HF Medium Research Articles

Chicoric acid attenuates hyperglycemia-induced endothelial dysfunction through AMPK-dependent inhibition of oxidative/nitrative stresses

Background Endothelial dysfunction is a driving force during the development and progression of cardiovascular complications in diabetes. Targeting endothelial injury may be an attractive avenue for the management of diabetic vascular disorders. Chicoric acid is reported to confer antioxidant and anti-inflammatory properties in various diseases including diabetes. However, the role and mechanism of chicoric acid in hyperglycemia-induced endothelial damage are not well understood. Methods In the present study, human umbilical vein endothelial cells (HUVECs) were incubated with high glucose/high fat (HG + HF) to induce endothelial cell injury. Results We found that exposure of HUVECs to HG + HF medium promoted the release of cytochrome c (cytc) from mitochondrion into the cytoplasm, stimulated the cleavage of caspase-3 and poly ADP-ribose-polymerase (PARP), then inducing cell apoptosis, the effects that were prevented by administration of chicoric acid. Besides, we found that chicoric acid diminished HG + HF-induced phosphorylation and degradation of IκBα, and subsequent p65 NFκB nuclear translocation, thereby contributing to its anti-inflammatory effects in HUVECs. We also confirmed that chicoric acid mitigated oxidative/nitrative stresses under HG + HF conditions. Studies aimed at exploring the underlying mechanisms found that chicoric acid activated the AMP-activated protein kinase (AMPK) signaling pathway to attenuate HG + HF-triggered injury in HUVECs as AMPK inhibitor Compound C or silencing of AMPKα1 abolished the beneficial effects of chicoric acid in HUVECs. Conclusion Collectively, chicoric acid is likely protected against diabetes-induced endothelial dysfunction by activation of the AMPK signaling pathway. Chicoric acid could be a novel candidate for the treatment of the diabetes-associated vascular endothelial injury.

Anion Exchange Behaviour of Zr, Hf, Nb, Ta and Pa as Homologues of Rf and Db in Fluoride Medium

Studies of the chemical property of transactinide elements are very difficult due to their short half-lives and extremely small production yields. However it is still possible to obtain considerable information about their chemical properties, such as the most stable oxidation states in aqueous solution, complexing ability, etc., comparing their behaviour with their lighter homologous in the periodic table. In order to obtain a better knowledge of the behavior of rutherfordium, Rf (element 104), dubnium, Db (element 105) in HF medium, the sorption properties of Zr, Hf, Nb, Ta and Pa, homologues of Rf and Db, were studied in NH4F/HClO4 medium in this work. Stability constants of the fluoride complexes of these elements were experimentally obtained from Kd obtained at different F- and H+ concentrations. The anionic complexes: [Zr(Hf)F5]-, [Zr(Hf)F6]2-, [Zr(Hf)F7]3-, [Ta(Pa)F6]-, [Ta(Pa)F7]2-, [Ta(Pa)F8]3-, [NbOF4]- and [NbOF5]2- are present as predominant species in the HF range over investigation.
 

High Folic Acid Supplementation Reprograms Glycolytic and Lactate-generating Metabolism to Promote Anchorage-independent Tumor Spheroid Formation in NSCLC Cells (P05-001-19)

ObjectivesAims of this study were to investigate the effect of HF on anchorage-independent tumor spheroid formation and its’ working mechanisms of lung malignant tumor cells. MethodsHuman NSCLC cells A549 were cultured in control (C) medium (2.2 μM folic acid) or HF medium (10, 30, 50 μM folic acid) for 4 days. Cells were harvested to explore the self-renewal capacity of cancer cells by observing the anchorage-independent tumor spheroid formation. Meanwhile, the L-lactate assay were conducted to evaluate the lactate-generating state and the cell protein extract for the western blotting analysis to realize expression of energy metabolism related proteins in cells. ResultsThe results showed that numbers of tumor spheroids in HF group were significantly higher than the control group. Besides, compared to C group, HF50 group showed significantly reduced lactate release into medium with highly accumulation in cellular lactate levels. The glycolytic-related protein expression of hexokinase II (HKII), lactate dehydrogenase (LDH) were increased and glucose transporter 1 (GLUT1), pyruvate dehydrogenase (PDH) were decreased in HF group. The signaling-related protein expression of insulin receptor substract-1 (IRS-1), hypoxia-inducible factor-1 alpha (HIF-1α) were increased and PI3 kinase (PI3K), AMP-activated protein kinase (AMPK) were decreased in HF group. ConclusionsCollectively, HF supplementation may reprogram glycolytic metabolism and increase anchorage-independent tumor spheroids formation to mediate malignant progress of NSCLC. Funding SourcesMinistry of Science and Technology, Taiwan, R.O.C.

Gut Microbial Composition in Mice Fed Different Amount of Rice Resistant Starch (P21-031-19)

ObjectivesThe aim of this study is to evaluate the effects of rice containing different levels of resistant starch on the gut microbiome using a rodent model. MethodsRice with low resistant starch (0.11%), medium resistant starch (1.07%) and high resistant starch (8.61%) were cooked, grounded into powders and used to formulate diet to represent all the carbohydrates in mice diet that consist of low fat (LF, 10 kcal %) or high fat (HF, 39 kcal %). C57BL/6 mice (n = 60, male, 5 weeks old) were randomly assigned to six feeding groups: (1) low-fat and low resistant starch diet (LL); (2) high-fat and low resistant starch diet (HL); (3) low-fat and medium resistant starch diet (LM); (4) high-fat and medium resistant starch diet (HM); (5) low-fat and high resistant starch diet (LH); (6) high-fat and high resistant starch diet (HH). Mice were fed with diets for 8 weeks then gut microbiome composition was determined using 16S rDNA sequencing of cecal contents. ResultsWe found that the gut microbiome was significantly different at different levels of resistant starch (P < 0.01) but not at different fat levels. OTU (operational taxonomic unit) richness was reduced in LF and HF high-resistant groups as compared to others. OTU diversity was reduced in LF and HF medium and high-resistant groups as compared to low-resistant groups. Decreased Firmicutes to Bacteroidetes ratio, which related to lower risk of obesity, was observed in mice fed LF and HF high-resistant diet as compared to others. Moreover, at the family level, LF, HF high-resistant diet mainly increased the abundances of Bacteroidaceae and S24_7, the bacteria positively correlated with SCFAs (short-chain fatty acids) levels. We also observed a decrease in abundances of Odoribacteraceae, Rikenellaceae, Lachnospiraceae, Ruminococcaceae and Desulfovibrionaceae in LF and HF high resistant starch group. Desulfovibrionaceae and genus Odoribecter in Odoribacteraceae are reported to be opportunistic pathogens, Lachnospiraceae, Ruminococcaceae, Odoribacteraceae and Rikenellaceae are associated with obesity. ConclusionsOverall, our results demonstrated that resistant starch exerted concentration-dependent effect on the gut microbiome in mice which may have protective effect against obesity. Funding SourcesUSDA, ARS.

SYNTHESIS OF FLUORINE-CONTAINING ANALOGS OF ANESTHESINE AND NOVOKAINE

Methods for the synthesis of methyl, ethyl and butyl esters of meta- and para-pentafluoroethoxybenzoic acids starting with respective hydroxybenzoic acids have been developed. Firstly m- and p-hydroxybenzoic acids were esterificated with respective alcohol, and then obtained esters were treated with trifluoroacetic anhydride giving m- or p-alkyl trifluoroacetoxybenzoates that were treated with SF4 in anhydrous HF medium. Conditions for obtaining esters of meta- and para-pentafluoroethoxybenzoic acids with good yields have been discovered. It has been shown that the yields and ratios of the reaction products depend little on the size of the alkyl radical of the alkoxycarbonyl group, but substantially depend on the temperature, duration of the reaction, and the intensity of mixing. The lack of mixing of the reaction medium during treatment of m- and p-trifluoroacetoxybenzoates with SF4-HF leads to the cleavage of the trifluoroacetoxy group with the formation of the corresponding esters of m- and p-hydroxybenzoic acids. Increasing reaction temperature leads to formation of m- and p-pentafluoroethoxybenzotrifluorides in higher yields. Increasing duration of the reaction affects the same way. Anesthetic activity of obtained esters of meta- and para-pentafluoroethoxybenzoic acids was tested using white outbreed male mice. The esters have higher anesthetic activity compared to anesthesine. Ethyl para-pentafluoroethoxybenzoate exhibits the best anesthetic properties among the compounds obtained. meta-Pentafluoroethoxybenzoic acid has been obtained by means of hydrolysis of ethyl meta-pentafluoroethoxybenzoate. The acid has been treated with equimolar quantity of NaOH solution giving respective salt. The last one was then treated with 2-chloro-N,Ndiethylethanamine in DMF solution, giving analogue of novocaine with pentafluoroethoxy group in the meta-position of the benzene ring. Thus obtained novocaine analogue has also higher anesthetic activity compared to anesthesine.

Anodic Dissolution of Ti in Acidic Fluoride Media

Anodic dissolution kinetics of Ti in HF medium was investigated using potentiodynamic polarization experiments. The concentration of HF was varied and the effect of changing the H+ and F- ions independently by the addition H2SO4 and KF was also investigated. In all the cases, a clear active and passive regions were observed, and the peak current and potential exhibiting a systematic trend with increasing HF concentration. Scanning electron micrographs of electrodes held in the active and passive regions were acquired to characterize the surface morphology. Several mechanisms were evaluated to model the polarization data. A mechanism involving an chemical dissolution step in parallel with an electrochemical dissolution step was proposed to explain the results. The model captures all the major characteristics of the polarization curves. Based on the results, it is proposed that HF2 - is the key species which impacts the electrochemical dissolution and HF is the one which impacts the chemical dissolution process.

Properties and Suitability of East Aqaba Area Feldspar for Glass Industries in Jordan

In this study, a pegmatite ore with a Na2O/K2O (5.54-4.29) ratio of 1.29 was studied in a Denver flotation cell in which both at natural and acidic pH using HF and H2SO4. Because of the perthitic structure of the ore no significant separation is observed at natural pH. Interestingly, a selective separation was achieved at low pH using HF and H2SO4 (pH 2–3). a pegmatite ore composed of 5.53% Na2O and 4.29% K2O is upgraded to 10.51% Na2O and 6.59.02% K2O with a Na2O/K2O = 1.62 in HF medium and to 2.55 in H2SO4 medium. It is shown that products recovered in various stages are also considered as commercially significant; especially quartz which is recovered in the tailings in HF medium is suitable for glass industry.

Tantalum oxide honeycomb architectures for the development of a non-enzymatic glucose sensor with wide detection range

Tantalum oxide honeycomb nanostructures (THNS) were fabricated by electrochemical anodisation of tantalum in H2SO4–HF medium. XRD analysis showed that annealing of THNS at 400°C improves the crystallinity. HRSEM and AFM results illustrated that nanopores with an average diameter of 30nm were uniformly distributed and the pore size reduced to 24nm and 18nm during subsequent electrodeposition of Pt and CuO. Electrodeposited Pt and CuO exhibited face centered cubic (fcc) and monoclinic crystal structure respectively. Cyclic voltammetric studies revealed that, on the hybrid material electrooxidation of glucose occurs at a lower potential (0.45V). The sensor exhibited linear response to glucose up to 31mM, fast response time (<3s) and a low detection limit of 1μM (S/N=3). The sensor is free of interference from ascorbic acid, uric acid, dopamine and acetaminophen. Sensor was used to analyze glucose in blood serum samples.

Voltage enhancement in dye-sensitized solar cell using (001)-oriented anatase TiO2 nanosheets

A nanocrystalline TiO2 (anatase) nanosheet exposing mainly the (001) crystal faces was tested as photoanode material in dye-sensitized solar cells. The nanosheets were prepared by hydrothermal growth in HF medium. Good-quality thin films were deposited on F-doped SnO2 support from the TiO2 suspension in ethanolic or aqueous media. The anatase (001) face adsorbs a smaller amount of the used dye sensitizer (C101) per unit area than the (101) face which was tested as a reference. The corresponding solar cell with sensitized (001)-nanosheet photoanode exhibits a larger open-circuit voltage than the reference cell with (101)-terminated anatase nanocrystals. The voltage enhancement is attributed to the negative shift of flatband potential for the (001) face. This conclusion rationalizes earlier works on similar systems, and it indicates that careful control of experimental conditions is needed to extract the effect of band energetic on the current/voltage characteristics of dye-sensitized solar cell.

Modeling of the mechanism of one-electron transfer from the perylene molecule to the oxygen molecule 3O2 in the HF medium

The thermodynamic parameters of the formation of the perylene radical cation in anhydrous hydrogen fluoride containing dissolved dioxygen were calculated by the ab initio method MP2. The protonated product of HF autoprotolysis was modeled as the H(FH) 3 + cluster. The 3O2 molecule was found to bind to the linear H(FH) 3 + cluster via a hydrogen bond. As the charge and multiplicity of the system change upon the capture of an electron, the oxygen-hydrogen fluoride cluster complex undergoes rearrangement to yield the hydroperoxyl radical OOH incorporated in a cycle formed by HF molecules. The free energy of electron transfer from the perylene molecule to the 3O2 molecule in the HF medium is about −38 kcal/mol.

Preparation of SAPO-5 and Its Catalytic Synthesis of p-Aminophenol

Abstract Silicoaluminophosphate molecular sieves (SAPO-5) were synthesized by hydrothermal crystallization using both a conventional aqueous medium and a HF medium. The SAPO-5 samples were characterized by X-ray diffraction, scanning electron microscopy, solid state NMR, Fourier transform infrared reflectance spectroscopy, and temperature-programmed desorption of adsorbed NH3. The effect of Si content and presence of HF in the initial gel on the structure of the SAPO-5 synthesized and the manner of Si incorporation into the framework were investigated. Their acidity and catalytic activity for phenylhydroxylamine (PHA) rearrangement in the synthesis of p-aminophenol (PAP) from nitrobenzene were studied. The incorporation of Si in the samples prepared in the presence of HF was mainly by the SM3 mechanism and patches of Si(4Si) were predominant. This resulted in a decrease in the acid amount and increase in acid strength. The presence of HF during synthesis increased the integrity of the SAPO-5 crystal and helped incorporate more Si in the SAPO-5 structure by inhibiting the polymerization of Si species to a reticulated silica gel. The samples prepared in the HF medium exhibited better catalytic performance for PHA rearrangement in the synthesis of PAP, and a PAP yield of 53.2% could be obtained.

A comparative evaluation on the anodic behavior of Cu and Ag electrodes in non-aqueous fluoride and fluoroborate media

The voltammetric responses of copper and silver had been extensively studied and compared in a variety of non-aqueous solvents such as acetonitrile (AN), propylene carbonate (PC) and sulfolane containing two different supporting electrolytes namely triethylaminetrishydrogen fluoride (TEA.3HF) and tetrabutylammonium tetrafluoroborate (TBABF4). The dissolution rate and surface transformation on the electrode surfaces as a result of anodic polarization was investigated using atomic absorption spectroscopy (AAS) and scanning electron microscopy (SEM), respectively. In solvent-free TEA.3HF medium, the copper electrode shows high charge recovery ratio (Q c/Q a), and the difference between the initial anodic and cathodic potentials, obtained at a current density of 2 mA cm−2, is around 0.11 V, suggesting that in this medium, Cu can certainly serve as reference electrode. On the other hand, on Ag electrode, substantial dissolution was observed leading to very high anodic (Q a) and cathodic (Q c) charges, and the surface morphology after the cyclic polarization results in roughened surface with large pores. The effects of incorporating AN and water as additives in TEA.3HF on the solubility and stability of these metal fluoride films are also reported. The dissolution pattern and film formation behavior of these two metals in the different solvents containing fluoride and fluoroborate ionic species have several qualitative similarities, as noted from cyclic voltammetry responses and SEM morphology. Anodic dissolution and precipitation process for both Cu and Ag depends significantly on the nature of supporting electrolytes as well as solvents. In AN containing 0.1 M TEA.3HF, the dissolution of Cu and Ag electrodes was very high. Fluoride salts of Cu show lesser solubility than Ag in those solvents, while fluoroborate salts exhibit the reverse trend. The AAS data suggest that for a particular salt, which may be either fluoride or fluoroborate of Cu and Ag, the relative solubility decreases in the order AN > PC > sulfolane.

Characterization and hydroisomerization performance of SAPO-11 molecular sieves synthesized in different media

Abstract Silicoaluminophosphates SAPO-11 molecular sieves were synthesized from a conventional aqueous medium, a two-liquid phase medium and a HF medium, respectively, and were characterized by various methods such as XRD, SEM, pyridine-FT-IR, NH 3 -TPD, 29 Si MAS-NMR. The morphologies of the SAPO-11 molecular sieves obtained from the conventional aqueous medium and the two liquid-phase media exhibit pseudo-spherical aggregates ranging from 7 to 10 μm assembled from cubic plate microcrystallites, whereas the SAPO-11 molecular sieves synthesized from the HF medium exhibit hexagonal prismatic aggregates of about 1–3 μm length. The synthesis media used highly influenced the number and the strength of SAPO-11 acid sites. Compared to SAPO-11 obtained from conventional aqueous medium, SAPO-11 prepared from two-liquid phase media possessed a similar number of BrOnsted acid sites but a much larger number of Lewis acid sites, whereas the SAPO-11 synthesized from HF medium had a similar number of Lewis acid sites but a much lower number of BrOnsted acid sites. The 29 Si MAS-NMR spectra showed that the HF could change the manner of Si incorporation into the SAPO-11 framework. The hydroisomerization of n -hexadecane on Pt/SAPO-11 samples showed that Pt/SAPO-11 obtained from the two-liquid phase media had the largest yield of isomers. The conversion activity of n- hexadecane was dependent on the amount of BrOnsted acid of SAPO-11 molecular sieves, while its hydrocracking activity was related to the strong acid sites of SAPO-11.

Concentration of K-feldspar from a pegmatitic feldspar ore by flotation

Abundant reserves of Na-feldspar (albite) and K-feldspar (orthoclase or microcline) are found in granites, syenite, tracite and pegmatites. As both feldspar minerals have similar chemical structure and physicochemical properties, their separation is challenging. Flotation is known to be the only technique to enable their separation. The fundamentals on the separation of these minerals were well documented in our earlier studies. In this study, a pegmatite ore with a K 2O/Na 2O (3.78:3.37) ratio of 1.12 was studied in a Denver flotation cell both at natural and acidic pH using HF and H 2SO 4. Because of the perthitic structure of the ore no significant separation is observed at natural pH. Interestingly, a selective separation was achieved at low pH using HF and H 2SO 4 (pH 2.5–2.8). The selectivity is induced by the addition of Na + ions through depression of albite. Selective separation has been carried out by stagewise flotation using the tree technique. Accordingly, a pegmatite ore composed of 3.37% Na 2O and 3.78% K 2O is upgraded to 10.51% K 2O and 3.02% Na 2O with a K 2O/Na 2O = 3.48 in HF medium and to 2.55 in H 2SO 4 medium. It is shown that products recovered in other stages are also considered as commercially significant. Especially, quartz, which is recovered in the tailings in HF medium, is suitable for glass industry. The overall results show that commercial utilization of these results is possible.

Prostate specific membrane antigen (PSMA) expression gives prostate cancer cells a growth advantage in a physiologically relevant folate environment in vitro

Prostate specific membrane antigen (PSMA) expression is correlated with stage and grade of prostate cancer suggesting that it confers a growth advantage. We studied if PSMA folate hydrolase activity provides cells a growth advantage in a low folate (LF) micro-environment by hydrolyzing extracellular poly-gamma-glutamated folate to a form that cells can import. Proliferation of LNCaP and DU-145 cells was assessed in media containing low (LF), physiological (PF), or high (HF) folate with or without penta-gamma-glutamated folate and a PSMA specific folate hydrolase inhibitor, 2-(phosphonomethyl)-pentanedioic acid (2-PMPA). LNCaP cells, which express PSMA, and DU-145 cells, which do not, displayed decreased proliferation when grown in LF or PF compared to HF media. This reduction in proliferation was eliminated in LNCaP cells when penta-gamma-glutamated folate was added to the media. In the presence of penta-gamma-glutamated folic acid DU-145 cells displayed increased growth but this was still significantly lower than growth in HF medium. Addition of 2-PMPA attenuated the increased growth seen in LNCaP cells but had no effect on DU-145 cell growth. The folate hydrolase activity of PSMA may provide a growth advantage in LF and PF environments.

First Structural Characterization of a Protactinium(V) Single Oxo Bond in Aqueous Media

The present work describes the first structural studies of protactinium(V) in sulfuric and hydrofluoric acid media using X-ray absorption spectroscopy. The results show unambiguously the absence of the trans-dioxo bond that characterizes the other early actinide elements such as U and Np. In concentrated sulfuric acid (13 M), Pa(V) is proved to exhibit a single oxo bond as postulated in the literature for species in more dilute media. In a 0.5 M HF medium, XANES and EXAFS spectra indicate the absence of any oxo bond: Pa(V) exists in the form of a pure fluoro complex.

The Isobutylene−Isobutane Alkylation Process in Liquid HF Revisited

Details on the mechanism of HF catalyzed isobutylene-isobutane alkylation were investigated. On the basis of available experimental data and high-level quantum chemical calculations, a detailed reaction mechanism is proposed taking into account solvation effects of the medium. On the basis of our computational results, we explain why the density of the liquid media and stirring rates are the most important parameters to achieve maximum yield of alkylate, in agreement with experimental findings. The ab initio Car-Parrinello molecular dynamics calculations show that isobutylene is irreversibly protonated in the liquid HF medium at higher densities, leading to the ion pair formation, which is shown to be a minimum on the potential energy surface after optimization using periodic boundary conditions. The HF medium solvates preferentially the fluoride anion, which is found as solvated [FHF](-) or solvated F(-.)(HF)(3). On the other hand, the tert-butyl cation is weakly solvated, where the closest HF molecules appear at a distance of about 2.9 Angstrom with the fluorine termination of an HF chain.

Transformation of ipecac (Cephaelis ipecacuanha) with Agrobacterium rhizogenes.

Transformed root cultures of ipecac (Cephaelis ipecacuanha A. Richard), one of the recalcitrant woody plant species for Agrobacterium-mediated transformation, were established by co-culturing of in vitro petiole segments with Agrobacterium rhizogenes ATCC 15 834. Southern blot analysis of the established roots revealed that only the TL-DNA was integrated into the plant genome without incorporation of the TR-DNA. The transformed roots grew slowly on phytohormone-free solid medium and adventitious shoots were regenerated after over 6 months of culture on HF, half-strength Murashige and Skoog (1/2 MS) medium in the dark. The individually separated transformed shoots developed into plantlets on phytohormone-free solid medium at 25 degrees C under 16 h/day light, and the plants demonstrated wider leaves, shorter internodes and vigorous root growth compared to non-transformed plants. Effects of basal media and auxins on the growth and the ipecac alkaloid production of the transformed roots were investigated either under light or in the dark. The roots cultured in the dark grew well in Gamborg B5 (B5) liquid medium containing 0.5 mg/L IBA and yielded 112 mg/L of cephaeline and 14 mg/L emetine after 8 weeks of culture.

Differential separation of albite from microcline by monovalent salts in HF medium

Na-feldspar (albite) and K-feldspar (microcline or orthoclase) are major feldspar minerals with identical crystal structures and physico-chemical properties. Flotation appears to be a unique method of separating these minerals. Fundamental studies on an amine/feldspar system in the presence of monovalent salts have shown that separation of these feldspar minerals by flotation is possible at certain a concentration of monovalent salts at natural pH. In this study, flotation separation in hydrofluoric acid (HF) medium in the presence of salt was found to occur at higher amine concentrations at natural pH. A general mechanism based on differences in the charge of albite and microcline is proposed to be responsible for creating a surface charge on albite and microcline onto which amine adsorbs.

Trace element analysis of high purity arsenic through vapour phase dissolution and ICP-QMS

Vapour phase dissolution (VPD) has been used for the dissolution of high purity arsenic through acid vapours generated by aquaregia mixture, prior to trace element characterization. Trace impurities in As were determined by employing ion-exchange and volatilization methodologies for quantitative separation of the As matrix. After dissolving the As matrix through VPD procedure, sample solution in 0.1 M HF medium was loaded on Dowex-50WX8. The sorbed elements were then eluted first with a 20 ml aliquot of 4 M HNO 3 followed by another 10 ml of 6 M HNO 3 for the elution of REE (La, Ce, Gd and Lu). In the volatilization procedure, arsenic was removed from H 2SO 4 medium as volatile bromide by three successive additions of HBr at a temperature of about 220 °C. The trace element determinations were carried out by ICP-QMS. In both the matrix separation procedures namely on Dowex-50WX8 in 0.1 M HF medium and volatilization from H 2SO 4+HBr medium showed that the removal of arsenic matrix was nearly quantitative (>99.99%). The recoveries of trace elements were found to be >95%. Good agreement was obtained for many elements in both the procedures. The VPD approach provides considerable reduction of the process blank levels for all the elements when compared with conventional open dissolution approach. The subsequent ion-exchange or volatilization steps, contribute more to the overall process blanks.