Biomedical subjects

Hui Ma

Publications and source records attributed to Hui Ma.

At least 19 recordsLinked to original sources

PubMed2007

The binding of FKBP23 to BiP modulates BiP's ATPase activity with its PPIase activity.

Peptidyl-prolyl cis-trans-isomerases (PPIases) are enzymes that can cis-trans-isomerize a Xaa-Pro peptide bond. Three families of PPIases are known: cyclophilins, FKBPs, and parvulins. The physiological functions of the PPIases are only poorly understood. In previous work, we reported that the mouse FK506-binding protein 23 (mFKBP23), which comprises an N-terminal PPIase domain and a C-terminal domain with Ca(2+)-binding sites, binds to mBiP in the endoplasmic reticulum (ER) and this binding is affected by the Ca(2+) concentration. In this study, we demonstrate the ability of mFKBP23 to modulate the ATPase activity of BiP, and that the bound mFKBP23, but not the free mFKBP23, can suppress the ATPase activity of mBiP through its PPIase activity.

Adenosine Triphosphatases↗

PubMed2006

A comparison between photon counting histogram and fluorescence intensity distribution analysis.

Photon counting histogram (PCH) and fluorescence intensity distribution analysis (FIDA) are two methods that were developed independently but reported almost simultaneously. Both of them have been successfully applied to fluorescence fluctuation spectroscopy (FFS). Though publications have indicated that they are theoretically equivalent, they are still commonly considered as different methods, especially in their ways to treat the point spread functions (PSFs). In this paper, the two methods are examined in detail for a direct comparison. After a direct proof of the theoretical equivalence, the authors further point out that PCH and FIDA are completely equivalent in the way of modeling PSFs; that is, any modeling approach developed from one of them can always be applied to the other. It is also demonstrated that simplified FIDA and PCH formulas in the form of power series can be applied for fast and precise numerical calculations. The two methods are also compared for their merits in the calculation efficiency.

Journal Article↗

PubMed2006

Benign intraspinal osteoblastoma stemming from C7 lamina in cervicothoracic junction: a case report.

STUDY DESIGN: A case report of a rare benign osteoblastoma successfully treated with total en bloc excision. OBJECTIVES: To describe the clinical and radiographic features of an adolescent female patient with intraspinal osteoblastoma in cervicothoracic junction and the effect of surgical treatment. SUMMARY OF BACKGROUND DATA: A rare case of massive benign osteoblastoma stemming from left side lamina of C7 and extension to spinal canal from C6 to T1 resulting in spinal cord compressed severely is reported. And the excellent results achieved from surgical intervention are presented. METHODS: A 13-year-old girl complained of gradually increasing pain of her lower part of the neck and left shoulder radiating to the left upper extremity, and the neurologic deficits were found in physical examination. A massive neoplasm located in intraspinal cervicothoracic junction and the spinal cord compressed severely was shown in radiographs, MRI, and CT. The neoplasm was removed totally with instrumentation performed in surgical intervention. She was followed up for 2.5 years; clinical symptoms and plain radiograph and CT films were investigated. RESULTS: The specimen of the removed mass was proven osteoblastoma pathologically. Her symptoms were relieved and the neurologic deficits recovered completely. Recurrence of the tumor was not seen at the final follow-up. CONCLUSIONS: A case of massive intraspinal osteoblastoma stemming from C7 lamina was successfully treated by excised grossly with instrumentation for reconstruction of stability.

Adolescent↗

PubMed2006

Anterior debridement and bone grafting of spinal tuberculosis with one-stage instrumentation anteriorly or posteriorly.

Between 2000 and 2004, 40 cases (average age 38, range 16-65 years) of spinal tuberculosis were treated with anterior debridement and iliac bone graft with one-stage anterior or posterior instrumentation in our unit. All patients received at least 2 weeks of regular antituberculous chemotherapy before surgery. We followed up all patients for 12-48 months (mean 22 months). Local symptoms of all patients were relieved significantly 1-3 weeks postoperatively; 23 of 25 cases (92%) with neurogical deficit had excellent or good clinical results. Erythrocyte sedimentation rates (ESR) returned from 51 mm/h to 32 mm/h (average) two weeks postoperatively. Kyphosis degrees were corrected by a mean of 16 degrees . Fusion rate of the grafting bone was 72.5% one year postoperatively and 90% two years postoperatively. Severe complications did not occur. We therefore believe that patients undergoing anterior debridement and iliac bone grafting with one-stage anterior or posterior instrumentation achieve satisfactory clinical and radiographic outcomes.

Adolescent↗

PubMed2006

Phosphatidylinositol 4-kinase IIIbeta regulates the transport of ceramide between the endoplasmic reticulum and Golgi.

The recently identified ceramide transfer protein, CERT, is responsible for the bulk of ceramide transport from the endoplasmic reticulum (ER) to the Golgi. CERT has a C-terminal START domain for ceramide binding and an N-terminal pleck-strin homology domain that binds phosphatidylinositol 4-phosphate suggesting that phosphatidylinositol (PI) 4-kinases are involved in the regulation of CERT-mediated ceramide transport. In the present study fluorescent analogues were used to follow the ER to Golgi transport of ceramide to determine which of the four mammalian PI 4-kinases are involved in this process. Overexpression of pleckstrin homology domains that bind phosphatidylinositol 4-phosphate strongly inhibited the transport of C5-BODIPY-ceramide to the Golgi. A newly identified PI 3-kinase inhibitor, PIK93 that selectively inhibits the type III PI 4-kinase beta enzyme, and small interfering RNA-mediated down-regulation of the individual PI 4-kinase enzymes, revealed that PI 4-kinase beta has a dominant role in ceramide transport between the ER and Golgi. Accordingly, inhibition of PI 4-kinase III beta either by wortmannin or PIK93 inhibited the conversion of [3H]serine-labeled endogenous ceramide to sphingomyelin. Therefore, PI 4-kinase beta is a key enzyme in the control of spingomyelin synthesis by controlling the flow of ceramide from the ER to the Golgi compartment.

1-Phosphatidylinositol 4-Kinase↗

PubMed2006

[Effects of Ginkgo biloba extract against excitotoxicity induced by NMDA receptors and mechanism thereof].

OBJECTIVE: To observe the effects of Ginkgo biloba extract (GBE) on N-methyl-D-aspartate (NMDA) excitotoxicity and focal cerebral ischemia, and further explore the neuroprotective mechanisms of GBE. METHODS: Neonatal SD rat hippocampus was taken out to make into cell suspension. immunohistochemistry with neuron nucleoprotein monoclonal antibody (NeuN) was used to calculate the percentage of NeuN positive cells. Twelve days after incubation the suspension of neurons were randomly divided into 4 groups: normal control group (exposed to normal saline for 15 min and then to DMEM without NMDA and glycine for 24 h), NMDA group (exposed to culture fluid with NMDA of the terminal concentration of 100 micromol/L and glycine of the terminal concentration of 10 micromol/L for 15 min and then to DMEM without NMDA and glycine for 24 h), MK-801 group (exposed to MK-801, an NMDAR antagonist, for 2 min, to culture fluid with NMDA for 15 min, and then to DMEM without NMDA and glycine for 24 h), and GBE pretreatment group (exposed to GBE of the terminal concentration of 150 microg/ml for 3 d, culture fluid with NMDS for 15 min, and then to DMEM without NMDA and glycine foe 24 h). Trypan blue staining was used to calculate the survival rate of the neurons. The lactic dehydrogenase (LDH) level in the supernatant of cultured cell suspension was detected. Whole-cell patch clamp recording was carried out to evaluate the modulatory effects of GBE on NMDA-activated currents in the rat hippocampal neurons. 108 SD rats were randomly divided into 5 groups: sham operation group (n = 12), standard middle cerebral artery occlusion (MCAO) group (n = 24, undergoing MCAO and then reperfusion), MK-801 acute administration group (n = 24, undergoing MCAO and immediate peritoneal administration of MK-801 1 mg/kg), GBE acute administration group (n = 24, undergoing peritoneal injection of GBE 100 mg/kg immediately after the MCAO), and GBE pretreatment group (n = 24, undergoing peritoneal administration of GBE every day for 7 days before the MCAO). The 4 groups were re-divided into 4 subgroups with 3 approximately 4 rats: 0.5 h ischemia, and 3 h, 1 d, and 7 d ischemia-reperfusion (IR) subgroups. The neurological symptoms were evaluated by Longa's scoring after the rats became conscious. The rats were killed at different time-points, their brains were taken out to undergo 2, 3, 5-triphenyl-tetrazolium chloride staining, the areas of cerebral infarction were calculated, and immunohistochemistry was used to evaluate the contents of NeuN and microtubule-associated protein (MAP-2). RESULTS: The cell viability of the GBE group was 85% +/- 5%, significantly higher than that of the NMDA group (39.8% +/- 2.1%, P < 0.01), and significantly lower than that of the MK-801 group (93.8% +/- 2.7%, P < 0.05). The LDH efflux of the GBE group was 87 U/L +/- 8 U/L, significantly lower than that of the NMDA group (138 U/L +/- 12 U/L, P < 0.01) and significantly higher than that of the MK-801 group (47 U/L +/- 7 U/L, P < 0.05). The inward current (I(NMDA)) of the NMDA group was significantly activated, The inhibitory rate of the NMDA-activated I(NMDA) of the GBE group was 40% +/- 17%, significantly lower than that of the MK-801 group (78% +/- 18%, P < 0.05); After washing out with standard extracellular solution, the I(NMDA) could recover to 91% +/- 8% in the GBE group, but not in the MK-801 group (P < 0.05), which indicated that GBE had lower affinity to NMDA receptor than MK-801. The Longa's scores of the 3 h and 24 h IR subgroups of the GBS pretreatment group were all significantly lower than those of the corresponding subgroups of the standard MCAO and GBE acute administration groups. The symptoms of the MK-801 were the most severe. Cerebral infarction began to appear in the 1-day subgroups. The cerebral infarction areas of the 1 d subgroups of the GBF pretreatment and MK-801 groups were 11.5% +/- 1.3% and 6.5% +/- 0.9% respectively, both significantly smaller than those of the MCAO and GBE acute administration groups (24.5% +/- % and 22.9% +/- 1.3% respectively, both P < 0.01), however, there was no significant difference in the cerebral infarction area between the GBE acute administration and MCAO group. It was true too for the cerebral infarction areas of the 7 d subgroups. Except in the control group, loss of NeuN positive neuron was seen in all groups, especially the MCAO and GBE acute administration groups. Except in the control group, the MAP-2 positive neurons were decreased in all groups, especially the MCAO and GBE acute administration groups, and 1 day and 7 days after the IR MAP-2 positive neurons were almost unseen in the MCAO and GBE acute administration groups, however, could be seen in small amounts in the GBE and MK-801 groups (all P < 0.01). CONCLUSION: GBE pretreatment protects the neurons from excitotoxicity induced by over-activated NMDA receptor and focal cerebral ischemia, which can be explained by the mild blocking effect of GBE on NMDA receptor with low affinity, comparing with MK-801, and GBE is expected to interfere in excitotoxicity in clinic without neurotoxic behaviors.

Animals↗

PubMed2006

Fungal surface remodelling visualized by atomic force microscopy.

Most fungal growth is localized to the tips of hyphae, however, early stages of spore germination and the growth of certain morphological mutant strains exhibit non-polarized expansion. We used atomic force microscopy (AFM) to document changes in Aspergillus nidulans wall surfaces during non-polarized growth: spore germination, and growth in a strain containing the hypA1 temperature sensitive morphogenesis defect. We compared wall surface structures of both wild-type and mutant A. nidulans following growth at 28 degrees and 42 degrees C, the latter being the restrictive temperature for hypA1. There was no appreciable difference in surface ultrastructure between wild-type and hypA1 spores, or hyphal walls grown at 28 degrees C. When dry mature A. nidulans conidia were wetted they lost their hydrophobin coat, indicating an intermediate stage between dormancy and swelling. The surface structure of hypA1 germlings grown at 42 degrees C was less organized than wild-type hyphae grown under the same conditions, and had a larger range of subunit sizes. AFM images of hyphal wall surface changes following a shift in growth temperature from restrictive (42 degrees C) to permissive (28 degrees C), showed a gradient of sizes for wall surface features similar to the trend observed for wild-type cells at branch points. Changes associated with the hyphal wall structure for A. nidulans hypA1 offer insight into the events associated with fungal germination, and wall remodelling.

Aspergillus nidulans↗

PubMed2006

Polarization-degree imaging contrast in turbid media: a quantitative study.

Scattering in biological tissue can degrade imaging contrast and reduce the probe depth. Polarization-based measurement has shown its advantages in overcoming such drawbacks. Here, linear and circular polarization degree imaging is applied to a comblike metal target submerged in Intralipid solutions. Contrasts of the metal bars are measured quantitatively as functions of the Intralipid concentration and the submersion depths. Different behaviors in contrast for linear and circular polarizations are compared. Contributions to the background of circular polarization degree images by backscattering, snake, and diffusive photons are examined carefully.

Algorithms↗

PubMed2006

Scoring a diverse set of high-quality docked conformations: a metascore based on electrostatic and desolvation interactions.

Predicting protein-protein interactions involves sampling and scoring docked conformations. Barring some large structural rearrangement, rapidly sampling the space of docked conformations is now a real possibility, and the limiting step for the successful prediction of protein interactions is the scoring function used to reduce the space of conformations from billions to a few, and eventually one high affinity complex. An atomic level free-energy scoring function that estimates in units of kcal/mol both electrostatic and desolvation interactions (plus van der Waals if appropriate) of protein-protein docked conformations is used to rerank the blind predictions (860 in total) submitted for six targets to the community-wide Critical Assessment of PRediction of Interactions (CAPRI; http://capri.ebi.ac.uk). We found that native-like models often have varying intermolecular contacts and atom clashes, making unlikely that one can construct a universal function that would rank all these models as native-like. Nevertheless, our scoring function is able to consistently identify the native-like complexes as those with the lowest free energy for the individual models of 16 (out of 17) human predictors for five of the targets, while at the same time the modelers failed to do so in more than half of the cases. The scoring of high-quality models developed by a wide variety of methods and force fields confirms that electrostatic and desolvation forces are the dominant interactions determining the bound structure. The CAPRI experiment has shown that modelers can predict valuable models of protein-protein complexes, and improvements in scoring functions should soon solve the docking problem for complexes whose backbones do not change much upon binding. A scoring server and programs are available at http://structure.pitt.edu.

Models, Biological↗

PubMed2006

Adsorption performance and mechanism in binding of Reactive Red 4 by coke waste.

The protonated coke waste was used as a new type of adsorbent for the removal of Reactive Red 4. To identify the binding sites in the protonated coke waste, the waste was potentiometrically titrated. As a result, four types of functional groups were present in the waste, which was confirmed by FT-IR analysis. Among functional groups, primary amine groups (-NH2) were likely the binding sites for anionic Reactive Red 4. It was also found that sulfonate, carboxyl and phosphonate groups played a role in electrostatic interference with the binding of dye molecules. The maximum adsorption capacities of the coke waste were 70.3+/-11.1 and 24.9+/-1.8 mg/g at pH 1 and 2, respectively. Kinetic study showed a pseudo-first-order rate of adsorption with respect to the solution. The uptake of Reactive Red 4 was not significantly affected by the high concentration of salts. These results of adsorption performance indicate the coke waste as a potentially economical adsorbent for dye removal.

Adsorption↗

PubMed2006

Extended photon counting histogram and fluorescence intensity distribution analysis approaches for optically biased photon counting statistics.

A gradient potential induced by a strongly focused laser beam can perturb the diffusion dynamics of particles in solutions and result in biased photon counting statistics in fluorescence fluctuation spectroscopy (FFS). In this paper, the theories of the photon counting histogram (PCH) and fluorescence intensity distribution analysis (FIDA) approaches are extended independently to fit the biased experimental data and retrieve the unbiased parameters, i.e., the average number of the sample particles in the focal volume N, their brightness epsilon, and polarizability alpha. The extended theories are tested using Monte Carlo simulations for single- and double-component systems. It is also proved numerically and analytically that the extended PCH and FIDA approaches are completely equivalent. Practical implementations and possible applications of extended PCH and FIDA are discussed.

Journal Article↗

PubMed2006

SMK-1, an essential regulator of DAF-16-mediated longevity.

Insulin/IGF-1 signaling (IIS) regulates aging in worms, flies, and mice through a well-characterized, highly conserved core set of components. IIS also regulates early developmental decisions, the reproductive status of the animal, innate immunity, and stress-resistance functions. In C. elegans, the sole insulin/IGF-1 receptor, DAF-2, negatively regulates the FOXO transcription factor, DAF-16. We report here on a new component of the IIS longevity pathway, SMK-1, which specifically influences DAF-16-dependent regulation of the aging process in C. elegans by regulating the transcriptional specificity of DAF-16 activity. Localization analysis of DAF-16 places SMK-1 downstream of DAF-16's phosphorylation-dependent relocation to the nucleus. Physiological and transcription analyses indicate that smk-1 is required for the innate immune, UV, and oxidative stress but not the thermal stress functions of DAF-16. SMK-1 therefore plays a role in longevity by modulating DAF-16 transcriptional specificity without affecting other processes regulated by IIS.

Aging↗

PubMed2006

Effect of surface hydrophobicity/hydrophilicity of mesoporous supports on the activity of immobilized lipase.

Taking advantage of the virtue of hydrophilic surface, lipase was firstly immobilized on SBA-15 as a support. Then the surface of the SBA-15 with enzyme entrapped inside the channels was modified by grafting with organic moieties. It has been found that the silylation with n-decyltrimethoxysilane (DE) and 3-(trimethoxysilyl)propyl methacrylate (MA) following the lipase immobilization increases the surface hydrophobicity. But the surface modified by MA shows more hydrophilicity than that modified by DE. The activity assay indicates that the hydrolytic activity for the hydrolysis of insoluble or partly soluble substrates increases with enhanced surface hydrophobicity.

Animals↗

PubMed2006

The highly charged region of plant beta-type phosphatidylinositol 4-kinase is involved in membrane targeting and phospholipid binding.

In Arabidopsis thaliana and Oryza sativa, two types of PI 4-kinase (PI4Ks) have been isolated and functionally characterized. The alpha-type PI4Ks (approximately 220 kDa) contain a PH domain, which is lacking in beta-type PI4Ks (approximately 120 kDa). Beta-type PI4Ks, exemplified by Arabidopsis AtPI4Kbeta and rice OsPI4K2, contain a highly charged repetitive segment designated PPC (Plant PI4K Charged) region, which is an unique domain only found in plant beta-type PI4Ks at present. The PPC region has a length of approximately 300 amino acids and harboring 11 (AtPI4Kbeta) and 14 (OsPI4K2) repeats, respectively, of a 20-aa motif. Studies employing a modified yeast-based "Sequence of Membrane-Targeting Detection" system demonstrate that the PPC(OsPI4K2) region, as well as the former 8 and latter 6 repetitive motifs within the PPC region, are able to target fusion proteins to the plasma membrane. Further detection on the transiently expressed GFP fusion proteins in onion epidermal cells showed that the PPC(OsPI4K2) region alone, as well as the region containing repetitive motifs 1-8, was able to direct GFP to the plasma membrane, while the regions containing less repetitive motifs, i.e. 6, 4, 2 or single motif(s) led to predominantly intracellular localization. Agrobacterium-mediated transient expression of PPC-GFP fusion protein further confirms the membrane-targeting capacities of PPC region. In addition, the predominant plasma membrane localization of AtPI4Kbeta was mediated by the PPC region. Recombinant PPC peptide, expressed in E. coli, strongly binds phosphatidic acid, PI and PI4P, but not phosphatidylcholine, PI5P, or PI(4,5)P2 in vitro, providing insights into potential mechanisms for regulating sub-cellular localization and lipid binding for the plant beta-type PI4Ks.

1-Phosphatidylinositol 4-Kinase↗

PubMed2006

MORN motifs in plant PIPKs are involved in the regulation of subcellular localization and phospholipid binding.

Multiple repeats of membrane occupation and recognition nexus (MORN) motifs were detected in plant phosphatidylinositl monophosphate kinase (PIPK), a key enzyme in PI-signaling pathway. Structural analysis indicates that all the MORN motifs (with varied numbers at ranges of 7-9), which shared high homologies to those of animal ones, were located at N-terminus and sequentially arranged, except those of OsPIPK1 and AtPIPK7, in which the last MORN motif was separated others by an approximately 100 amino-acid "island" region, revealing the presence of two kinds of MORN arrangements in plant PIPKs. Through employing a yeast-based SMET (sequence of membrane-targeting) system, the MORN motifs were shown being able to target the fusion proteins to cell plasma membrane, which were further confirmed by expression of fused MORN-GFP proteins. Further detailed analysis via deletion studies indicated the MORN motifs in OsPIPK1, together with the 104 amino-acid "island" region are involved in the regulation of differential subcellular localization, i.e. plasma membrane or nucleus, of the fused proteins. Fat Western blot analysis of the recombinant MORN polypeptide, expressed in Escherichia coli, showed that MORN motifs could strongly bind to PA and relatively slightly to PI4P and PI(4,5)P2. These results provide informative hints on mechanisms of subcellular localization, as well as regulation of substrate binding, of plant PIPKs.

Amino Acid Motifs↗

PubMed2006

[Multi-slice spiral CT imaging in the post-operative assessment of cochlear implanted electrode].

OBJECTIVE: To evaluate the usefulness of multi-slice spiral CT (MSCT) in the post-operative assessment of cochlear implanted electrode. METHODS: Twenty-three cochlear implant recipients were enrolled in this study. All patients were examined with a SOMATOM Sensation 16-slice CT scanner (Siemens) using the following parameters: 120 kV, 100 mAs, 0. 75 mm collimation, 1 mm reconstruction slice thickness and increment, a pitch factor of 1, and a FOV of 100 mm. The axial images of interested ears were reconstructed with 0.1 mm increment and a FOV of 50 mm, and then volume rendering technique (VRT) reconstruction were done on the work station. RESULTS: The electrode arrays were detected on axial CT images. Both inner ear and electrode array could be displayed on one image simultaneously. VRT provided an intuitionistic view of the relationship between electrode array and cochlea VRT showed the number of the electrode array in 20 patients implanted with Combi 40 + standard electrode array and demonstrated the shape, position, and insertion depth. The electrode array number determined by VRT was in accordance with the surgical findings in 18 patients, and was underestimated in two patients. In 3 patients with Combi 40 + compressed electrode array, only 4 to 5 electrodes arrays were clearly identified and others were not observed. CONCLUSION: MSCT with VRT can provide useful three-dimensional information of the electrode array and indicate the exact relationship between electrode array and cochlea.

Adolescent↗

PubMed2006

[Analysis of changes about hsbp1, hsf1, hsf2 AND hsp70's expression levels in rat's regenerating liver].

Heat shock factor binding protein 1 (HSBP1), a recently discovered protein, weakens and blocks transcription of the heat shock protein 70 (HSP70) gene when binding to HSF1, but HSBP1 can promote cell growth, cell development and cell differentiation when binding to HSF2. Partial hepatectomy (PH) in rat creates injury stimulation and induces liver regeneration. How does hsbp1 coordinate two processes sequently is extremely interesting. This paper, based on cloning the full-length cDNA of hsbpl in rat, applied in situ hybridration and Rat Genome 230 2.0 Array to analyze hsbp1, hsf1, hsf2 and hsp70 expression in liver after PH and sham-operation. The results indicated that the hsbp1 expression level was down-regulated meaningfully at 0.5-2h and up-regulated meaningfully at 8-16h after sham-operation, while hsf2 expression level did not meaningfully change at 0-144h after sham-operation. hsbp1 expression level was up-regulated meaningfully at 6h and 66-144h,and hsf1 at 8-16h, hsf2 at 2-16h, hsp70 at 0.5-24h after PH. Our data suggested that up-regulated expression of the hsp70 at 0.5-12h after sham-operation was controlled by intracellular HSF1, and then controlled by hsbp1 down-regulated at 0.5-2h and hsf1 up-regulated at 8-16h. In the early phase of liver regeneration in rats, hsbp1 and hsf2 expression levels were up-regulated, which promoted cell proliferation through HSBP1 and HSF2 up-regulating,upa activating,c-jun enhancing, intracellular matrix (ECM) degradation, activating the hepatocyte-like growth factor (HGF) etc. In the late phase of liver regeneration (66-144h), hsbp1 expression level was up-regulated, which promoted reconstruction of liver structure and recovery of liver function through HSBP1 inhibiting hsp70 expression, up-regulating genes related to growth, development, differentiation. In conclusion, down-regulating of hsbp1 contributed to interaction between HSF1 and HSE,increased hsp70 expression and enhanced anti-injured capacity of liver and rats. HSBP1 and HSF2 activated the genes related to growth, development, differentiation and then promoted liver regeneration in rats.

Animals↗

PubMed2006

[Determination of trace germanium by HG-ICP and study on the medium influence].

A method to determine the content of trace germanium by hydride generation inductively coupled plasma atomic emission spectrometry was established. The influences of different acidic medium, concentration of NaBH4 and other concomitant elements are examined systemically. The optimal analytical conditions were discussed and examined. The detection limit is 0.2 ng x mL(-1) and the precision is 0.9%. The value of germanium content detected in environmental reference material agrees with the certified value. The medium influence on determining trace germanium was studied in detail.

English Abstract↗