电感耦合等离子体发射光谱法测定地质样品中钨时对锌的光谱干扰校正

采用硝酸-氢氟酸-高氯酸消解样品,电感耦合等离子体发射光谱法测定地质样品中的钨. 讨论了Zn207.908对W 07.911的光谱干扰,并应用光谱干扰系数校正法(IEC)校正干扰. 结果表明:Zn对W的光谱干扰可以用IEC进行有效的消除,进行光谱校正后的结果明显优于未加校正的试验结果.     

∧-related Quantum Interference of ^2П [Case（a）] Diatom on Rotational Energy Transfer

To study theoretically the relationship between the integral interference angle and the scat- tering angle in collisional quantum interference, the integral interference angle of atom- ^2П[case（a）] diatomic molecules system is described. To simulate the experiment theoretically, the theoretical model on collision-induced rotational energy transfer in an atom- ^2П[case（a）]diatom system is presented based on the first order Born approximation taking into account of the long-range interaction potential. For the ^2П electronic state in the Hund＇s case（a） diatom, the degree of the interference is discussed. The interference angles of collision-induced rotational energy transfer of CN（A^2П） in Hund＇s case（a） with He, Ne, and Ar are calculated quantitatively. The key parameters in the determination of integral interference angles are obtained.     

Wavelet-Based Method for Time-Domain Noise Analysis and Reduction in a Frequency-Scan Ion Trap Mass Spectrometer

We adopt an orthogonal wavelet packet decomposition (OWPD) filtering approach to cancel harmonic interference noises arising from an AC power source in time domain and remove the resulting rf voltage interference noise from the mass spectra acquired by using a charge detection frequency-scan quadrupole ion trap mass spectrometer. With the use of a phase lock resampling technique, the transform coefficients of the rf interference in signals become a constant, exhibiting a shift of the baseline in different rf phases. The rf interference is therefore removable by shifting the baselines back to zero in OWPD coefficients. The approach successfully reduces the time-domain background noise from 1367 electrons (rms) to 408 electrons (rms) (an improvement of 70?%) and removes the high frequency noise components in the charge detection ion trap mass spectrometry. Unlike other smoothing or averaging methods commonly used in the mass-to-charge (m/Ze) domain, our approach does not cause any distortion of original signals.     

电感耦合等离子体质谱法测定水中低浓度铁受钙干扰的消除

采用电感耦合等离子体质谱法测定水中小于0.06 mg·L-1铁量时受到共存的钙(40mg·L-1)的严重干扰。经验证,钙的干扰可借以下途径消除:①采用碰撞池和56Fe、57Fe两同位素中的任一种,钙的干扰均可忽略不计。②如采用非碰撞池,则钙的干扰将因铁与其共存钙的质量浓度的不同而变化:(a)当cFe<0.10mg·L-1,cCa<1mg·L-1,并采用57Fe同位素时,钙的干扰可以忽略;(b)当cFe<0.10mg·L-1,cCa>1mg·L-1时,采用两同位素中的任一种都无法克服钙的严重干扰;(c)当cFe>0.10mg·L-1,cCa<5mg·L-1,无论采用同位素56Fe或57Fe,钙的干扰都不明显,而如cCa>5mg·L-1时,则只能用同位素56Fe才可避免钙的干扰。     

The effects of CopperZinc and CopperCadmium intermetallic compounds in different systems used for anodic stripping voltammetry

The CuZn intermetallic compound resulting from simultaneous deposition of copper and zinc at a hanging mercury drop electrode (HMDE) and at preformed mercury film electrodes (MFE) has been studied. Goals were to determine what conditions can be used to avoid intermetallic compound formation and to reduce errors that result from the method of standard additions. For Cu²⁺ and Zn²⁺ concentrations in the ng ml⁻¹ range, the use of shortened preconcentration times in conjunction with a differential pulse stripping waveform and the HMDE show significant reduction in the extent of the interference. The CuCd interference was also characterized at performed MFE's and at MFE's deposited in situ from 5–300 μg ml⁻¹ mercury(II) solutions. No significant interference with the cadmium stripping were was observed with preformed MFE's, but peak depression was observed when the electrodes were deposited in situ. The degree of interference was found to decrease with both increased mercury(II) concentrationa and decreased copper(II) concentration. Errors in the standard addition method are minimal when the copper(II) concentration is not significantly altered.     

Electrothermal atomization of palladium stabilized selenium in the presence of phosphate

The interference caused by phosphate (as Na₂HPO₄) in the electrothermal atomic absorption determination of selenium was investigated for reduced and unreduced palladium nitrate modifiers. An increase of the amount of phosphate in the sample was accompanied with increasing losses of selenium. Kinetic parameters of the selenium atomization were calculated for various amounts of phosphate interference. These results were compared with previous findings for palladium stabilized selenium and the sulfate interference observed for this system. The increasing chemical interference is due to phosphorous replacing the selenium bound by palladium. The phosphorus thus makes the palladium surface unavailable for the stabilization of selenium.     

Systematic computer-aided interpretation of infrared and raman vibrational spectra based on the crise program

The CRISE computer program is used to correlate wavenumber regions and 6 structural elements containing carbon, hydrogen and oxygen on the basis of 2 standard files with 549 infrared and Raman spectra. The degree of correlation, including score percentages and interfering percentages, is established for different types of intervals in relation to various intensity thresholds. Specific regions (score 100%, interference 0%) proved to be rare, whereas pseudo-specific regions (score < 100%, interference 0%) are normally present. The usefulness of selective regions (score 100%, interference > 0%) is doubtful. The infrared and Raman results for a structural element can differ appreciably, yet neither technique is clearly superior for interpretative purposes.     

电感耦合等离子体发射光谱(ICP-OES)法测定水泥熟料中铬的干扰研究

电感耦合等离子体发射光谱法（ICP-OES）测定重金属时常面临干扰问题。为提高ICP-OES测定水泥熟料中铬的准确度,研究选取了Cr205.560、Cr267.716和Cr283.563三条谱线,根据水泥熟料中主量元素（铁、铝、钙和镁）含量,设计不同浓度单元素干扰试验,结果表明：铁对Cr283.563谱线测定有较大的正干扰,钙对三条谱线均有较大的负干扰,两者导致的相对误差（RE）均在±10%以上,其他一般为负干扰,RE在±10%以内。进一步线性回归分析发现,除铝外,其他干扰元素的干扰大小与浓度呈强线性相关性。通过多元素复合干扰试验发现干扰导致的RE约为-18%~11%,同单元素干扰加和结果比较,两者相差约为8%~10%。实际样品检测结果表明实际干扰同多元素复合干扰试验基本相同,Cr283.563谱线测定结果误差可能更小,三条谱线的实际样品加标回收率大致相当,约为80%,经回收率修正,Cr205.560和Cr267.716谱线结果满意,而Cr283.563谱线误差较大。以多元素复合干扰试验溶液作为基体,采用基体匹配法测定可基本消除干扰影响。以钙溶液作为基体的简化基体匹配法同样有效,但仅可选用Cr205.560和Cr267.716谱线。本研究从实际干扰问题出发,通过系统分析问题,找到干扰的原因,并据此提出消除干扰方法,提高了测定铬的准确度,也为检测人员解决相关干扰问题提供借鉴。     

浅析锡对电感耦合等离子体质谱法测定镉的干扰

在不同的工作条件下,分析了不同Sn(锡)/Cd(镉)比值下Sn对电感耦合等离子体质谱法(ICP-MS)测定Cd的干扰程度,并将经过在线干扰校正和离线干扰校正后的Cd浓度与标准值比较,实验结果表明:当样品中Sn浓度与Cd浓度比值在2以下时,Sn对Cd的干扰很小,Cd的测定值不用经过任何方式校正也比较接近标准值;当Sn浓度与Cd浓度比值在2~30时,采用离线校正和在线校正后的Cd测定值与标准值均比较接近;当Sn浓度与Cd浓度比值大于30时,采用离线校正才能获得更满意的结果。     

Feasibility of using beryllium as internal reference to reduce non-spectroscopic carbon species matrix effect in the inductively coupled plasma–mass spectrometry (ICP-MS) determination of boron in biological samples

The mechanism by which carbon matrix species cause non-spectroscopic matrix interference on boron (B) and beryllium (Be) during the determination of B in biological samples is investigated. The study indicates that, unlike other matrix species such as Ca and Na that cause non-spectroscopic matrix interference only through space charge effect, carbon species manifest non-spectroscopic interference by two mechanisms. The minor non-spectroscopic interference of carbon is through space charge effect. However, the major non-spectroscopic effect of carbon is by a charge transfer mechanism from C⁺-species to B and Be atoms in the central channel of the plasma discharge. The large difference in the magnitude of the carbon charge transfer non-spectroscopic matrix interference between Be and B makes Be unsuitable as an internal reference for B in solutions containing more than 1500 μg/ml dissolved organic carbon (DOC). This DOC content is approximately half the DOC usually present in the final sample solution for B determination in biological samples. However, Be still acts as a perfect internal reference to B in solution containing matrix elements that exert their non-spectroscopic interference effect through space charge mechanism (such as Na, K, Ca, etc.).     

Hydrogen Chloride Improved Selectivity of Lead Ionic Selective Electrode (Pb‐ISE) under High Calcium Concentration

Leachants from the toxic characteristic leaching procedure (TCLP) of combustion residues, fly ash, usually contain calcium and lead ions as high as to 12000 and 1000 ppm, respectively. In this paper, the authors used a commercialized lead(II) ionic‐selective electrode (Pb‐ISE) to measure the lead(II) concentrations in such leachants and observed a serious interference from calcium(II) ions. The interference starts at the concentration ratio of ([Ca]/[Pb]) in the sample over 2.0. Reasons for the interference are not clear, but it can be suppressed by adding a chemical modifier, HCl_(aq) solution, into the sample. The authors have found that the optimized addition amount in TCLP leachants is 4 mL of HCl_(aq) per 20 mL sample, and the detection limit of the Pb‐ISE was 5.2 ppm.     

Investigation of cobalt interference on lead hydride generation with tetrahydroborate(III) in the presence of hexacyanoferrate(III)

The interference of Co(II) on plumbane generation with tetrahydroborate in the presence of hexacyanoferrate(III) was studied with a new mechanism proposed to explain the interference. The products that were obtained, following reactions of a CoCl₂ solution with tetrahydroborate(III), which interfere with plumbane generation, were precipitated and investigated by inductively-coupled plasma-atomic emission spectrometry and -mass spectrometry (ICP-OES and ICP-MS). Batch experiments of the potentiometer analysis and pH determination were performed to investigate a mechanism of Co(II) interference on plumbane generation, the role of hexacyanoferrate(III) on plumbane generation, and the function of the masking agent on Co(II) interference. The preferentially formed nanoscale catalytic and magnetic cobalt borides in the redox system cause a potential for a strong reducing condition and induces the precipitation of Fe(III) and Pb(II) in the solution, which is counter to plumbane generation. Potassium thiocyanate/oxalic acid/1,10-phenanthroline, as the combined masking agent and working with hexacyanoferrate(III), decreases the amount of borides in the precipitates and acts as a kind of buffer of the redox potential, which maintains the conditions for plumbane generation. This hydride generation method has been applied to the direct determination of trace Pb in cobalt oxide standard reference materials with a detection limit of 0.3 µg L^− 1.     

Spectrophotometric determination of iron and cobalt with Ferrozine and dithizone

Procedures are described whereby iron (1–50 μg) and cobalt (1–25 μg) are determined spectrophotometrically, iron as iron(II) with the disodium salt of 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (Ferrozine) and cobalt as the cobalt(III) dithizonate complex. The reduction to iron(II) prevents interference of iron(III) in the cobalt determination, and both metals can be determined in the same portion of sample solution. Removal of interference by other metal ions is described.     

Interference transition dipole in mixed-valence compounds

Electronic transitions between Kramers doublets are often allowed for σ (x,y) and π(z) electric or magnetic dipole radiation and transverse MCD measures the interference between σ and π transition dipoles. For mixed-valence compounds, transverse MCD measures the interference between electron transfer (z) and single-ion (x,y) transition dipoles.     

Removal of metabolite interference during liquid chromatography/tandem mass spectrometry using high‐field asymmetric waveform ion mobility spectrometry

The effect of metabolite interference during liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis of an amine drug was investigated using FAIMS (high‐Field Asymmetric waveform Ion Mobility Spectrometry). The selected reaction monitoring (SRM) transition used for the drug exhibited an interference due to in‐source conversion of the N‐oxide metabolite to generate an ion isobaric with the drug. The on‐line FAIMS device removed the metabolite interference before entrance to the mass spectrometer. FAIMS was used to demonstrate the relative accuracy and precision of drug analysis even in the presence of a co‐eluting metabolite that may undergo in‐source conversion. Copyright © 2005 John Wiley & Sons, Ltd.     

Inter-orbital interference in STM tip during electron tunneling in tip–sample system: influence on STM images

We present a theoretical study of the influence of interference effects connected with the tunneling through s and p_z orbitals of the apex atom in STM tip on the formation of STM image. The results show that such an interference may modify significantly the tunneling current by changing the current contributions from the different orbitals in the tip–sample system. STM simulations have been performed for the Al(0 0 1) surface and different fcc-metal tips: they clearly indicate that the height and type of the STM corrugation depend considerably on this interference.     

Evaluation of on-line desalter-inductively coupled plasma-mass spectrometry system for determination of Cr(III), Cr(VI), and total chromium concentrations in natural water and urine samples

We have developed a simple and convenient method for the determination of Cr(III), Cr(VI), and the total chromium concentrations in natural water and urine samples that use a flow injection on-line desalter-inductively coupled plasma-mass spectrometry system. When using aqueous ammonium chloride (pH 8) as the stripping solution, the severe interference from sodium in the matrix can be eliminated prior to inductively coupled plasma-mass spectrometry measurement, and the Cr(VI) level can be determined directly. To determine the total concentration of Cr in natural water and urine samples, we used H₂O₂ or HNO₃ to decompose the organic matter and convert all chromium species into the Cr(VI) oxidation state. To overcome the spectral interference caused by the matrix chloride ion in the resulting solutions, we employed cool plasma to successfully suppress chloride-based molecular ion interference during the inductively coupled plasma-mass spectrometry measurement. By significantly eliminating interference from the cationic and anionic components in the matrices prior to the inductively coupled plasma-mass spectrometry measurement, we found that the detection limit reached 0.18 μg L^− 1 (based on 3 sigma). We validated this method through the analysis of the total chromium content in two reference materials (NIST 1643c and 2670E) and through measuring the recovery in spiked samples.     

生物样品二恶英分析中两个常见干扰峰的鉴定

利用高分辨气相色谱/高分辨质谱联用仪（HRGC/HRMS）和高分辨气相色谱/低分辨质谱仪（HRGC/LRMS）对实际生物样品中二恶英（polychlorinated dibenzo-p-dioxins and dibenzofurans,PCDD/Fs）的分析过程中¹³C标记的2,3,7,8-四氯代二苯并呋喃（¹³C₁₂-2,3,7,8-TCDF）监测碎片离子通道的两个常见干扰峰进行了分析鉴定。通过实际样品分析结果首先推测这两个干扰峰可能为有机氯农药类化合物滴滴涕（DDT）降解产物滴滴伊（DDE）的两个异构体,其次采用DDE的标准溶液（包括o,p’-DDE和p,p’-DDE）进行分析确认。通过HRGC/HRMS的色谱峰分离效果分析、色谱保留时间匹配以及与DDE碎片离子的理论丰度比进行比较,最终确认实际样品分析中的两个干扰峰依次为o,p’-DDE和p,p’-DDE。本文可为生物样品中二恶英的准确识别提供重要参考。     

Dealing with interference challenge in the electrochemical detection of As(III) —A complexometric masking approach

Copper ion has been reported to be a major interference in the electrochemical detection of arsenic (III) ion in water. Therefore the development of a simple approach to alleviate this interference challenge is important. We present the use of ammonia solution as a masking agent for Cu(II) interference in the square wave anodic stripping voltammetry of As(III) on a gold nanoparticle modified glassy carbon electrode (GCE). AuNPs were electrochemically deposited by cyclic voltammetry on a GCE from a potential range of − 400 mV to 1100 mV for 10 cycles. Square wave anodic stripping voltammetry (SWASV) was used to detect As(III) in water with and without Cu(II) based on the following optimised conditions: pH = 3, deposition potential = − 600 mV, and deposition time = 60 s. Ammonia solution was added to the analyte solution and the effect on mitigating copper interference was studied. The presence of ammonia complexed the Cu(II) ion thereby excluding Cu(II) from interfering with the As(III) signal.     

The problem of arsenic interference in the analysis of Cd to evaluate its extractability in soils contaminated by arsenic

The arsenic (As) spectral interference observed in the determination of cadmium (Cd) by inductively coupled plasma atomic emission spectrometry (ICP-AES) was studied in atomic absorption spectrometry (AAS) using flame (FAAS) and graphite furnace (GFAAS) as atomizers. The soils of 15 kitchen gardens located near two smelters in the North of France were selected according the ratio As/Cd. Four different extracting solutions usually used to evaluate the mobility of Cd were chosen to extract Cd from these soil samples: citric acid 0.11 M, acetic acid 0.11 M, calcium chloride 0.01 M and water. The quantitative determinations of Cd in the 15 soils for each solvent were investigated by ICP-AES at two lines (228.802 and 214.438 nm) and by FAAS or GFAAS with two-way background compensation. Compared to the Cd concentrations measured in the acid solutions and in the CaCl₂ solution after the addition of a chemical modifier, it was clearly demonstrated that the high-speed self-reversal background compensation (HSSR-method) was the method of choice to eliminate the spectral interference of As during Cd determination by FAAS and by GFAAS. In water, it was shown that the deuterium lamp used for the background compensation (D₂-method) was able to eliminate the most of the As interference. In comparison with Cd concentrations in water after adding a chemical modifier, those obtained with the HSSR-method were similar and a very good correlation was obtained between these two methods (R² = 0.995). It was therefore established that the HSSR-method would be able to replace the chemical modifiers to eliminate As interference in the determination of Cd-extractable from As contaminated soils.