Real Sample Solutions Research Articles

Synthesis and Efficiency of Poly(Acryl- p -Nitrophenylamidrazone- p -Nitrophenylhydrazide) Chelating Fibre for Pre-Concentration and Separation of Trace Concentrations of Bi 3+ , In 3+ , Sn 4+ , Ga 3+ and Ti 4+

A new poly(acryl-p-nitrophenylamidrazone-p-nitrophenylhydrazide) chelating fibre was synthesized from polyacrylnitrile fibre, and the structure of the chelating fibre was determined with the help of the FT-IR spectrum. The parameters influencing the efficiency of the fibre for concentrating trace amounts of Bi3+, In3+, Sn4+, Ga3+ and Ti4+, including sample acidity during enrichment, flow rate, adsorptive capacity, re-usability, interfering ions and desorption conditions were investigated. Trace Bi3+, In3+, Sn4+, Ga3+ and Ti4+ were enriched and separated from real sample solutions and detected using inductively coupled plasma optical emission spectrometry (ICP-OES) with satisfactory results. The experiments show that the method is rapid, precise, simple and convenient to use.

New chromatographic method for separation and determination of denatured α s1-, α s2-, β- and κ-caseins by hydrophobic interaction chromatography

Separation and determination of denatured α-, β- and κ-caseins by hydrophobic interaction chromatography (HIC) was improved by using a TSK-Gel Ether-5PW column (Tosoh Biosep). The method, already proposed and performed by a TSK-Gel Phenyl-5PW column (Tosoh Biosep), is based on fast and easy solubilization of commercial and real samples by 4.0 M guanidine thiocyanate and HIC analysis in the presence of 8.0 M urea in the mobile phase. Employment of the less hydrophobic ether phase had the main advantage of separating casein fractions in less than 22 min and, additionally, of separating α-casein in α s1- and α s2-casein fractions. The method has been validated by the analysis of reference skim milk powder (BCR-063R) certified for total nitrogen content. A linear relationship between the concentration of casein and peak area (UV absorbance detector at 280 nm) has been obtained over the concentration range of 0.5–40 μ M. The detection limit for α-, β- and κ-caseins ranged between 0.33 and 0.65 μ M. The precision of the method was evaluated, the RSDs for α s1-, α s2-, β- and κ-casein determination ranging between 2.3 and 5.5% for standard solutions and between 4.4 and 6.2% for real sample solutions. The mean value of casein content found in eight aliquots of BCR-063R calculated with respect to the total protein content (estimated on the basis of certified total nitrogen content) was 78.3±6.1%. Results of linear fitting of standard additions data of α s1-, α s2-, β- and κ-caseins to BCR-063R were compared with linear fitting of α s1-, α s2-, β- and κ-casein calibration data. The method was applied to commercial caseins and to 30 real, raw samples. A statistical comparison was performed between results on quantitation of α-, β- and κ-caseins obtained by TSK-Gel Ether-5PW and TSK-Gel Phenyl-5PW HIC columns, showing more accurate results for chromatographic analysis performed by the ether column.

Efficiency and application of poly(acryldinitrophenylamidrazone-dinitroacrylphenylhydrazine) chelating fiber for pre-concentrating and separating trace Au(III), Ru(III), In(III), Bi(III), Zr(IV), V(V), Ga(III) and Ti(IV) from solution samples

Poly(acryldinitrophenylamidrazone-dinitroacrylphenylhydrazine) chelating fiber was synthesized from polyacrylonitrile fiber and used for enrichment and separation for traces of Au(III), Ru(III), In(III), Bi(III), Zr(IV), V(V), Ga(III) and Ti(IV) ions from solution samples. The acidity, rate, re-use, capacity and interference on the adsorption of ions on the chelating fiber as well as the conditions of desorption of these ions from the chelating fiber were investigated by means of inductively coupled plasma optical emission spectrometry. The results show that 10–100 ng ml −1 of Au(III), Ru(III), In(III), Bi(III), Zr(IV), V(V), Ga(III) and Ti(IV) ions can be quantitatively enriched by the chelating fiber at a 2 ml min −1 of flow rate in the range pH 4–5, and desorbed quantitatively with 20 ml of 5 M HCl for In(III), Bi(III), Zr(IV), V(V), Ga(III), Ti(IV) and 20 ml of 4 M HCl+2% CS(NH 2) 2 solution for Au(III), Ru(III) (with recovery>95%). 50- to 500- fold excesses of Fe(III), Al(III), Mg(II), Mn(II), Ca(II), Cu(II), Ni(II) ions cause little interference in the concentration and determination of analyzed ions. When the fiber was reused for 8 times, the recoveries of the above ions enriched by the fiber were still over 87%. The relative standard deviations (RSDs) for the enrichment and determination of 10 ng ml −1 Au, Ru, In, Bi, Ga and 1 ng ml −1 Zr, V, Ti were lower than 3.0%. The results obtained for these ions in real solution samples by this method were basically in agreement with the given values with average errors of less than 6.3%. FT-IR spectra show that existence of NNCNHNH, OCNHNH and NO 2 functional groups are verified in chelating fiber, and Au(III) or Ru(III) is mainly combined with nitrogen (or oxygen) of the groups to form a chelate complex.

ICP-AES determination of traces of noble metal ions pre-concentrated and separated on a new polyacrylacylaminothiourea chelating fiber.

A new polyacrylacylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber) and aminothiourea. This fiber was used for the pre-concentration and separation of traces of AuIII, PtIV, PdIV, and IrIV ions from aqueous samples. Factors effecting and parameters for the adsorption of these ions onto the resin, such as acidity, rate, reuse, capacity, and interference of other ions, were investigated using inductively-coupled plasma atomic emission spectrometry (ICP-AES). Conditions of desorption of these ions from the resin were similarly investigated. The enrichment factor was 100. The relative standard deviation for the determination of AuIII, PtIV, PdIV, and IrIV were in the range of 0.7-3.0% for 20.0 ng/mL of each. The recoveries of a standard from real solution samples were between 96% and 100%. The concentrations of analyzed ions in a digested metal powder sample processed with the method proposed were in good agreement with the certified values.

Synthesis of polyacrylaminoimidazole chelating fiber and properties of concentration and separation of trace Au, Hg and Pd from samples

A novel polyacrylaminoimidazole chelating fiber is synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber) and used for the preconcentration and separation of trace Au(III), Hg(II) and Pd(IV) ions from solution samples. The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 15.0 ml min −1 at pH 3 and can also be desorbed with 15 ml of 4 M HCl+3% thiourea from the fiber column, with recoveries of 96.5–100%. The chelating fiber is reused ten times; the recoveries of these ions are still over 92%, and 100–1000 times of excess of Fe(III), Al(III), Ca(II), Mg(II), Ni(II), Mn(II), Cu(II), Zn(II) and Cd(II) causes no interference in the determination of these ions by inductively coupled plasma atomic emission spectrometry. The capacities of the fiber for the analytes are in the range of 1.56–2.92 mmol g −1. The results show that the relative standard deviations for the determination of 50.0 ng ml −1 each of Au(III), Hg(IV) and Pd(IV) are in the range of 0.7–2.1%. The recoveries of a standard added in real solution samples are between 97 and 99%, and the concentration of each ion in powder sample detected by the method is in good agreement with the certified value.

Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

AbstractA novel polyacrylaminothiourea chelating fiber was synthesized simply and rapidly from nitrilon (an acrylonitrile‐based synthetic fiber), which was applied to preconcentrate and separate of trace amount of Au(III), Pt(IV), Pd(IV) and Ir (IV) ions from solution of samples. The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0 mL/min at pH2, and can also be desorbed with 15 mL of 4 mol/L HCl + 3% thiourea from the fiber column with recoveries of 96.5%‐100%. The chelating fiber can be reused for ten times, the recoveries of these ions are still over 92%, and hundred to thousand times of excess of Fe(III), Al(III), Ca(II), Mg(II), Ni(II), Mn(II), Cu(II), Zn(II), and Cd (II) cause no interference on the determination of the analyzed ions by inductively‐coupled plasma atomic emission spectrometry (ICP‐AES). The static saturation adsorption capacities of the fiber for the analytes are in the range of 1.15‐2.80 mmol/g. The relative standard deviations for the determination of 20.0 ng/mL each of Au(III), Pt(IV), Pd(IV) and Ir (IV) are in the range of 0.7%‐3.0%. The recoveries for test from standard additions to real solution samples are between 96% and 100%. The concentration of each ion in powder sample detected by the method is in good agreement with the certified value.

Synthesis and Applications of Poly(Acrylphenylamidrazone-Phenyl-Hydrazide-Acylphenylhydrazine) Chelating Fiber for Preconcentration and Separation of Trae In(III), Zr(IV), Tl(I), V(V), Ga(III) and Ti(IV) from Solution Samples

An ICP-OES method using a new poly (acrylphenylamidrazone-phenylhydrazide-acylphenylhydrazine) chelating fiber to preconcentrate and separate trace In(III), Zr(IV), Tl(I), V(V), Ga(III) and Ti(IV) ions from solution samples has been established. The new chelating fiber was synthesized using polyacrylonitrile fiber as a starting material and the structure of the chelating fiber was determined by FT infrared spectrometry. The acidity, adsorption rate, re-use, capacity and interference on the adsorption of ions on the chelating fiber as well as the conditions of desorption of these ions from the chelating fiber were investigated by means of inductively coupled plasma optical emission spectrometry (ICP-OES). The results show that the relative standard deviations for the determination of 10 ng/ml In, Tl, Ga and 1 ng/ml Zr, V, Ti were lower than 2.5%. The results obtained for these ions in real solution samples by this method were basically in agreement with the given values with average errors of less than 4%.

Efficiency and mechanism of new poly(acryl-phenylamidrazone phenylhydrazide) chelating fiber for adsorbing trace Ga, In, Bi, V and Ti from solution

A new po1y(acrylphenylamidrazone phenylhydrazide) chelating fiber is synthesized from polyacrylonitrile fiber and used for preconcentration and separation of trace Ga(III), In(III), Bi(III), V(V) and Ti(IV) from solution (5–50 ng ml −1 Ti(IV) or V(V) and 50–500 ng ml −1 Ga(III), In (III) or Bi(III) in 1000–100 ml of solution can be enriched quantitatively by 0.15 g of fiber at a 4 ml min −1 flow rate in the pH range 5–7 with recoveries >95%). These ions can be desorbed quantitatively with 20 ml of 4 M hydrochloric acid at 2 ml min −1 from the fiber column. When the fiber which had been treated with concentrated hydrochloric acid and washed with distilled water until neutral was reused eight times, the recoveries of the above ions by enrichment were still >95%. Two-hundred-fold to 10 000-fold excesses of Cu(II), Zn(II), Ca(II), Mn(II), Cr(III), Fe(III), Ba(II) and Al(III) caused little interference in the determination of these ions by inductively coupled plasma-atomic emission spectrometers (ICP-AES). The relative standard deviations for enrichment and determination of 50 ng ml −1 Ga, In or Bi and 10 ng ml −1 V or Ti are in the range 1.2–2.7%. The contents of these ions in real solution samples determined by this method were in agreement with the certified values of the samples with average errors <3.7%.

Separation and determination of denatured caseins by hydrophobic interaction chromatography Part II. Method validation and applications.

A method recently described for the separation of denatured alpha-, beta- and kappa-caseins by hydrophobic interaction chromatography was validated by the analysis of reference skim milk powder (BCR-063R) certificated for total nitrogen content. The method is based on fast and easy solubilization of commercial and real samples by 4.0 M guanidine thiocyanate and elution on a TSK-Gel Phenyl-5PW column (TosoHaas) in the presence of 8.0 M urea in the mobile phase. No preliminary precipitation or separation of the casein fraction is required. A linear relationship between the concentration of casein and peak area (UV absorbance detector at 280 nm) was obtained over the concentration range 0.5-60 microM. The detection limits for alpha-, beta- and kappa-caseins ranged between 0.30 and 0.65 microM. The precision of the method was evaluated; the relative standard deviation for alpha-, beta- and kappa-casein determination ranged between 2.2 and 2.7% for standard solutions and between 3.5 and 6.2% for real sample solutions. The mean casein content found in 10 aliquots of BCR-063R calculated with respect to the total protein content (estimated on the basis of certified total nitrogen content) was 79.1+/-2.7%. Results of linear fitting of standard additions data for alpha-, beta- and kappa-caseins to BCR-063R were compared with linear fitting of alpha-, beta- and kappa-casein calibration data. The method was applied to commercial caseins and to 31 real, raw samples [processed cow's milk (pasteurised, UHT-treated), follow-up milk powders, cream, cheeses, casein-free infant formulae, cookies for babies containing milk proteins] with the aim of showing the wide applicability of the method in order to determine alpha-, beta- and kappa-caseins.

Synthesis of polyacrylacylaminourea chelating fiber and properties of concentration and separation of trace metal ions from samples

A novel polyacrylacylaminourea chelating fiber is synthesized simply and rapidly from nitrilon (an acrylonitrile-based synthetic fiber) and used for the preconcentration and separation of trace In(III), Bi(III), Cr(III), V(V) and Ti(IV) ions from solution samples. The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 10.0 ml min −1 at pH 3, and can also be desorbed with 10 ml of 2 M HCl+2% thiourea from the fiber column with recoveries of 97–99%. The chelating fiber is reused for eight times, the recoveries of these ions are still over 92%, and 100–1000 times of excess of Fe(III), Al(III), Ca(II), Mg(II), Ni(II), Mn(II), Cu(II), Zn(II), and Cd(II) cause no interference in the determination of these ions by inductively-coupled plasma atomic emission spectrometry. The capacities of the fiber for the analytes are in the 0.23–1.17 mmol g −1 range. The results show the relative standard deviation for the determination of 50.0 ng ml −1 In(III) and Bi(III), 5.0 ng ml −1 Cr(III), V(V) and Ti(IV) are in the 0.5–3.2% range. The recoveries of a standard added in real solution samples are between 96 and 100%, and the concentration of each ion in mineral sample detected by the method is in good agreement with the certified value.

Synthesis of spherical macroporous epoxy-dicyandiamide chelating resin and properties of concentration and separation of trace metal ions from samples

A novel spherical macroporous epoxy-dicyandiamide chelating resin is synthesized simply and rapidly from epoxy resin and use for the preconcentration and separation of trace Ga(III), In(III), Bi(III), Sn(IV), Pb(II), V(V) and Ti(IV) ions from solution samples. The analyzed ions can be quantitatively concentrated by the resin at flow rate of 3.0 ml min −1 at pH 3, and can also be desorbed with 10 ml of 4 M HCl+0.2 g thiourea from the resin column with recoveries of 97–100%. The chelating resin is reused for eight times, the recoveries of these ions are still over 92%, and a 100–1000 times of excess of Fe(III ), Al(III),Ca(II), Mg(III), Ni(II), Mn(II), Co(II), Cu(II), Zn(II), and Cd(II) cause no interference in the determination of these ions by inductively-coupled plasma atomic emission spectrometry. The capacities of the resin for the analytes are in the range of 0.66–4.20 mmol g −1. The results show the relative standard deviation for the determination of 50.0 ng ml −1 Ga(III), In(III), Bi(III), Sn(IV) and Pb(II), 5.0 ng ml −1 V(V) and Ti(IV) are in the range of 1.2–4.0%. The recoveries of a standard added in real solution samples are between 96 and 100%, and the concentration of each ion in mineral sample detected by the method is in good agreement with the certified value.

ICP-OES determination of traces of Ru, Au, V and Ti preconcentrated and separated by a new poly(epoxy-melamine) chelating resin from solutions

A new poly(epoxy-melamine) chelating resin is synthesized from epoxy resin and used for the preconcentration and separation of traces of Ru(III), Au(III), V(V) and Ti(IV) ions from sample solutions. The ions analyzed can be quantitatively enriched by the resin at a flow-rate of 2 mL/min at pH 4, and quantitatively desorbed with 10 mL of 1 mol/L HCl + 0.2 g CS(NH2)2 at a flow-rate of 1 mL/min with recoveries of over 97%. The chelating resin can be reused 7 times without obvious loss of efficiency. Thousand-fold excesses of coexistent ions caused little interference during the enrichment and determination steps. The RSDs for the determination of 50 ng/mL Ru(III) and Au(III), 5.0 ng/mL V(V) and Ti(IV) were in the range of 1.5–4.5%. The recoveries of added standards in a real sample solution are between 96% and 100%, and the results for the ions analyzed in a nickel alloy sample are in good agreement with their reported values.

Assessment of the content of selected trace elements in serum of term and pre-term newborns by inductively coupled plasma mass spectrometry

A method for the determination of 14 trace and ultra-trace elements (Al, Cd, Co, Cu, Li, Mn, Mo, Ni, Pb, Pt, Rb, Sb, Se and Zn) in serum of newborns by inductively coupled plasma mass spectrometry (ICP-MS) with ultrasonic nebulization is described. Cord blood samples were collected from term and pre-term newborns by means of a teflon catheter within 24 h from delivery. The eligibility criteria adopted in this study require that only “normal” (i.e. fully representative of their specific conditions) subjects be selected for blood collection. From this standpoint, pre-term newborns suffering only from diseases derived from their status, i.e. really representative of the group under investigation, were included in the study. After centrifugation, serum aliquots were stored in metal-free plastic test tubes at −20 °C until analysis. Sample treatment was kept to a minimum, i.e. serum samples were diluted 20–50-fold with 0.14 M HNO 3 and spiked with suitable amounts of Rh and Tl, the internal standards, to account for nebulization effects and for instability of nebulization and ionization. To minimize the effects of matrix interferences, blanks and calibrants were prepared from synthetic solution containing the same major components as the real sample solutions. The analytical method adopted, i.e. ICP-MS determination combined with ultrasonic nebulization, turned out to be fully suited to the aim of this study. Experimental data were statistically analyzed by parametric and non-parametric tests in order to assess tentative reference ranges of elemental concentrations. To this end, newborns were grouped by gestational age and body weight at the delivery. Results allow tentative reference values to be assessed for the above-mentioned elements in serum of newborns, with the only exception of Pt, which was below the detection power of the technique.

ICP-OES Determination of Trace Ga,In,Bi,Sn and Pb Preconcentrated by Macroporous Poly(Vinylethylenediamine) Chelating Resin1

Abstract An ICP-OES method for applying a macroporous ploy(vinylethy-lenediamine) chelating resin to preconcentrate and separate trace Ga(III), In(III), Bi(III), Sn(IV) and Pb(II) ions from solution samples is established. The analyzed ions of 0.05–0.5 ug/ml can be enriched by the resin of 0.07-g amount at a 1.0 ml/min of flow rate at pH 5, and can be also desorbed with a 10 ml of 3 M HClO4 from the resin column, with recoveries over 96%. The chelating resin reused 7 times can still adsorb quantitatively the Ga, In, Bi, Sn and Pb ions, and a 500-fold excess of Fe(III), Al(III), Mn(II), Cu(II), Ni(II), Zn(II) and Cr(III) caused little interference with the enrichment and determination of these ions. The RSDs of the proposed method are in the range 1.2–5.5% for each analyzed ion. The recoveries of added standard in real solution samples are between 94% and 100%, and the concentration of each ion in a mineral sample detected by the method is in good agreement with the analyzed value by ETAAS method. 1The sub...

Flow system based on a binary sampling process for automatic dilutions prior to flame atomic spectrometry

A microcomputer-controlled flow system to perform automatic dilutions exploiting a binary sampling process is proposed. Introduction of precise volumes of sample and solvent was achieved by solenoid valves. The possibility to get different volumetric fractions was realized by software, which defined the time delays of the valves and could be used, e.g., for samples with analyte concentrations exceeding the analytical range. A noteworthy feature is that sample and standards processing is not necessarily the same. The analytical performance was exhaustively investigated, in particular the precision of standard measurements generated after application of different dilutions, or repeatability of results of 20 and 40 times diluted real sample solutions. The feasibility of the approach was demonstrated by the on-line automatic dilution of plant digests for determining Ca and K by flame atomic absorption and emission spectrometry. Precision of measurements performed on a solution produced by the automatic 10-fold dilution of a 100 mg l solution was characterized by a R.S.D. < 1%. Accuracy was assessed by analysing vegetal reference materials after diluting 10 or 20 times. Results were in agreement at 95% significance level with the certified values. Comparison of automatic and manual dilutions by using a paired t-test on a set of samples with varying composition presented no statistical difference at the 95% significance level.

Synthesis and efficiency of a polyacrylacylisothiourea chelating fibre for the preconcentration and separation of trace amounts of gold, palladium and ruthenium from solution samples

A polyacrylacylisothiourea chelating fibre was synthesized using polyacrylonitrile fibre as a starting material, and the structure of the chelating fibre was determined by infrared spectrometry. The parameters influencing the efficiency of the fibre at concentrating trace amounts of AuIII, PdIV, and RuIII, including acidity, flow rate, adsorption capacity, effect of re-use, interfering ions, and desorption, were investigated. Gold(III), PdIV, and RuIII were enriched and separated from real samples and were detected using inductively coupled plasma optical emission spectrometry with satisfactory results. For concentrations of AuIII, PdIV, and RuIII of 0.008 mg l–1, the relative standard deviation was 1.8% for AuIII, 2.5% for PdIV, and 0.8% for RuIII. The concentrations obtained for these ions in real solution samples by this method were basically in agreement with the given values, with average errors of less than 2.5%. The method is rapid, precise, simple, and convenient to use.

Synthesis of poly(acrylamidrazone-hydrazide) chelating fiber and application of enrichment—separation for traces of indium, tin, chromium, vanadium and titanium from solution samples

A poly(acrylamidrazone-hydrazide) chelating fiber has been synthesized from polyacrylonitrile fiber and used for enrichment—separation of traces of In(III), Sn(IV), Cr(III), VO(I) and Ti(IV) from solution samples with satisfactory results. These ions (5–250 ng/ml) can be quantitatively enriched (recovery > 95%) by the fiber at a 10 ml/min flow rate in the pH range 4–7, and desorbed quantitatively (recovery > 95%) with 10 ml of 2–5 M hydrochloric acid from a fiber column at 6 ml/min flow rate. When the fiber, which had been stored in a glass bottle for about two years and then treated with strong acids (concentrated hydrochloric or nitric acid), was reused 10 times, the recoveries of the above ions by enrichment were still over 94%, and hundred-fold to thousand-fold excesses of Cu(II), Zn(II), Co(II), Ca(II), Mg(II), Fe(III) and Al(III) caused little interference in the determination of these ions by ICP—AES. The lowest concentrations for the proposed method were 50 ng/ml and In and Sn and 5 ng/ml for Cr, V and Ti. The RSD was 1.2–4.0%. The contents of these ions in real solution samples determined by this method were basically in agreement with the certified values of the samples, with average errors below 3.3%. The IR spectra of the fiber adsorbed with Cr(III) or VO(I) showed that Cr(III) or VO(I) combined mainly with nitrogen atoms in the fiber to form a coordination complex.

Separation of carbohydrates on a new polar bonded phase material

The separation of a number of carbohydrates on Partisil-10 PAC, a 10-μm silica gel with a permanently bonded polar phase, is described. The basic mobile phase is acetonitrile-water, but various acids or salts may be added to the aqueous portion to change the selectivity of the separation. A study of the effect of H 3PO 4, HCl, HCLO 4, KH 2PO 4, and sodium acetate on the separation of mono-, di-, and trisaccharides is discussed and chromatograms of several real sample solutions are shown.