A viscosity-sensitive iridium(iii) probe for lysosomal microviscosity quantification and blood viscosity detection in diabetic mice.

Abnormal levels of biological viscosity are closely associated with some diseases and malfunction (e.g. cancer, diabetes). Sensitive viscosity probes are of significant importance in disease diagnosis and remain an unmet need. In this research, we present a novel viscosity-sensitive dinuclear Ir(iii) complex (1), which freely rotates and shows weak phosphorescence in a low-viscosity environment, while in viscous media, both the phosphorescence intensity and lifetime are enhanced significantly. 1 can further be applied for phosphorescence lifetime imaging (PLIM) and measure lysosomal microviscosity with high accuracy and reliability. Interestingly, this PLIM property can distinguish between tumorous and nontumorous cells. Importantly, the probe shows much stronger phosphorescence in the fresh blood of diabetic mice than that of normal mice. This work offers a potential efficient probe for diagnosing viscosity related diseases.

Half-Sandwich Iridium and Ruthenium Complexes: Effective Tracking in Cells and Anticancer Studies.

Half-sandwich metal-based anticancer complexes suffer from uncertain targets and mechanisms of action. Herein we report the observation of the images of half-sandwich iridium and ruthenium complexes in cells detected by confocal microscopy. The confocal microscopy images showed that the cyclopentadienyl iridium complex 1 mainly accumulated in nuclei in A549 lung cancer cells, whereas the arene ruthenium complex 3 is located in mitochondria and lysosomes, mostly in mitochondria, although both complexes entered A549 cells mainly through energy-dependent active transport. The nuclear morphological changes caused by Ir complex 1 were also detected by confocal microscopy. Ir complex 1 is more potent than cisplatin toward A549 and HeLa cells. DNA binding studies involved interaction with the nucleobases 9-ethylguanine, 9-methyladenine, ctDNA, and plasmid DNA. The determination of bovine serum albumin binding was also performed. Hydrolysis, stability, nucleobase binding, and catalytic NAD+/NADH hydride transfer tests for complexes 1 and 3 were also carried out. Both complexes activated depolarization of mitochondrial membrane potential and intracellular ROS overproduction and induced cell apoptosis. Complex 3 arrested the cell cycle at the G0/G1 phase by inactivation of CDK 4/cyclin D1. This work paves the way to track and monitor half-sandwich metal complexes in cells, shines a light on understanding their mechanism of action, and indicates their potential application as theranostic agents.

Mitochondrial imaging in live or fixed tissues using a luminescent iridium complex.

Mitochondrial morphology is important for the function of this critical organelle and, accordingly, altered mitochondrial structure is exhibited in many pathologies. Imaging of mitochondria can therefore provide important information about disease presence and progression. However, mitochondrial imaging is currently limited by the availability of agents that have the capacity to image mitochondrial morphology in both live and fixed samples. This can be particularly problematic in clinical studies or large, multi-centre cohort studies, where tissue archiving by fixation is often more practical. We previously reported the synthesis of an iridium coordination complex [Ir(ppy)2(MeTzPyPhCN)]+; where ppy is a cyclometalated 2-phenylpyridine and TzPyPhCN is the 5-(5-(4-cyanophen-1-yl)pyrid-2-yl)tetrazolate ligand; and showed that this complex (herein referred to as IraZolve-Mito) has a high specificity for mitochondria in live cells. Here we demonstrate that IraZolve-Mito can also effectively stain mitochondria in both live and fixed tissue samples. The staining protocol proposed is versatile, providing a universal procedure for cell biologists and pathologists to visualise mitochondria.

Real-Time Verification of a High-Dose-Rate Iridium 192 Source Position Using a Modified C-Arm Fluoroscope.

PURPOSE: High-dose-rate (HDR) brachytherapy misdeliveries can occur at any institution, and they can cause disastrous results. Even a patient's death has been reported. Misdeliveries could be avoided with real-time verification methods. In 1996, we developed a modified C-arm fluoroscopic verification of an HDR Iridium 192 source position prevent these misdeliveries. This method provided excellent image quality sufficient to detect errors, and it has been in clinical use at our institutions for 20 years. The purpose of the current study is to introduce the mechanisms and validity of our straightforward C-arm fluoroscopic verification method. METHODS AND MATERIALS: Conventional X-ray fluoroscopic images are degraded by spurious signals and quantum noise from Iridium 192 photons, which make source verification impractical. To improve image quality, we quadrupled the C-arm fluoroscopic X-ray dose per pulse. The pulse rate was reduced by a factor of 4 to keep the average exposure compliant with Japanese medical regulations. The images were then displayed with quarter-frame rates. RESULTS: Sufficient quality was obtained to enable observation of the source position relative to both the applicators and the anatomy. With this method, 2 errors were detected among 2031 treatment sessions for 370 patients within a 6-year period. CONCLUSIONS: With the use of a modified C-arm fluoroscopic verification method, treatment errors that were otherwise overlooked were detected in real time. This method should be given consideration for widespread use.

Solid-phase extraction of iridium from soil and water samples by using activated carbon cloth prior to its spectrophotometric determination.

A solid-phase extraction method for separation and preconcentration of Ir(IV) ion by using activated carbon cloth (ACC) has been presented. Ir(IV) as their 1-(2-pyridylazo) 2-naphtol (PAN) chelate was adsorbed on ACC at pH 2.0 and was eluted from ACC with acidic dimethylformamide (DMF). The Ir(IV) concentration was determined at 536 nm as Ir(IV)-PAN complex by using UV-vis spectrophotometer. The analytical parameters including pH, sample and eluent flow rates, amount of PAN, eluent type, concentration, and sample volume were optimized. The effects of foreign ions on the recoveries of iridium were also investigated. The preconcentration factor was calculated as 60. The limit of detection (LOD) and the limit of quantification (LOQ) of the method were found as 0.039 and 0.129 µg L(-1), respectively. The method was applied to soil and water samples for iridium determination.

Luminescence-based retrospective dosimetry using Al2O3 from mobile phones: a simulation approach to determine the effects of position.

Monte Carlo modelling has been performed in support of efforts to establish emergency dosimetry services based on optically or thermally stimulated luminescence (OSL/TL) of the Al(2)O(3) substrate present on the resistors found in mobile phones, which can act as fortuitous retrospective dosemeters for photon exposures. Specifically, a range of exposure conditions has been modelled to assess the dependence of the dosimetry on factors such as the position of resistors within a phone, the orientation of the phone relative to the source, and the location of the phone relative to its owner. Variations due to the resistors' positions and the phone's orientation were generally found to contribute just a few percent to the uncertainty on the dose assessments, though the electrical contacts surrounding the resistors could potentially enhance these by several 10s of percent. But, the location of the phone was found to impact dosimetry greatly. The largest discrepancies in the results were found for low-energy exposures: for (192)Ir, differences of up to an order-of-magnitude were found between resistor and whole body doses. The outcome of the work was to derive correction / calibration factors that can be applied to estimate whole body doses from OSL/TL readings, the accurate application of which would depend on the knowledge of the exposure geometry and the degree of conservatism acceptable for the dose assessment.

Spatial variation of contaminant elements of roadside dust samples from Budapest (Hungary) and Seoul (Republic of Korea), including Pt, Pd and Ir.

Roadside dusts were studied to explain the spatial variation and present levels of contaminant elements including Pt, Pd and Ir in urban environment and around Budapest (Hungary) and Seoul (Republic of Korea). The samples were collected from six sites of high traffic volumes in Seoul metropolitan city and from two control sites within the suburbs of Seoul, for comparison. Similarly, road dust samples were obtained two times from traffic focal points in Budapest, from the large bridges across the River Danube, from Margitsziget (an island in the Danube in the northern part of Budapest, used for recreation) as well as from main roads (no highways) outside Budapest. The samples were analysed for contaminant elements by ICP-AES and for Pt, Pd and Ir by ICP-MS. The highest Pt, Pd and Ir levels in road dusts were found from major roads with high traffic volume, but correlations with other contaminant elements were low, however. This reflects automobile catalytic converter to be an important source. To interpret the obtained multi-element results in short, pollution index, contamination index and geo-accumulation index were calculated. Finally, the obtained data were compared with total concentrations encountered in dust samples from Madrid, Oslo, Tokyo and Muscat (Oman). Dust samples from Seoul reached top level concentrations for Cd-Zn-As-Co-Cr-Cu-Mo-Ni-Sn. Just Pb was rather low because unleaded gasoline was introduced as compulsory in 1993. Concentrations in Budapest dust samples were lower than from Seoul, except for Pb and Mg. Compared with Madrid as another continental site, Budapest was higher in Co-V-Zn. Dust from Oslo, which is not so large, contained more Mn-Na-Sr than dust from other towns, but less other metals.

In situ and ex situ low-field NMR spectroscopy and MRI endowed by SABRE hyperpolarization.

By using 5.75 and 47.5 mT nuclear magnetic resonance (NMR) spectroscopy, up to 10(5)-fold sensitivity enhancement through signal amplification by reversible exchange (SABRE) was enabled, and subsecond temporal resolution was used to monitor an exchange reaction that resulted in the buildup and decay of hyperpolarized species after parahydrogen bubbling. We demonstrated the high-resolution low-field proton magnetic resonance imaging (MRI) of pyridine in a 47.5 mT magnetic field endowed by SABRE. Molecular imaging (i.e. imaging of dilute hyperpolarized substances rather than the bulk medium) was conducted in two regimes: in situ real-time MRI of the reaction mixture (in which pyridine was hyperpolarized), and ex situ MRI (in which hyperpolarization decays) of the liquid hyperpolarized product. Low-field (milli-Tesla range, e.g. 5.75 and 47.5 mT used in this study) parahydrogen-enhanced NMR and MRI, which are free from the limitations of high-field magnetic resonance (including susceptibility-induced gradients of the static magnetic field at phase interfaces), potentially enables new imaging applications as well as differentiation of hyperpolarized chemical species on demand by exploiting spin manipulations with static and alternating magnetic fields.

Combined two-photon excitation and d→f energy transfer in a water-soluble Ir(III)/Eu(III) dyad: two luminescence components from one molecule for cellular imaging.

The first example of cell imaging using two independent emission components from a dinuclear d/f complex is reported. A water-stable, cell-permeable Ir(III) /Eu(III) dyad undergoes partial Ir→Eu energy transfer following two-photon excitation of the Ir unit at 780 nm. Excitation in the near-IR region generated simultaneously green Ir-based emission and red Eu-based emission from the same probe. The orders-of-magnitude difference in their timescales (Ir ca. µs; Eu ca. 0.5 ms) allowed them to be identified by time-gated detection. Phosphorescence lifetime imaging microscopy (PLIM) allowed the lifetime of the Ir-based emission to be measured in different parts of the cell. At the same time, the cells are simultaneously imaged by using the Eu-based emission component at longer timescales. This new approach to cellular imaging by using dual d/f emitters should therefore enable autofluorescence-free sensing of two different analytes, independently, simultaneously and in the same regions of a cell.

Fate of platinum metals in the environment.

For many years now automotive exhaust catalysts have been used to reduce the significant amounts of harmful chemical substances generated by car engines, such as carbon monoxide, nitrogen oxides, and aromatic hydrocarbons. Although they considerably decrease environmental contamination with the above-mentioned compounds, it is known that catalysts contribute to the environmental load of platinum metals (essential components of catalysts), which are released with exhaust fumes. Contamination with platinum metals stems mainly from automotive exhaust converters, but other major sources also exist. Since platinum group elements (PGEs): platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru) and iridium (Ir) seem to spread in the environment and accumulate in living organisms, they may pose a threat to animals and humans. This paper discusses the modes and forms of PGE emission as well as their impact on the environment and living organisms.

Phosphorescent cellular probes and uptake indicators derived from cyclometalated iridium(III) bipyridine complexes appended with a glucose or galactose entity.

A series of phosphorescent cyclometalated iridium(III) polypyridine complexes appended with a ß-D-glucose moiety [Ir(N^C)2(bpy-TEG-ONCH3-ß-D-glc)](PF6) [bpy-TEG-ONCH3-ß-D-glc = 4-(10-N-methyl-N-(ß-D-glucopyranosyl)-amino-oxy-2,5,8-trioxa-dec-1-yl)-4'-methyl-2,2'-bipyridine; HN^C = 2-((1,1'-biphenyl)-4-yl)benzothiazole) (Hbt) (1a), 2-phenylpyridine (Hppy) (2a), 2-phenylquinoline (Hpq) (3a), 7,8-benzoquinoline (Hbzq) (4a)] has been synthesized and characterized. The D-galactose counterparts [Ir(N^C)2(bpy-TEG-ONCH3-ß-D-gal)](PF6) [bpy-TEG-ONCH3-ß-D-gal = 4-(10-N-methyl-N-(ß-D-galactopyranosyl)-amino-oxy-2,5,8-trioxa-dec-1-yl)-4'-methyl-2,2'-bipyridine; HN^C = Hbt (1b), Hppy (2b), Hpq (3b), Hbzq (4b)] and a sugar-free bt complex [Ir(bt)2(bpy-TEG-OMe)](PF6) [bpy-TEG-OMe = 4-(2,5,8,11-tetraoxa-dodec-1-yl)-4'-methyl-2,2'-bipyridine] (1c) have also been prepared. Upon photoexcitation, all the complexes displayed intense and long-lived triplet metal-to-ligand charge-transfer ((3)MLCT) [dπ(Ir) → π*(N^N)] or triplet intraligand ((3)IL) (π → π*) (N^C and N^N) emission. The lipophilicity, the cellular uptake efficiency, and cytotoxicity of the complexes toward human cervix epithelioid carcinoma cells (HeLa) have been examined. Temperature dependence and chemical inhibition experiments indicated that the transport of bt-glucose complex 1a across the cell membrane occurred through an energy-requiring process such as endocytosis, in additional to a pathway that was mediated by glucose transporters (GLUTs). Importantly, the cellular uptake efficiency of this complex was found to be strongly dependent on hormonal stimulation and inhibition, rendering it a new phosphorescent metabolic indicator. Additionally, laser-scanning confocal microscopy revealed that the complex was localized in the mitochondria and highly resistant to photobleaching compared to a fluorescent organic glucose derivative 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxy-d-glucose (2-NBDG).

Large Pt anomaly in the Greenland ice core points to a cataclysm at the onset of Younger Dryas.

One explanation of the abrupt cooling episode known as the Younger Dryas (YD) is a cosmic impact or airburst at the YD boundary (YDB) that triggered cooling and resulted in other calamities, including the disappearance of the Clovis culture and the extinction of many large mammal species. We tested the YDB impact hypothesis by analyzing ice samples from the Greenland Ice Sheet Project 2 (GISP2) ice core across the Bølling-Allerød/YD boundary for major and trace elements. We found a large Pt anomaly at the YDB, not accompanied by a prominent Ir anomaly, with the Pt/Ir ratios at the Pt peak exceeding those in known terrestrial and extraterrestrial materials. Whereas the highly fractionated Pt/Ir ratio rules out mantle or chondritic sources of the Pt anomaly, it does not allow positive identification of the source. Circumstantial evidence such as very high, superchondritic Pt/Al ratios associated with the Pt anomaly and its timing, different from other major events recorded on the GISP2 ice core such as well-understood sulfate spikes caused by volcanic activity and the ammonium and nitrate spike due to the biomass destruction, hints for an extraterrestrial source of Pt. Such a source could have been a highly differentiated object like an Ir-poor iron meteorite that is unlikely to result in an airburst or trigger wide wildfires proposed by the YDB impact hypothesis.

Phosphorescence bioimaging using cyclometalated Ir(III) complexes.

Recent advances in the development of the phosphorescent Ir(III) complexes have made it possible to implement the phosphorescence modality in bioimaging applications. A variety of phosphorescent Ir(III) complexes have been synthesized and assessed in the context of in vitro and in vivo imaging, especially in subcellular organelle staining and the sensing of biologically important analytes. The examples presented here demonstrate that Ir(III) complexes provide attractive alternatives to fluorescent organic compounds in the construction of biolabels and biosensors. The complexes are particularly advantageous with respect to fluorescent compounds in their compatibility with time-gated bioimaging techniques that completely eliminate background signals due to autofluorescence.

Phosphorescent imaging of living cells using a cyclometalated iridium (III) complex.

A cell permeable cyclometalated iridium(III) complex has been developed as a phosphorescent probe for cell imaging. The iridium(III) solvato complex [Ir(phq)2(H2O]2)] preferentially stains the cytoplasm of both live and dead cells with a bright luminescence.

Accumulation of impact markers in desert wetlands and implications for the Younger Dryas impact hypothesis.

The Younger Dryas impact hypothesis contends that an extraterrestrial object exploded over North America at 12.9 ka, initiating the Younger Dryas cold event, the extinction of many North American megafauna, and the demise of the Clovis archeological culture. Although the exact nature and location of the proposed impact or explosion remain unclear, alleged evidence for the fallout comes from multiple sites across North America and a site in Belgium. At 6 of the 10 original sites (excluding the Carolina Bays), elevated concentrations of various "impact markers" were found in association with black mats that date to the onset of the Younger Dryas. Black mats are common features in paleowetland deposits and typically represent shallow marsh environments. In this study, we investigated black mats ranging in age from approximately 6 to more than 40 ka in the southwestern United States and the Atacama Desert of northern Chile. At 10 of 13 sites, we found elevated concentrations of iridium in bulk and magnetic sediments, magnetic spherules, and/or titanomagnetite grains within or at the base of black mats, regardless of their age or location, suggesting that elevated concentrations of these markers arise from processes common to wetland systems, and not a catastrophic extraterrestrial impact event.

The effect of zinc levels in a gold-based alloy on porcelain-metal bonding.

OBJECTIVES: The purpose of this study was to ascertain whether the amount of Zn in gold alloys contributes to porcelain-metal bonding. METHODS: Experiments were carried out using a commercial Pd-free gold alloy with a nominal composition of 88.7 wt% Au, 9.49 wt% Pt, 1.5 wt% Zn, 0.1 wt% Mn, 0.2 wt% Rh, and 0.1 wt% Ir, which contains Zn and no other elements (In, Sn, Fe) known to affect porcelain-metal bond strength. To establish the effect of oxidation of the metal surface, porcelain was applied both to preoxidized and to non-preoxidized metal specimens. The bond strength was evaluated by means of the ISO 9693: 1999 crack initiation test. A conventional gold alloy was used as a control. The elemental distributions at the porcelain/alloy interfaces were analyzed in cross section by electron probe microanalysis. Additionally, after the bond strength test, cross-sections of the interfaces of the debonded specimens were microscopically analyzed to characterize the fracture mode. RESULTS: The Pd-free gold alloy joints showed significantly higher bond strength values than joints made with conventional gold alloy. Preoxidation treatment significantly increases the bond strength, in the preoxidized joints Zn was highly localized at the interface and diffused into the porcelain up to about 10 µm from the interface, and the joint failed by cohesive fracture in the porcelain. In contrast, the non-preoxidized joint showed mainly adhesive fracture at the porcelain/alloy interface. SIGNIFICANCE: The presence of Zn in gold alloys plays a part in establishing chemical bonding thus improving the bond strength between porcelain and alloy.

Consistency of vendor-specified activity values for ¹9²Ir brachytherapy sources.

A long-term comparison was done between the manufacturer-stated ¹9²Ir activity and the measured ¹9²Ir activities determined with a well-type ionization chamber. Sources for a Nucletron Micro Selectron high-dose-rate (HDR) unit were used for this purpose. The radioactive sources reference activities were determined using a PTW well-type ionization chamber traceable to the National Institute of Standards and Technology Primary Calibration Laboratory. The measurements were taken in a period of 56 months with 17 different radioactive sources. The manufacturer stated activities were taken from the source calibration certificate provided by the manufacturer. These values were compared with the measured activities. The results have shown that both the percentage deviation of the monthly control measurements with the well-type chamber and the ratio between the measured activities to the manufacturer-stated value lie within ± 2.5%. These results were compared with similar published data and with uncertainty level (3% of the mean and 5% maximum deviation from mean) for brachytherapy sources calibration recommended by the AAPM. It was concluded that a threshold level of ±2.5% can be used as a suitable quality assurance indicator to spot problems in our department. The typical ±5% uncertainty as provided by the manufacturers may be tightened to ±3% to be more in line with published AAPM reports.

A phantom study of an in vivo dosimetry system using plastic scintillation detectors for real-time verification of 192Ir HDR brachytherapy.

PURPOSE: The goal of the present work was to evaluate the accuracy of a plastic scintillation detector (PSD) system to perform in-phantom dosimetry during 192Ir high dose rate (HDR) brachytherapy treatments. METHODS: A PSD system capable of stem effect removal was built. A red-green-blue photodiode connected to a dual-channel electrometer was used to detect the scintillation light emitted from a green scintillation component and transmitted along a plastic optical fiber. A clinically relevant prostate treatment plan was built using the HDR brachytherapy treatment planning system. An in-house fabricated template was used for accurate positioning of the catheters, and treatment delivery was performed in a water phantom. Eleven catheters were inserted and used for dose delivery from 192Ir radioactive source, while two others were used to mimic dosimetry at the rectum wall and in the urethra using a PSD. The measured dose and dose rate data were compared to the expected values from the planning system. The importance of removing stem effects from in vivo dosimetry using a PSD during 192Ir HDR brachytherapy treatments was assessed. Applications for dwell position error detection and temporal verification of the treatment delivery were also investigated. RESULTS: In-phantom dosimetry measurements of the treatment plan led to a ratio to the expected dose of 1.003 +/- 0.004 with the PSD at different positions in the urethra and 1.043 +/- 0.003 with the PSD inserted in the rectum. Verification for the urethra of dose delivered within each catheter and at specific dwell positions led to average measured to expected ratios of 1.015 +/- 0.019 and 1.014 +/- 0.020, respectively. These values at the rectum wall were 1.059 +/- 0.045 within each catheter and 1.025 +/- 0.028 for specific dwell positions. The ability to detect positioning errors of the source depended of the tolerance on the difference to the expected value. A 5-mm displacement of the source was detected by the PSD system from 78% to 100% of the time depending on the acceptable range value. The implementation of a stem effect removal technique was shown to be necessary, particularly when calculating doses at specific dwell positions, and allowed decreasing the number of false-error detections-the detection of an error when it should not be the case--from 19 to 1 for a 5% threshold out of 43 measurements. The use of the PSD system to perform temporal verification of elapsed time by the source in each catheter--generally on the order of minutes--was shown to be in agreement within a couple of seconds with the treatment plan CONCLUSIONS: We showed that the PSD system used in this study, which was capable of stem effect removal, can perform accurate dosimetry during 192Ir HDR brachytherapy treatment in a water phantom. The system presented here shows some clear advantages over previously proposed dosimetry systems for HDR brachytherapy, and it has the potential for various online verifications of treatment delivery quality.

Catalytic-adsorptive stripping voltammetric determination of ultra-trace iridium(III). Application to fresh- and sea-water.

An extremely sensitive stripping voltammetric procedure for ultra-trace determination of iridium(III) is reported. The method is based on the interfacial accumulation of the iridium(III)-CTAB complex onto the glassy carbon electrode, followed by the catalytic reduction of the adsorbed complex in the presence of bromate. 0.3 mol L(-1) acetate buffer pH 4.7+6.9×10(-2) mol L(-1) NaBrO(3)+2.7×10(-5)mol L(-1) cetyltrimethylammonium bromide (CTAB)+0.2 mol L(-1) KCl was employed as the supporting electrolyte. The analytical procedure was verified by the analysis of the standard reference materials: Sea Water BCR-CRM 403 and Fresh Water NIST-SRM 1643d. The accuracy, expressed as relative error e%, was satisfactory, being lower than 6%, while precision as repeatability, expressed as relative standard deviation s(r)%, was generally lower than 5%. The limit of detection was of the order of 2-3 ng L(-1). Once set up on the standard reference materials, the analytical procedure was transferred and applied to superficial water sampled in proximity to superhighway and in the Po river mouth area.

Flow injection analysis combined with a hydrothermal flow reactor: application to kinetic determination of trace amounts of iridium using a water-soluble porphyrin.

A new type of flow injection analysis (FIA) system combined with an extremely high temperature reactor, namely hydrothermal flow injection analysis (HT-FIA), has been successfully constructed for the first time. Fundamental characteristics of HT-FIA system, such as limit temperature, pressure, and flow rate, were examined as an analytical tool. To demonstrate the potential of HT-FIA, the catalytic activity of Ir(IV) for the degradation of a water-soluble porphyrin, 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid (TPPS), was applied for the determination of trace amounts of Ir(IV). Although the indicator reaction is very slow at room temperature, HT-FIA system enables to accelerate the reaction. A linear calibration curve was acquired at 10(-8)M level of Ir(IV) and the interferences of platinum group metal ions were examined. The detection limit of Ir(IV) was 5.8 × 10(-9)M and a fairly high-throughput analysis, of which more than 30 samples can be analyzed within 80 min, was achieved.