Direct analysis of bromine and iodine in dried serum spots by laser ablation inductively coupled plasma mass spectrometry.

RATIONALE: Accurate quantitative analysis of bromine and iodine in serum is an important aspect of monitoring body condition, but the volatile loss of halogen in sample pretreatment is a troublesome problem. We present a validated and flexible high-throughput method for quantification of bromine and iodine in dried serum spots (DSS) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and an external aqueous standard calibration curve. The influence of serum matrix and laser ablation (LA) conditions on the analysis of bromine and iodine in DSS was researched systematically. METHODS: Aqueous standards without matrix matching were used for calibration to analyze bromine and iodine in serum by LA-ICP-MS. 5-µL volumes of the aqueous standard solution and serum samples in 10 times diluted concentration were deposited on the PTFE paper to form dried standard calibration spots (DSCS) and DSS, of less than 2 mm in diameter. LA was performed using a focused Nd:YAG laser beam in raster lineal scan mode. RESULTS: The limits of detection (LODs) for bromine and iodine in DSS were 0.23 and 0.03 mg L-1 , respectively. The relative standard deviation (RSD) for this method was less than 10%. The samples were also detected with matrix matching calibration by ICP-MS. The accuracy of the method was verified by statistical analysis of these results from ICP-MS and LA-ICP-MS. The accuracy is satisfactory with recoveries ranging from 81.5% to 118%. CONCLUSIONS: A novel and simple approach for high-throughput screening of bromine and iodine in DSS has been established by LA-ICP-MS. Calibration could be achieved using an aqueous standard solution instead of a matrix-matching solution. The method allowed analysis of low-volume biological samples without derivatization and decreased the risk of contamination or loss.

Adsorption of hexavalent chromium using modified walnut shell from solution.

Modified walnut shell (MWS) was obtained using diethylenetriamine through a grafting reaction and its adsorption capacity toward Cr(VI) was enhanced. The adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and elemental analysis and the results showed that the modification was effective. To optimize experimental conditions, the effect of temperature, solution pH, salinity, contact time, and Cr(VI) concentration on adsorption quantity were performed in batch mode. It showed that the adsorption ability for Cr(VI) onto MWH can reach 50.1 mg·g-1 at 303 K with solution pH 3. Both the solution pH and salinity had a great impact on the adsorption capacity. The Langmuir model can predict the equilibrium process while the pseudo-second-order model can describe the kinetic process. The Yan model can be used to predict the column process. Additionally, there was also some regeneration ability for Cr-loaded MWH. Consequently, MWS is effective for removing Cr(VI) from solution.

Facile fabrication of semi-IPN hydrogel adsorbent based on quaternary cellulose via amino-anhydride click reaction in water.

Clean and safe water resources play a key role in environmental safety and human health. Recently, hydrogels have attracted extensive attention due to their non-toxicity, controllable performance, and high adsorption. Herein, a semi- interpenetrating network hydrogel (semi-IPN-Gel) adsorbent based on quaternary cellulose (QC) was prepared by the amino-anhydride click reaction between maleic anhydride copolymer and polyacrylamine hydrochloride (PAH), and its adsorption properties for Eosin Y were studied. First, a binary copolymer (PAM) of acrylamide and maleic anhydride was synthesized by free radical polymerization. Then, the PAM, QC and PAH were dissolved in water, and the pH of the solution was adjusted to alkaline. Semi-IPN-Gel was successfully prepared by fast anhydride-amino click reaction. The preparation conditions of hydrogels were optimized by single-factor experiments. Finally, taking Eosin Y as a model pollutant, the adsorption performance of Eosin Y was studied. The factors influencing the adsorption capacity of the absorbents such as initial concentration of the Eosin Y, temperature, the amount of absorbent, ionic strength and pH of the Eosin Y solutions were investigated. And adsorption data were analyzed via the kinetic model and the isothermal model, indicating that the adsorption process of the hydrogel is a single layer chemisorption process.

Performance-Based Fault Detection and Fault-Tolerant Control for Nonlinear Systems With T-S Fuzzy Implementation.

This article addresses the performance-based fault detection (FD) and fault-tolerant control (FTC) issues for nonlinear systems. For this purpose, in the first part of this article, the performance-based FD and FTC scheme is investigated with the aid of the nonlinear factorization technique. To be specific, the controller parameterization for nonlinear systems is first discussed. The so-called fault-tolerant margin is introduced as an indicator of the system fault-tolerant ability. Then, the FD scheme aiming at estimating and detecting the stability performance degradation of the closed-loop system caused by the system faults is developed. Furthermore, to recover the system performance, the performance-based FTC strategy is presented. In the second part of this article, the design approach of the performance-based FD and FTC scheme is studied by applying the Takagi-Sugeno fuzzy dynamic modeling technique. The achieved results are demonstrated in the end by a case study on the three-tank system.

Urinary metal and metalloid biomarker study of Henoch-Schonlein purpura nephritis using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry.

To obtain a better understanding as to whether concentration alterations of metals and metalloids in urine were related to Henoch-Schonlein purpura nephritis (HSPN), the profiles of as many as 29 elements in urine were compared among three groups, the Henoch-Schonlein purpura (HSP), HSPN and a healthy control group. To this end, a reliable method has been developed for the simultaneous quantification of multiple elements including Li, Be, B, Al, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Cs, Ba, Tl, Pb and Bi in urine using inductively coupled plasma orthogonal acceleration time-of-flight mass spectrometry (ICP-oa-TOF-MS). The process of sample pre-treatment used a direct 20-fold dilution method with centrifuged urine. The internal standard element used for quantification was 103Rh, and 1,4-butanediol was chosen as a matrix matching reagent. The method detection limits of these 29 elements were in the range of 0.04-12ngmL-1. Results of statistical analysis revealed that the concentrations of 15 elements and the element homeostasis were significantly different among these three groups. Our study provides a potential method for HSPN metal and metalloid biomarker discovery.

[Determination of trace palladium in medicament by electric-heated AAS with molybdenum-coated graphite tube].

This paper reports a new method for the determination of palladium in exported medicament doxycycline hydrochloride by graphite furnace atomic absorption spectrometry. The optimum conditions for the determination of trace Pd were investigated in details. When the graphite tube was coated with molybdenum, the sensitivity was enhanced and when EDTA was used as the matrix modifier the matrix interference was eliminated efficiently. The result indicates that the detection limit for Pd is 4.6 x 10(-10) g and the relative standard deviation is 4.3%. The method is accurate and rapid and can be used successfully to determine actual samples. The recovery rate of palladium is in the range of 97.1% to 103.3%.

[Determination of trace barium in environmental samples by electric-heated AAS with lanthanum-coated graphite tube].

In this paper a new method was established for determination of trace barium in environmental samples by graphite furnace atomic absorption spectrometry. In the presence of matrix modifier magnesium nitrate, the matrix inference was eliminated efficiently. To avoid producing barium carbide, the graphite tubes were coated differently with lanthanum, zirconium, tungsten, molybdenum, and tantalum. Results showed that the tube with lanthanum was the best. The atomization temperature was diminished. The sensitivity was improved, and the tube with lanthanum gave the longest service life. So we used the tube to determine trace barium. The trace barium in Geodchemical Standard Reference Sample Soil-1 (GSS-1) was determined by the new method, the test results showed that the method was reliability and accurate. The method has been used for the determination of trace barium in environmental samples and in water of Yellow River. The detection limit for Ba was 2.1 x 10(-12) g and the relative standard deviation(RSD) was 5.4% for 15 ng.mL-1 Ba.

Polymeric zinc ferrocenyl sulfonate as a molecular aspirator for the removal of toxic metal ions.

A porous bilayered open coordination polymer [Zn(4,4'-bpy)(2)(FcphSO(3))(2)](n) (1; FcphSO(3)Na=m-ferrocenyl benzenesulfonate), has been assembled from Zn(NO(3))(2), m-ferrocenyl benzenesulfonate, and the bridging ligand 4,4'-bipyridine (4,4'-bpy). Ion-exchange induced products [Cd(0.6)Zn(0.4)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (2), [Zn(0.75)Pb(0.25)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (3), and [Cu(0.5)Zn(0.5)(4,4'-bpy)(2)(FcphSO(3))(2)](n) (4) could be obtained directly by suspending a big single crystal of 1 into concentrated solutions of Cd(NO(3))(2), Pb(NO(3))(2), and Cu(NO(3))(2), respectively. Most importantly, the big single crystal of 1 could be partly regenerated after immersion into concentrated aqueous solutions of Zn(NO(3))(2). On the other hand, powdered 1 could also be used as a metal ion adsorbent because of the well-defined pore size and pore shape. Ion exchange takes place along with the process of ion sorption. The big single crystal of 1 removes harmful metal ions by means of ion exchange, whereas powdered 1 removes toxic metal ions mainly through ion sorption. Also, compound 1 could be employed as a multi-ion analysis fluorescent probe to detect dangerous metal ions, such as Pb(2+), Cd(2+), Ag(+), and Cu(2+). The compounds described in this study may have potential applications in the design of new molecular devices.

Highly selective ferric ion sorption and exchange by crystalline metal phosphonates constructed from tetraphosphonic acids.

With the motivation of searching for highly selective ferric ion sorbents, two open-framework and microporous materials, {[Pb7(HEDTP)2(H2O)] x 7H2O}n (1) and {[Zn2(H4EDTP)] x 2H2O}n (2) [H8EDTP = N,N,N',N'-ethylenediaminetetrakis(methylenephosphonic acid)], have been synthesized and structurally characterized. The structure of compound 1 results from the seven crystallographically different lead atoms that are bridged by two HEDTP(7-) ligands to yield a three-dimensional microporous framework with tunnels along the a and b axes. Compound 2 features a layer architecture built of square waves along the a axis. The layers are connected by hydrogen bonds between uncoordinated phosphonate oxygen atoms to form a three-dimensional supramolecular network, with one-dimensional tunnels along the a axis. Both compounds 1 and 2 exhibited high ion sorption and exchange capacities for millimolar concentrations of Fe(III). Specifically, when 0.01 g of 1 (or 2) was added to 5 mL of a 1 mM metallic chloride aqueous solution and the mixture was allowed to stand for 2 days at room temperature, compound 1 adsorbed nearly 100% of Fe(III) and compound 2 adsorbed 96.8% of Fe(III). They were also found to adsorb ferric ions selectively over other metal ions, such as Ca(II), Cr(II), Mn(II), Cu(II), Zn(II), Cd(II), etc. Their special ferric ion uptake capacities may be attributed to the cation exchange, coordination bonding, and electrostatic attraction between ferric ions and metal phosphonates.

A series of metal-organic polymers assembled from MCl2 (M = Zn, Cd, Co, Cu): structures, third-order nonlinear optical and fluorescent properties.

In this paper four metal-organic polymers {[Zn(fcz)Cl2].CH3OH}n 1, {[Cd(fcz)2Cl2].CH3OH.2H2O}n 2, {[Co(fcz)2Cl2].2CH3OH}n 3 and {[Cu(fcz)2Cl2].2CH3OH}n 4 (fcz = fluconazole: alpha-(2,4-difluorophenyl)-alpha-(1H-1,2,4-triazol-l-ylmethyl)-1H-1,2,4-triazole-l-ethanol) were synthesized and characterized by X-ray single crystal diffraction. Polymer consists of 1-D infinite chains arranged along the b-axis. All of polymers 2-4 exhibit a 2-D rhombohedral grid structure. We study the third-order nonlinear optical properties of fcz and polymers 1-4 in DMF solution by using 8 ns laser pulses at 532 nm, and find that 1 and 4 exhibit different NLO properties from fcz and both 2 and 3 show similar NLO properties to fcz. 1 possesses strong NLO refractive effects and large NLO absorptive behaviors. 2, 3 and fcz exhibit strong refractive effects, but their NLO absorptive behaviors are weaker than that of 1. The NLO effects of 4 are very weak. The study of optical limiting (OL) effects by using 40 ps laser pulses at 532 nm shows that fcz and polymer 3 possess a strong OL effect. The optical limiting threshold values of 0.15 J cm(-2) for fcz and 0.16 J cm(-2) for are comparable to those of many heterothiometallate clusters. Polymers 1, 2 and 4 show a weak OL effect. The fluorescent spectra in DMF solution (concentration: 1 x 10(-4) mol dm(-3)) show that polymers 1-4 exhibit different luminescence properties from fcz. The maximum wavelength of polymers 1-3 are blue shifted gradually by 2-12 nm while polymer 4 exhibits a fluorescent self-quenching phenomenon. These results demonstrate that metal ions play an important part in the NLO and fluorescent properties of coordination polymers.

Hydrothermal syntheses, crystal structures, and characteristics of a series of Cd-btx coordination polymers (btx = 1,4-Bis(triazol-1-ylmethyl)benzene).

Four novel cadmium-btx (btx = 1,4-bis(triazol-1-ylmethyl)benzene) coordination polymers [Cd(btx)(2)(NO(3))(2)](n)(1), [Cd(btx)(2)Cl(2)](n)(2), [Cd(btx)(SO(4))(H(2)O)(2)](n)(3), and [Cd(btx)(S(2)O(7))(H(2)O)](n)(4) have been prepared by hydrothermal reaction (140 or 180 degrees C) and characterized. Both 1 and 2 have two-dimensional rhombohedral grid structures, 3 possesses a two-dimensional rectangular grid structure, and 4 displays a three-dimensional framework, which is formed by btx bridging parallel layers. To the author's best knowledge, polymer 4 is the first Cd(II) polymer in which the Cd(II) ion is eight-coordinated in a hexagonal bipyrimidal geometry. In addition, we studied the effects of temperature on the hydrothermal reaction system of btx and CdSO(4) and found that different products can be obtained at different temperatures. Furthermore, polymer 3 possesses a very strong third-order NLO absorptive effect with an alpha(2) value of 1.15 x 10(-)(9) m W(-1). Polymers 2-4 display strong fluorescent emissions in the solid state at room temperature. The DTA and TGA results of the four polymers are in agreement with the crystal structures.