ICP-AES法同时测定石英砂中的痕量元素

采用微波溶样，并通过条件试验，建立了微波溶样ICP－AES法同时测定石英砂中13种痕量元素的分析方法并已应用于实际样品的分析，方法的相对标准偏差≤10％，加标回收率为90％－107％。     

Ion chromatographic determination of phosphorus soluble in different extracting media in fertilizers

A new method based on ion chromatography (IC) was developed for the determination of phosphorus in fertilizers. Fertilizers were extracted with water, mineral acids, and 2% formic acid, 2% citric acid, and neutral ammonium citrate solutions according to European Regulation No. 2003/2003 of the European Parliament and the Council of October 13, 2003, or the Decree of the Italian Agriculture Minister of June 17, 2002; the extracts were analyzed by direct injection, after simple filtration, by IC on an IonPac AS19 (250 x 4 mm id) column, using a KOH (21-50-21 mM) gradient and suppressed conductivity detection. The calibration plot was linear over the range of 5-50 mg/L (r(2) of >0.999). The method was evaluated by comparison with a gravimetric method according to established norms. Associated uncertainty at the 95% confidence level was established as 0.47% for the determination of 3-46% P2O5 by IC. A good chromatographic separation of phosphorus forms such as phosphates and phosphites, and some other important anions like nitrates, chlorides, and sulfates present in many commercial fertilizers was also possible, with a linear response over the range of 5-50 mg/L. After a more complete validation, this IC determination of phosphorus could replace more tedious methods such as those using gravimetric determinations.     

Ion chromatographic determination of lithium at trace level concentrations: Application to a tracer experiment in a high-mountain lake

The water residence time of a high-mountain seepage lake in the Austrian Alps was derived from the flushing rate of a tracer substance. A diluted lithium chloride solution was injected into the lake during holomictic conditions in order to favour the homogeneous distribution of the tracer. The exponential decline of the mass of lithium in the lake revealed a water residence time of 1.5 to 3 months for summer and almost no lake water exchange during winter. Lithium concentrations ranged from background values of 0.06 μg l⁻¹ to about 3 μg l⁻¹ immediately after the tracer injection. Lake water samples were analyzed with ion-exchange chromatography using a Dionex device with a CS 12A separation column. The method detection limit determined according to the definition of the US Envirinmental Protection Agency amounted to 0.009 μg l⁻¹.     

Ion chromatographic separations of phosphorus species: a review

The aim of this paper is to review recent literature regarding the determination of phosphorus species by ion chromatography (IC), and describe the implementation of new developments in sample treatment and ion chromatography methodology for the analysis of these compounds. Ion-exchange methods using both carbonate/hydrogencarbonate and hydroxide selective columns in combination with self-regenerating membrane and solid-phase-based suppressors enable determination of phosphate down to ppb levels. New technology, particularly on-line electrolytic hydroxide generators and electrolytic self-regenerating suppressor devices, has allowed the use of elution gradients in both carbonate/hydrogencarbonate and hydroxide selective systems, improving sensitivity and reducing total analysis time for samples containing phosphate together with other inorganic anions. In addition to a review of these developments, optimization and application of chromatographic methods using reversed stationary phases and cationic and/or zwitterionic surfactants is also discussed.The objective of most of the IC methods developed for phosphorus species is the determination of phosphate and total phosphorus. Therefore, sample treatment and separation conditions specifically developed for this purpose are also described. In addition, application of IC to the analysis of other inorganic (reduced and condensed) and organic (phytates, alkyl phosphate, and phosphonates) phosphorus species is discussed along with methodology and relevant applications in water analysis and other miscellaneous fields.     

Ion chromatographic determination of trace amounts of aluminium with on-line preconcentration and spectrophotometric detection

Trace amounts of aluminium in aqueous samples can be determined by ion chromatography using ammonium sulphate-nitric acid as eluent and pyrocatechol violet as post-column chromogenic reagent. The detection limit for a 50-μl sample is 10 μg 1^?1. Preconcentration of the sample (obtained by replacing the sampling loop with a short ion-exchange column) allows larger amounts of sample to be loaded and lowers the detection limit below 1 μg 1^?1.     

Simultaneous ion chromatographic determination of selenium and metal ions in waters at trace level

Summary An ion-chromatographic procedure is described for the determination of selenium (VI) at μg L⁻¹ level in the presence of anions and heavy metal ions. Maximum permissible concentrations and effects from each interfering substance were investigated for the Se concentration range 12.5–1,000 μg L⁻¹. The method, optimized for the detection of SeO ₄ ²⁻ , gives results suitable for speciation analysis. Total selenium can be determined after complete conversion to selenate ion by oxidation with KMnO₄. The detection limit of selenium is 4.8 μg L⁻¹ (0.96 ng for 200 μL sample). Paper presented at the 41st Pittsburgh Conference, New York, March 5–9, 1990.     

Ion chromatographic determination of platinum in biotic materials

A method for the determination of platinum is presented. The procedure consists of a high-pressure digestion of the sample followed by an ion Chromatographic separation. Then the platinum chloro complex is detected by UV-absorption.     

On-line preconcentration,ion chromatographic separation and spectrophotometric determination of palladium at trace level

A new method for the determination of Pd by ion chromatography and spectrophotometric detection has been developed. The technique is based on the separation of palladium as PdCl4(2-) by anion exchange and on the detection, at a wavelength of 407 nm, of metal as PdI4(2-) after a post-column reaction with KI. The column used was an IonPac AS4 with HCl and HClO4 eluents. The eluent concentration and composition of post-column reagent were optimised in order to obtain the best separation and sensitivity for Pd. In order to reduce the detection limit, an on-line preconcentration step, has been optimised. The method, as developed, was suitable for palladium determination within a 300 ng/l D.L. value. The method applied to a BCR reference material (CRM 277, estuarine sediment) gave satisfactory results in agreement with the certified value within a D.L. value of 1.3 microg/l for the real sample.     

Ion chromatographic behaviour and determination of perbromates

Ion chromatographic behaviour of perbromates in aqueous solutions was studied, using ion suppressed conductimetric detection (Dionex DX-100 ion chromatograph with ASRS-I suppressor). Various eluents (sodium hydroxide, carbonate and phenate solutions) were examined using the AS-14  mm anion-exchange column and an optimization study concerning pH and total eluate concentration of mobile phase was carried out. Phenate buffer (20.0 mM, pH 11.0) at 1.18 ml/min flow rate, gave the best results. Calibration curve was linear in the range of 1.5-200 ppm, with a limit of detection of 0.46 ppm and R.S.D. 1.8% (100 ppm standard). Perbromates were separated with good resolution from potentially interfering anions (bromides, bromates, iodides, perchlorates). Selectivity coefficients were determined for perbromates, perchlorates and iodides, from linear plots of retention volume versus the reciprocal of eluent concentration. The new method was used to monitor the perbromate reactions with lactic acid, iodide and citric acid in the absence and presence of Fe(II) acting as an inducer. Furthermore, it was confirmed the inability of various common strong oxidative media to oxidize bromate to perbromate.     

Enzyme-based determination of cholesterol using the quartz crystal acoustic wave sensor

We have used the AT-cut quartz crystal sensor to measure in real-time the total cholesterol concentration in buffer and serum, using the trienzyme system of cholesterol esterase (ChE), cholesterol oxidase (ChOx) and horseradish peroxidase (HRP). The hydrogen peroxide produced from the ChE-ChOx reaction oxidises diaminobenzidine (DAB), in the presence of HRP. The response of the sensor to cholesterol is optimal in the presence of 0.1% (v/v) Triton X-100 at 0.2 U/ml ChOx, and 1 U/ml ChE. A response is obtained in less than 25 min. Using the optimal concentrations of the reagents, the linear range for free cholesterol and low density lipoprotein (LDL) cholesterol determination was between 50 and 300 μM, and 25 and 400 μM, respectively. It was found that the concentration of high density lipoprotein (HDL) cholesterol could not be determined because it solubilised the oxidised DAB, leading to poor adsorption at the crystal surface. We obtained a response to the use of cholesterol in serum at 300 μM, demonstrating that this biosensor could be used for cholesterol determination in clinical samples.     

Ion chromatographic determination of sugar phosphates in physiological samples

Ion chromatography is shown to be capable of simultaneous determination of biologically important anions. Application of this technique is illustrated for the separation and quantification of the major anions present in rat brain and liver tissues. Sugar phosphates and carboxylic acids are separated on high-performance anion-exchange columns and are detected using chemically suppressed conductivity. Detection limits range from 20 to 100 pmol for the anions tested, including inositol phosphates, lactate, pyruvate, glucuronic acid-1-phosphate, fructose-6-phosphate and glucose-6-phosphate. The coefficient of variation for the determination of most anions was in the range 5-10%. Many of these anions are either difficult to separate with other methods, or require expensive radiochemical techniques for detection. This method should be applicable to other biological studies, from the flow of carbons in photosynthesis to the study of synaptic transmission.     

Ion chromatographic determination of selected ions in antarctic ice

Ion chromatography is used to measure the concentrations of chloride, nitrate, sulphate, ammonium and sodium ions at the μg l^?1 level in Antarctic ice and to investigate the occurrence of methanesulphonate, fluoride, formate, acetate and nitrite. Of the latter group of ions, only methanesulphonate was found in measurable concentrations.     

Sample digestion procedures for trace element determination

A survey is given of both dry and wet procedures for matrix dissolution for the purpose of trace element determination in all kinds of materials. Various methods are compared and evaluated. With wet digestion methods special attention is paid to mixtures of strong acids and oxidants. Emphasis is laid on the completeness of these digestions, for which the use of HF is a prerequisite.     

A quartz crystal microbalance sensor for the determination of nitroaromatics in landfill gas

A new sensor based on oxidative combustion of nitroaromatics to NO₂ and its detection with a quartz crystal microbalance (QCM) coated with copper phthalocyanine (CuPc) was developed for determination of nitroaromatics in landfill gas. An alternative method based on gas chromatography–mass spectrometry (GC–MS) was also used in order to assess the performance of the proposed method. The results show that the analytical apparatus based on the QCM is less expensive than the GC–MS, and that the analytical error is 0.8% for both methods.     

Comparison of digestion methods for ICP-MS determination of trace elements in fish tissues

A comparison is presented of six methods involving nitric acid in conjunction with other reagents to digest three certified marine biological samples (DOLT-3, DORM-3, IAEA-407) and a fish bone homogenate (prepared from Merluccius australis). An inductively coupled plasma-mass spectrometer with an octopole collision cell was used to determine up to 40 elements (Li, B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Y, Ag, Cd, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Pb, Th, U) in the digests. These results were assessed in terms of their accuracy and precision, and a flow chart was developed to aid the selection of the optimal digestion method. Although none of the methods was found to give accurate determinations for all elements in the different reference materials, a relatively simple method involving nitric acid and hydrogen peroxide heated in a domestic microwave oven gave the most acceptable results.     

Polarographic determination of zirconium at trace level

An indirect polarographic method has been developed for the determination of zirconium by formation of molybdozirconophosphoric acid, its extraction with MIBK or a mixture of diethyl ether and 1-butanol, stripping with alkali and measurement of the Mo(VI) by its catalytic effect on the polarographic reduction of hydrogen peroxide. Depending on the extradant, a detection limit of 2.5 or 8.9 mu/gl, can be achieved.     

Net analyte signal-based simultaneous determination of ethanol and water by quartz crystal nanobalance sensor

Net analyte signal (NAS)-based method called HLA/GO was applied for the selectively determination of binary mixture of ethanol and water by quartz crystal nanobalance (QCN) sensor. A full factorial design was applied for the formation of calibration and prediction sets in the concentration ranges 5.5-22.2 μg mL⁻¹ for ethanol and 7.01-28.07 μg mL⁻¹ for water. An optimal time range was selected by procedure which was based on the calculation of the net analyte signal regression plot in any considered time window for each test sample. A moving window strategy was used for searching the region with maximum linearity of NAS regression plot (minimum error indicator) and minimum of PRESS value. On the base of obtained results, the differences on the adsorption profiles in the time range between 1 and 600 s were used to determine mixtures of both compounds by HLA/GO method. The calculation of the net analytical signal using HLA/GO method allows determination of several figures of merit like selectivity, sensitivity, analytical sensitivity and limit of detection, for each component. To check the ability of the proposed method in the selection of linear regions of adsorption profile, a test for detecting non-linear regions of adsorption profile data in the presence of methanol was also described. The results showed that the method was successfully applied for the determination of ethanol and water.     

Recent development in liquid phase microextraction for determination of trace level concentration of metals—A review

As the drive towards green extraction methods has gained momentum in recent years, it has not always been possible to eliminate organic solvents completely. However, the volumes employed have been reduced remarkably, so that a single microdrop is sufficient in some cases. This effort has led to the development of various liquid phase microextractions namely single drop microextraction (SDME), hollow fiber liquid phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME) and solidified floating organic drop microextraction (SFODME). In this review, the historical development and overview of these miniaturized liquid phase extraction methodologies have briefly been discussed and a comprehensive collection of application of the these methods in combination with different analytical techniques for preconcentration and determination of ultra trace amounts of metals and organometal ions in various matrices have been summarized.     

电感耦合等离子体质谱法同时测定成品烟烟丝中7种微量元素

采用微波消解前处理样品,电感耦合等离子体质谱检测,同时测定了成品烟烟丝中Cr、Ni、Cu、As、Se、Cd、Pb等7种微量元素。方法的回收率92.8%~120%,检出限25.2~245 ng/L,相对标准偏差均小于10%。分析和比较了5种国外卷烟和10种国内卷烟烟丝中7种元素的含量。