Determination of Titanium in Nano-Titanium(IV) Oxide Composite Food Packaging by Microwave Digestion and Inductively Coupled Plasma Atomic Emission Spectrometry and Inductively Coupled Plasma Mass Spectrometry

Titanium was determined in nano-titanium(IV) oxide food packaging by microwave digestion with inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Microwave digestion was optimized using different acid combinations. Both spectrometry techniques showed good reproducibility, repeatability, and recovery. For ICP-AES, the limit of detection was 5.0 mg kg^?1, the linear dynamic range was 100–5000 µ g L^?1, the average recoveries for blank samples spiked with titanium were between 94.7% and 100.1%, and the relative standard deviations were from 2.1% to 7.1%. By ICP-MS, the limit of detection was 0.3 mg kg^?1, the linear dynamic range was 0.5–200 µ g L^?1, the recoveries were 88.4%–96.3%, and the relative standard deviations were 6.3%–7.4%. These results indicated that methods were effective for the determination of titanium in food packaging.     

Development of an ICP-MS immunoassay for the detection of anti-erythropoietin antibodies

A sandwich-type immunoassay linked with inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the detection of anti-erythropoietin antibodies (anti-EPO Abs). Recombinant human erythropoietin (rhEPO) was immobilized on the solid phase to capture anti-rhEPO Abs specifically. After the immunoreactions with Au-labeled goat-anti-rabbit IgG, a diluted HNO₃ (2%) was used to dissociate Au nanoparticles which was then introduced to the ICP-MS for measurements. Under the optimized conditions, the calibration graph for anti-EPO Abs was linear in the range of 35.6-500 ng mL⁻¹ with a detection limit of 10.7 ng mL⁻¹ (3σ, n = 9). The relative standard deviation (R.S.D.) for three replicate measurements of 30.9 ng mL⁻¹ of anti-EPO Abs was 8.43%. The recoveries of anti-EPO Abs in sera at the spiking level of 50, 100, 150, 200 and 400 ng mL⁻¹ were 99.2%, 101.5%, 95.0%, 94.0% and 102.9%, respectively. For the real sample analysis, 26 samples from healthy people and 53 samples from patients with rhEPO treatments were studied. One sample from patients showed significantly higher anti-EPO Abs from other samples, indicating a possibility of immune response of this patient.     

Sensitive sandwich immunoassay based on single particle mode inductively coupled plasma mass spectrometry detection

A sensitive sandwich type immunoassay has been proposed with the detection by inductively coupled plasma mass spectrometry (ICP-MS) in a single particle mode (time resolved analysis). The signal induced by the flash of ions (¹⁹⁷Au⁺) due to the ionization of single Au-nanoparticle (Au-NP) label in the plasma torch can be measured by the mass spectrometer. The frequency of the transient signals is proportional to the concentration of Au-NPs labels. Characteristics of the signals obtained from Au-NPs of 20, 45 and 80 nm in diameters were discussed. The analytical figures for the determination of Au-labeled IgG using ICP-MS in conventional integral mode and single particle mode were compared in detail. Rabbit-anti-human IgG was used as a model analyte in the sandwich immunoassay. A detection limit (3σ) of 0.1 ng mL⁻¹ was obtained for rabbit-anti-human IgG after immunoreactions, with a linear range of 0.3-10 ng mL⁻¹ and a RSD of 8.1% (2.0 ng mL⁻¹). Finally, the proposed method was successfully applied to spiked rabbit-anti-human IgG samples and rabbit-anti-human serum samples. The method resulted to be a highly sensitive ICP-MS based sandwich type immunoassay.     

Gold colloid analysis by inductively coupled plasma-mass spectrometry in a single particle mode

Analysis in a single particle mode of gold colloids in water has been performed by inductively coupled plasma-mass spectrometry (ICP-MS). The signal induced by the flash of ions due to the ionization of a colloid in the plasma torch can be measured for the ions ¹⁹⁷Au⁺ by the mass spectrometer without interferences. The intensity of the MS signal is recorded in time scan. The recorded peak distributions were analysed as a function of the colloid size for five monodisperse colloids (80-250 nm). This study describes the experimental conditions to analyse gold colloids in a single particle mode. The size detection limit is around 25 nm corresponding to 0.15 fg colloids and one particle per ml may be detected during a 1 min time scan within standard procedure.     

Extraction of trace amounts of mercury with sodium dodecyle sulphate-coated magnetite nanoparticles and its determination by flow injection inductively coupled plasma-optical emission spectrometry

A new method for solid-phase extraction and preconcentration of trace amounts Hg(II) from environmental samples was developed by using sodium dodecyle sulphate-coated magnetite nanoparticles (SDS-coated Fe₃O₄ NPs) as a new extractant. The procedure is based on the adsorption of the analyte, as mercury-Michler's thioketone [Hg₂(TMK)₄]²⁺ complex on the negatively charged surface of the SDS-coated Fe₃O₄ NPs and then elution of the preconcentrated mercury from the surface of the SDS-coated Fe₃O₄ NPs prior to its determination by flow injection inductively coupled plasma-optical emission spectrometry. The effects of pH, TMK concentration, SDS and Fe₃O₄ NPs amounts, eluent type, sample volume and interfering ions on the recovery of the analyte were investigated. Under optimized conditions, the calibration curve was linear in the range of 0.2-100 ng mL⁻¹ with r² = 0.9994 (n = 8). The limit of detection for Hg(II) determination was 0.04 ng mL⁻¹. Also, relative standard deviation (R.S.D.) for the determination of 2 and 50 ng mL⁻¹ of Hg(II) was 5.2 and 4.7% (n = 6), respectively. Due to the quantitative extraction of Hg(II) from 1000 mL of the sample solution an enhancement factor as large as 1230-fold can be obtained. The proposed method has been validated using a certified reference materials, and also the method has been applied successfully for the determination of Hg(II) in aqueous samples.     

Determination of Silver by Flame Atomic Absorption Spectrometry after Preconcentration on Naphthalene Modified with Dithizone

A solid‐phase extraction method for preconcentration of silver and consequent determination by atomic absorption spectrometry is described. The method is based on the adsorption of silver on naphthalene modified with dithizone in a column. The adsorbed silver is eluted from the column with a thiourea solution and determined by flame atomic absorption spectrometry. The adsorption conditions including pH, reagent concentration, eluent volume, flow rate and interfering ions were investigated. The calibration graph was linear in the range 10–1000 ng mL^?1 of Ag in the initial solution with r = 0.9998. The limit of detection based on 3S_b was 3.9 ng mL^?1. The relative standard deviation for ten replicate measurements of 40 and 600 ng mL^?1 of Ag was 4.4% and 0.9%, respectively. The method was applied to the determination of silver in mineral, radiology film and wound dressing samples.     

Rapid Determination of Dissolved Phosphorus in Environmental Waters Using Inductively Coupled Plasma Tandem Mass Spectrometry

Dissolved phosphorus (P), an important bioavailable nutrient element, is one of the key indicators of eutrophication levels, and has been routinely measured for decades in aquatic environments. The current EPA recommended colorimetric method has been criticized for its time-consuming step of sample preparation and generation of toxic waste through the use of heavy metal catalysts. In this study, a fast, accurate, and interference-free method for the determination of dissolved P in environmental waters based on inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) was developed. This ICP-MS/MS was operated in the MS/MS mode to provide an interference-free measurement. The developed method exhibited excellent linearity (R² = 0.9999) over a concentration range of 0.5–500 μg L^?1, with a limit of detection of 8.1 ng L^?1 in 5% nitric acid solutions. The recoveries (90%–105% in water samples) and the concentrations determined by this method were in good agreement with those determined using the recommended colorimetric method. Comparing with the colorimetric method, the proposed method for determination of dissolved P exhibited great advantages such as shorter experiment time, lower limit of detection and higher sample throughput.     

Determination of Gold by Flame Atomic Absorption Spectrometry with Hollow Fiber Liquid Phase Microextraction Using Room Temperature Ionic Liquids

A novel method to preconcentrate gold was developed employing a synergistic enhancement of a room temperature ionic liquid combined with hollow fiber liquid phase micro-extraction with flame atomic absorption spectrometry detection. The method is based on the complexation of gold with dithizone. The formed hydrophobic complex was subsequently extracted into the lumen of a hollow fiber. The organic phase was siphoned into FAAS for the determination. A room temperature ionic liquid and dithizone were used the enhancement reagent and chelating reagent, respectively. The addition of a room temperature ionic liquid led to a five-fold improvement in the extraction of gold. The 1-octanol was immobilized in the pores of the polypropylene hollow fiber as the liquid membrane and was also used as the acceptor solution. Some parameters that influenced extraction and determination were evaluated in detail, such as concentrations of the ionic liquid and dithizone, pH of samples, stirring rates, extraction time, and interferences. Under optimized conditions, a detection limit of 0.9 ng mL^?1 and an enrichment factor of 130 were achieved. The relative standard deviation (RSD) was 3.7% for Au (40 ng mL^?1, n = 5). The proposed method was successfully applied to the determination of gold in certified reference environmental samples and ore samples with satisfactory results.     

Determination of Sulfur Compounds in Water Samples by Ion Chromatography Dynamic Reaction Cell Inductively Coupled Plasma Mass Spectrometry

An ion chromatography‐inductively coupled plasma mass spectrometric (IC‐ICP‐MS) method for the speciation of sulfur compounds, namely sulfite [SO₃^2?], sulfate [SO₄^2?] and thiosulfate [S₂O₃^2?], was described. Ionic sulfur compounds were well separated in about 3 min by ion chromatography with a Hamilton PRP‐X100 column as the stationary phase and 60 mmol L^?1 NH₄NO₃ and 0.1% v/v formaldehyde (HCHO) solution (pH = 7) as the mobile phase. The analyses were carried out using dynamic reaction cell (DRC) ICP‐MS. The sulfur‐selective chromatogram was determined at m/z 48 as ³²S¹⁶O⁺ by using its reaction with O₂ in the reaction cell. The method avoided the effect of polyatomic isobaric interferences at m/z 32 caused by ¹⁶O¹⁶O⁺ and ¹⁴N¹⁸O⁺ on ³²S⁺ by detecting ³²S⁺ as the oxide ion ³²S¹⁶O⁺ at m/z 48, which is less interfered. The detection limit of various species studied was in the range of 3.6–4.6 ng S mL^?1. The accuracy of the method has been verified by comparing the sum of the concentrations of individual sulfur compounds obtained by the present procedure with the total concentration of sulfur in several natural water samples. The recovery was in the range of 97–102% for various compounds studied.     

Separation and preconcentration of ultra trace amounts of beryllium in water samples using mixed micelle-mediated extraction and determination by inductively coupled plasma-atomic emission spectrometry

In the present study a cloud point extraction process using mixed micelle of the cationic surfactant cetyl-pyridinium chloride (CPC) and non-ionic surfactant Triton X-114 for extraction of beryllium from aqueous solutions is developed. The extraction of analyte from aqueous samples was performed in the presence of 1,8-dihydroxyanthrone as chelating agent in buffer media of pH 9.5. After phase separation, the surfactant-rich phase was diluted with 0.4 mL of a 60:40 methanol-water mixture containing 0.03 mL HNO₃. Then, the enriched analyte in the surfactant-rich phase was determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The different variables affecting the complexation and extraction conditions were optimized. Under the optimum conditions (i.e. 1.6 × 10⁻⁴ mol L⁻¹ 1,8-dihydroxyanthrone, 1.2 × 10⁻⁴ mol L⁻¹ CPC, 0.15% (v/v) Triton X-114, 50 °C equilibrium temperature) the calibration graph was linear in the range of 0.006-80 ng mL⁻¹ with detection limit of 0.001 ng mL⁻¹ and the precision (R.S.D.%) for five replicate determinations at 18 ng mL⁻¹ of Be(II) was better than 2.9%. In this manner the preconcentration and enrichment factors were 16.7 and 24.8, respectively. Under the presence of foreign ions no significant interference was observed. Finally, the proposed method was successfully utilized for the determination of this cation in water samples.     

Low-temperature electrothermal vaporization of thenoyltrifluoroacetone complex of Sc(III) and Y(III) for sample introduction in an inductively coupled plasma atomic emission spectrometry,and their determination in biological samples

A new method for inductively coupled plasma atomic emission spectrometry (ICP-AES) determination of trace Sc and Y, based on gaseous compound introduction into the plasma as their thenoyltrifluoroacetone (TTA) complexes by electrothermal vaporization was developed. Using the reagent TTA as chemical modifier can not only enhance the analytical signals, but also reduce the vaporization temperature. At a temperature of 1,000 °C the trace Sc and Y can be vaporized completely into ICP. The factors affecting the formation of the chelate and its vaporization behavior, such as drying time, vaporization temperature/time, reaction medium and the amount of TTA, were investigated in detail. Under the optimized conditions (drying temperature/time 100 °C/10 s, vaporization temperature/time 1,000 °C/4 s), the limits of detection for Sc and Y were 19 pg and 34 pg (3), respectively, and the relative standard deviations for Sc and Y were 4.2% (c _Sc=0.2 g mL^–1; n=7) and 2.6% (c _Y=0.5 g mL^–1; n=7). The linear ranges of the calibration graphs cover three orders of magnitude. The method was applied to the analysis of the biological reference materials (GBW 07602, bush branches and leaves; GBW 07604, poplar leaves), and the results obtained were in good agreement with the certified values.     

电感耦合等离子体质谱法测定高纯金中痕量杂质

建立了高纯金中40余种痕量杂质的电感耦合等离子体质谱测定方法。方法检出限为0．0006～0．21μg/L。考察了基体Au的谱干扰及基体效应,采用Cs内标补偿基体对待测信号的抑制作用。方法简单、快速、灵敏、准确。     

Synthesis of chitosan resin possessing a phenylarsonic acid moiety for collection/concentration of uranium and its determination by ICP-AES

A chitosan resin possessing a phenylarsonic acid moiety (phenylarsonic acid type chitosan resin) was developed for the collection and concentration of trace uranium prior to inductively coupled plasma (ICP) atomic emission spectrometry (AES) measurement. The adsorption behavior of 52 elements was systematically examined by packing it in a minicolumn and measuring the elements in the effluent by ICP mass spectrometry. The resin could adsorb several cationic species by a chelating mechanism, and several oxo acids, such as Ti(IV), V(V), Mo(VI), and W(VI), by an anion-exchange mechanism and/or a chelating mechanism. Especially, U(VI) could be adsorbed almost 100% over a wide pH region from pH 4 to 8. Uranium adsorbed was easily eluted with 1 M nitric acid (10 mL), and the 25-fold preconcentration of uranium was achieved by using a proposed column procedure, which could be applied to the determination of trace uranium in seawater by ICP-AES. The limit of detection was 0.1 ng mL⁻¹ for measurement by ICP-AES coupled with 25-fold column preconcentration.     

Synthesis of salicylaldehyde-modified mesoporous silica and its application as a new sorbent for separation, preconcentration and determination of uranium by inductively coupled plasma atomic emission spectrometry

A new functionalized mesoporous silica (MCM-41) using salicylaldehyde was utilized for the separation, preconcentration and determination of uranium in natural water by inductively coupled plasma atomic emission spectrometry (ICP-AES).Experimental conditions for effective adsorption of trace levels of U(VI) were optimized. The preconcentration factor was 100 (1.0 mL of elution for a 100 mL sample volume). The analytical curve was linear in the range 2-1000 μg L⁻¹ and the detection limit was 0.5 ng mL⁻¹. The relative standard deviation (R.S.D.) under optimum conditions was 2.5% (n = 10). Common coexisting ions did not interfere with the separation and determination of uranium at pH 5. The sorbent exhibited excellent stability and its sorption capacity under optimum conditions has been found to be 10 mg of uranium per gram of sorbent. The method was applied for the recovery and determination of uranium in different water samples.     

Speciation of Mercury in Microalgae by Isotope Dilution-inductively Coupled Plasma Mass Spectrometry

Species-specific stable isotope dilution in combination with gold trap- or gas chromatography (GC)-inductively coupled plasma mass spectrometry (ICP-MS) is reported for the determination of inorganic mercury and methylmercury in diatoms (Chaetoceros curvisetus). The optimum conditions for the separation parameters were established. The isotope dilution analysis was performed using ¹⁹⁹Hg-enriched Hg²⁺ and laboratory-synthesized ²⁰¹Hg-enriched methylmercury. The absolute detection limits obtained with isotope dilution-ICP-MS were 9 pg for total mercury and 0.6 pg for methylmercury. The relative error of 7 Hg isotopic abundances based on the peak area measurements was better than 2.0% for 20 pg of methylmercury (as Hg) and 250 pg of inorganic mercury. The accuracy of the method was validated with a biological certified reference material. The developed method was then applied to investigate the uptake of inorganic mercury and methylmercury by C. curvisetus. Continuous uptake of inorganic mercury and methylmercury was observed during 5 days of incubation.     

Speciation analysis of inorganic arsenic in natural water by carbon nanofibers separation and inductively coupled plasma mass spectrometry determination

In this paper, carbon nanofibers (CNFs) as a novel solid phase extraction sorbent were developed for speciation preconcentration and separation of inorganic arsenic species As(III) and As(V) prior to determination by inductively coupled plasma mass spectrometry (ICP-MS). It was found that during all the steps of the separation, As(III) was selectively sorbed on the microcolumn packed with CNFs within a pH range of 1.0-3.0 in the presence of ammonium pyrroinedithiocarbamate (APDC), while As(V) was passed through the microcolumn without the retention. Various experimental parameters affecting the separation and determination of As(III) and As(V) have been investigated in detail. Under the optimized conditions, the detection limits of this method for As(III) were 0.0045 ng mL⁻¹ with an enrichment factor of 33 and 0.24 ng mL⁻¹ for As(V), and the relative standard deviations for As(III) and As(V) were 2.6% and 1.9% (n = 9, c = 1.0 ng mL⁻¹), respectively. In order to verify the accuracy of the method, a certified reference of water sample was analyzed, and the results obtained were in good agreement with the certified values. The proposed method was applied for the analysis of inorganic arsenic species in groundwater and lake water with the recovery of 92-106%.     

Quantification of Teprenone in Human Plasma by HPLC Coupled to Mass Spectrometry: Application to a Bioequivalence Study

A rapid, sensitive, and specific method has been developed for quantification of teprenone (TEP) in human plasma. The analytes were isolated from plasma by liquid–liquid extraction with t-butyl methyl ether. The extracts were analyzed by high-performance liquid chromatography coupled to mass spectrometry (HPLC–MS); gefarnate was used as internal standard (IS). HPLC separation of the analytes was performed on a C₁₈ column with 1:54:45 (v/v) 1% aqueous acetic acid–methanol–acetonitrile as mobile phase; the flow rate was 0.2 mL min^?1. The compounds were ionized by atmospheric-pressure chemical ionization (APCI). Calibration plots for TEP were linear in the range 20.0–2000.0 ng mL^?1; correlation coefficients were >0.9981. The average extraction efficiency for TEP was >67%, method recovery was >95%, the limit of detection (LOD) was 1.0 ng mL^?1, and the intraday and interday coefficients of variation were <7%. This HPLC–MS procedure was used to assess the bioequivalence of TEP tablet and capsule formulations. A single 150-mg dose of each formulation was administered to 18 healthy male volunteers. The study was conducted using an open, randomized, two-period crossover design with a 1-week wash-out interval. Because the 90% CI for C _max and the ratios of the AUCs were all within the 80–125% range stipulated by the US Food and Drug Administration, it was concluded that the TEP tablet and capsule formulations were bioequivalent in terms of rate and extent of absorption.     

Colorimetric Determination of Lead Using Gold Nanoparticles

A combined homogeneous assay and colorimetric determination method using gold nanoparticles was developed for rapid determination of lead(II) in contaminated natural waters. The presence of lead(II) in the colloidal gold suspension causes a change in the absorbance of the suspension. An increase in the absorption property at 595 nm is accompanied by a change in the size of the gold nanoparticles. High concentrations of lead cause aggregation of the gold colloids. Colloidal gold nanoparticles were synthesized using tannic acid as the reducing agent; this reagent allowed selective determination of lead in 10 µL of water, with a detection limit of 310 ng mL^?1 with an analysis time of 5 min. The coefficient of variation for lead(II) within the working range of the assay (520 ng mL^?1–13 µg mL^?1) varied from 1.3% to 9.2%. The limit of detection using this method with a sample volume of 50 µL was 60 ng mL^?1. The coefficient of variation for lead over the working range of the determined concentrations (80 ng mL^?1–25 µg mL^?1) varied from 0.2% to 9.3%, while the values for the inter-day assay (n = 8) were less than 10%. The method was employed for the analysis of river, lake, marsh, and spring water; the recovery of lead was determined to be 72.5%–130% for 10 µL of water and 93.6%–114.7% for 50 µL.     

Analysis of Silver Nanoparticles Using Single-Particle Inductively Coupled Plasma – Mass Spectrometry (ICP-MS): Parameters Affecting the Quality of Results

Single–particle analysis using inductively coupled plasma mass spectrometry offers a new tool for the characterisation of inorganic nanoparticles. Its development is connected with new generations of ultrafast spectrometers. This work is concerned with thorough investigation of parameters affecting the quality of the analysis of Ag nanoparticles, i.e., nanoparticle stability, transport efficiency and sensitivity of determination. The short-term stability of Ag nanoparticles in demineralised water can be prolonged to at least 7?h by the addition of 0.05% gelatin. The sensitivity was affected by plasma power and the nebuliser Ar flow. The transport efficiency decreased with increasing sample uptake, so a compromise between the efficiency and the total number of particles entering the spectrometer should be selected. The estimate of transport efficiency is distorted when more concentrated dispersions of nanoparticles are analysed because of the overlapping of signals of multiple nanoparticles. This effect was observed for dispersions of concentration greater than 1?×?10⁶?mL^?1 where an apparent decrease in transport efficiency from an initial value 7–8% to 1% was observed. The following parameters were found by method validation: concentration limit of detection of 97?mL^?1, nanoparticle diameter limit of detection 15?nm, linearity from 20 to at least 100?nm and repeatability of 1.3%. After validation, the method was applied to determine Ag nanoparticles in river water from the Vltava in Prague. Nanoparticles with diameters of 32–114?nm were found, and their number concentration increased from 340?mL^?1 to 1670?mL^?1 as the stream of water passed through urban agglomeration.     

Determination of hafnium at the 10% level (relative to zirconium content) using neutron activation analysis,inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry

Hafnium at the very low level of 1–8 ppm (in relation to zirconium) was determined in zirconium sulfate solutions (originating from investigations of the separation of ca. 44 ppm Hf from zirconium by means of the ion exchange method) by using three independent methods: inductively coupled plasma mass spectrometry (ICP MS), neutron activation analysis (NAA) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results of NAA and ICP MS determinations were consistent with each other across the entire investigated range (the RSD of both methods did not exceed 38%). The results of ICP-AES determination were more diverse, particularly at less than 5 ppm Hf (RSD was significantly higher: 29–253%). The ion exchange method exploiting Diphonix^® resin proved sufficient efficiency in Zr–Hf separation when the initial concentration ratio of the elements ([Zr]₀/[Hf]₀) ranged from 1200 to ca. 143,000.