase. At the optimized pH, the chemical and physical adsorption of cadmium ions occurred, respectively, based on complexation with amine groups of UVM7 (Cd:NH2-UVM7) and silica nanoparticles. The analyte was then back-extracted from the sorbent with nitric acid solution (0.2M), and its concentration was determined by electrothermal atomic absorption spectrometry (ETAAS). Under the optimized conditions, the linear range, limit of detection (LOD), and preconcentration factor (PF) were obtained as 0.01-0.56μgL(-1), 0.002μgL(-1), and 25, respectively. The adsorption capacity of NH2-UVM7 was found to be 108.6mgg(-1) of cadmium. The validation of the methodology was performed by the human standard reference material (HSRM).