Poly(ethylene glycol) functionalization of monolithic poly(divinyl benzene) for improved miniaturized solid phase extraction of protein-rich samples

Non-specific protein adsorption on hydrophobic solid phase extraction (SPE) adsorbents can reduce the efficacy of purification. To improve sample clean-up, poly(divinyl benzene) (PDVB) monoliths grafted with hydrophilic polyethylene glycol methacrylate (PEGMA) were developed. Residual vinyl groups (RVGs) of the PDVB were employed as anchor points for PEGMA grafting. Two PEGMA monomers, Mn 360 and 950, were compared for graft solutions containing 5–20% monomer. Protein binding was qualitatively screened using fluorescently labeled human serum albumin (HSA) to determine optimal PEGMA concentration. The fluorescent signal of PDVB was reduced for PDVB-g-PEGMA360 (10%) and PDVB-g-PEGMA950 (20%). The PEGMA content (w/w%) was quantified by solid state 1H NMR to be 29.9 ± 1.6% for PDVB-g-PEGMA360 and 7.7 ± 1.2% for PDVB-g-PEGMA950. To assess adsorbent performance breakthrough curves for PDVB, PDVB-g-PEGMA360 and PDVB-g-PEGMA950 were compared. The breakthrough volume (VB) and shape of the curve for PDVB-g-PEGMA950 were maintained relative to PDVB (2.3 and 2.8 mL, respectively). A reduced VB of 0.5 mL and shallow breakthrough curve indicated PDVB-g-PEGMA360 was not suitable for SPE. A high ibuprofen recovery of 92 ± 0.30 and 78 ± 0.93% was seen for PDVB and PDVB-g-PEGMA950, respectively. Protein adsorption was reduced from 31 ± 2.41 to 12 ± 0.49% for PDVB and PDVB-g-PEGMA950, respectively. SPE of ibuprofen from plasma was compared for PDVB and PDVB-g-PEGMA950 by at-line electrospray ionization mass spectrometry (ESI-MS). PDVB-g-PEGMA950 demonstrated a threefold increase in assay sensitivity indicating a superior analyte purification

Hydrogeochemistry of Isti Su Hot Spring, Western Azerbaijan, Iran

The Isti Su hot spring is located in southeast of Salmas, in Western Azerbaijan, Iran. The area is a small part of Sanandaj–Sirjan geological zone which hosts many hot springs. The magma chamber of Salmas region is the main heat source of the hot springs in Isti Su area. Abundant rainfall and relatively long duration of snowfall as well as several deep faults in the area create the best conditions to have several hot springs in the area. The host rocks of the area are sedimentary and metamorphic rocks of Cambrian to Recent sediments which are intruded by several granite and ophiolite bodies. Several hot springs have been formed in the vicinity of these plutonic to sub-volcanic bodies. The Isti Su hot spring is one of the most typical hot springs of the Salmas region. Eight samples were collected from the study area. To investigate the seasonal changes in the field and chemical parameters and to measure trace element concentrations in dry and wet seasons, springs were sampled twice in May and November. Temperature, pH and electrical conductivity of the water samples were measured on-site. Temperatures of the selected samples range from 26.3 to 38.5 °C. The pH values of the samples vary between 6.4 and 7.5. TDS contents range from 9200 to 1790 mg/L. The results of geochemical analysis show that the As, Li, Fe, Hg, Na, and Cr are not more than WHO’s standard level. As and B are two times more than WHO’s standard level. The As and B concentrations in the hydrothermal and geothermal solutions rise higher than its standard level. World Health Organization recommended As level for drinking water is 0.01 mg/L. The Na–SO4–HCO3 triangular diagram shows that the samples are of HCO3 and Na types. Open skin scars, gangrene, malignant cancers and environmental problems are among the consequences of high concentrations of As and B. The high content of As and B in water of this hot spring can be harmful to the environment and people of the area