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S Hann

Publications and source records attributed to S Hann.

13 recordsLinked to original sources
PubMed2004

Novel separation method for highly sensitive speciation of cancerostatic platinum compounds by HPLC-ICP-MS.

A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method is presented for analysis of cisplatin, monoaquacisplatin, diaquacisplatin, carboplatin, and oxaliplatin in biological and environmental samples. Chromatographic separation was achieved on pentafluorophenylpropyl-functionalized silica gel. For cisplatin, carboplatin, and oxaliplatin limits of detection of 0.09, 0.10, and 0.15 microg L(-1), respectively, were calculated at m/z 194, using aqueous standard solutions. (3 microL injection volume). The method was utilized for model experiments studying the stability of carboplatin and oxaliplatin at different chloride concentrations simulating wastewater and surface water conditions. It was found that a high fraction of carboplatin is stable in ultrapure water and in solutions containing 1.5 mol L(-1) Cl-, whereas oxaliplatin degradation was increased by increasing the chloride concentration. In order to support the assessment of oxaliplatin eco-toxicology, the method was tested for speciation of patient urine. The urine sample contained more than 17 different reaction products, which demonstrates the extensive biotransformation of the compound. In a second step of the study the method was successfully evaluated for monitoring cancerostatic platinum compounds in hospital waste water.

Antineoplastic Agents↗
PubMed2003

Platinum determination by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) in different matrices relevant to human biomonitoring.

The analytical challenges of Pt determination by ICP-SFMS posed by different human tissues and fluids have been critically assessed. Investigated samples were (1) urine, (2) serum of cancer patients sampled during chemotherapy with carboplatin, (3) microdialysates (20 micro L sample volume) collected from tumor and non-tumor tissue, and, finally-for the first time-(4) human lung tissue to study background concentrations of inhaled platinum. Sample preparation involved microwave digestion and open vessel treatment or simple dilution (microdialysates). Depending on the sample preparation and introduction systems used (microconcentric nebulization, ultrasonic nebulization with and without membrane desolvation) excellent procedural detection limits (3s criterion) of 0.35 pg g(-1) for urine, 420 pg g(-1) for serum, 400 pg g(-1) for lung tissue and 13 pg g(-1) for microdialysates could be obtained. Ultratrace concentrations of 1-40 pg g(-1), and 1000-3000 pg g(-1) were measured in urine and human lung tissue, respectively, as typical for samples in environmental studies. Quantification was carried out by IDMS and standard addition in the case of urine samples. Internal standardization could not correct for non-spectral interferences in external calibration. In the serum and microdialysates of patients during chemotherapy with carboplatin, elevated Pt levels ranging between 0.01 and 10 micro g g(-1) were determined by external calibration ((195)Pt isotope). For all investigated samples spectral interferences could be excluded by following different strategies. High-resolution control measurements ((194)Pt, (195)Pt) were performed in the case of elevated Pt levels, i.e. for microdialysates and serum samples. An Hf/Pt ratio of 0.4 was determined in human lung samples. An HfO formation ratio of 0.2% was assessed for standard solutions at the present experimental conditions, revealing that the contribution of (179)Hf(16)O, (178)Hf(17)O, (177)Hf(18)O to the (195)Pt isotope signal used for quantification was not significant.

Blood Chemical Analysis↗
PubMed2001

HPIC-UV-ICP-SFMS study of the interaction of cisplatin with guanosine monophosphate.

Interaction of cis-[Pt(NH3)2Cl2] (cisplatin) with 5'-guanosine monophosphate (5'-GMP) has been investigated for the first time by on-line coupling of high performance ion chromatography (HPIC) to inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The time-dependent reaction course of the cisplatin-5'-GMP system was followed after incubation under simulated physiological conditions by monitoring the decrease in the concentration of 5'-GMP and the increase in the concentration of formed adducts, on the basis of speciation analysis. Because of the two-step mechanism an intermediate mono adduct was observed together with the major product, the bis adduct cis-[Pt(NH3)2(GMP)2]2-. The data obtained correlated well with those from earlier studies employing orthogonal techniques such as capillary electrophoresis (CE). Furthermore, HPIC-ICP-SFMS provided unambiguous stoichiometric information about the major GMP-adduct. For this purpose the platinum-to-phosphorus ratio was determined by simultaneously measuring 31P and 195Pt. To separate significant interferences from 15N16O+, 14N16O1H+, 12C18O1H+, and 13C17O1H+ on 31P, high-mass resolution (m/deltam = 4,500) proved to be mandatory. The P/Pt signal ratio of 2/1 obtained corresponds to the molar ratio in the bis adduct cis-[Pt(NH3)2(GMP)2]2-.

Antineoplastic Agents↗
PubMed2001

Analysis of Ir in Köfelsit rocks by inductively coupled plasma-sector-field mass spectrometry (ICP-SFMS).

Three different analytical strategies have been evaluated for the quantification of Ir in geological samples. Glassy rock samples from Köfels and reference material WGB-1 were analyzed directly by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) at mass resolution 400 using membrane desolvation and at mass resolution 9500 without membrane desolvation. Matrix separation by anion-exchange pre-concentration was also investigated. The ultrasonic nebulizer USN6000AT+ (Cetac Technologies, Omaha, NE, USA) incorporating a membrane desolvation unit was used as the sample-introduction system. Sample preparation involved complete microwave-assisted acid digestion of the silicate matrix with HNO3-HCl-HF. The results obtained by the three methods of quantification were in good agreement, showing that oxide-type interferences were effectively eliminated solely by membrane desolvation. The limits of detection were 6 pg g for low resolution measurement with use of the membrane, 15 pg g(-1) at a mass resolution of 9500, and 59 pg g(-1) for the ion-exchange procedure. The ultimate precision obtained for the Köfelsit Ir data was, however, compromised by the small sample intake (0.3 g), because of the inhomogeneous distribution of Ir in geological samples.

Journal Article↗
PubMed2000

SI-traceable certification of Cu, Cr, Cd and Pb in sediment and fly ash candidate reference materials.

Many fields in environmental analytical chemistry deal with very low limits and thresholds as set by governmental legislations or transnational regulations. The need for the accuracy, comparability and traceability of analytical measurements in environmental analytical chemistry has significantly increased and total uncertainties are even asked for by accreditation bodies of environmental laboratories. This paper addresses achieving these goals to guarantee accuracy, quality control, quality assurance or validation of a method by means of certified reference materials. The assessment of analytical results in certified reference materials must be as accurate as possible and every single step has to be fully evaluated. This paper presents the SI-traceable certification of Cu, Cr, Cd and Pb contents in geological and environmentally relevant matrices (three sediments and one fly ash sample). Certification was achieved using isotope dilution (ID) ICPMS as a primary method of measurement. In order to reduce significantly the number of analytical steps and intermediate samples a multiple spiking approach was developed. The full methodology is documented and total uncertainty budgets are calculated for all certified values. A non-element specific sample digestion process was optimised. All wet chemical digestion methods examined resulted in a more or less pronounced amount of precipitate. It is demonstrated that these precipitates originate mainly from secondary formation of fluorides (essentially CaF2) and that their formation takes place after isotopic equilibration. The contribution to the total uncertainty of the final values resulting from the formation of such precipitates was in general < 0.1% for all investigated elements. Other sources of uncertainty scrutinised included the moisture content determination, procedural blank determination, cross-contamination from the different spike materials, correction for spectral interferences, instrumental background and deadtime effects, as well as the use of either certified values or IUPAC data in the IDMS equation. The average elemental content in the sediment samples was 30-130 micrograms g-1 for Pb, 0.5-3 micrograms g-1 for Cd and 50-70 micrograms g-1 for Cu. Cr was measured in one sample and was about 60 micrograms g-1. The concentrations in the fly ash sample were up to 2 orders of magnitude higher. Expanded uncertainty for the investigated elements was about 3% (coverae factor k = 2) except for Cr, (measured by high resolution ICPMS), for which the expanded uncertainty was about 7% (k = 2).

Air Pollution↗
PubMed1998

Rocuronium versus succinylcholine: are they equally effective during rapid-sequence induction of anesthesia?

UNLABELLED: The purpose of our study was to assess the onset and quality of muscle paralysis and intubation conditions with succinylcholine (Sch) or rocuronium (Roc) during rapid-sequence induction. Patients were randomly assigned to receive thiopental (5 mg/kg) and Sch (1.5 mg/kg) or thiopental (5 mg/kg) and Roc (1.2 mg/kg). The anesthesiologists performing the endotracheal intubation were blinded by standing with their back to the patient. Thirty seconds after drug administration, laryngoscopy was performed. Intubating conditions were scored, the clinical onset of apnea was noted, and a train-of-four monitor recorded data. All patients were ASA physical status I-III and scheduled for emergency procedures; both groups were demographically similar. Thirteen patients received Roc and 13 received Sch. There was no significant difference between the two groups in the number of patients receiving excellent intubating scores (P = 0.41) or in the combined number of patients receiving good and excellent scores (P = 1.0). There was no significant difference in time of onset of apnea for Sch (22+/-13 s) versus Roc (16+/-8s). The return of the first twitch response was significantly faster with Sch (5.05+/-2.5 min) compared with Roc (17.3+/-21.7 min) (P = 0.0001). IMPLICATIONS: In pediatric patients scheduled for emergency surgery, thiopental 5 mg/kg and rocuronium 1.2 mg/kg provided conditions for the completion of intubation in <60 s comparable to those provided by thiopental 5 mg/kg and succinylcholine 1.5 mg/kg. We conclude that rocuronium is a reasonable substitute for succinylcholine in children for rapid-sequence intubation when a rapid return to spontaneous respiration is not desired.

Adolescent↗
PubMed1985

Zinc deficiency: a problem with preterm breast milk.

We report a breast-fed preterm infant (31 weeks gestation) who developed nutritional zinc deficiency 13 weeks post delivery. Serial samples of his mothers breast milk from early lactation (2 weeks post delivery) contained very low zinc concentrations, although her serum zinc and sweat zinc concentrations were normal. Following the birth of her second baby at 38 weeks gestation, her breast milk contained normal amounts of zinc. We conclude that the low breast milk zinc values obtained following the first pregnancy may have been due to immaturity of the milk. Units that feed very low birth-weight babies preterm milk should check its zinc concentration or at least have a high index of suspicion for this nutritional deficiency.

Breast Feeding↗
PubMed1976

Interactions of Pseudomonas aeruginosa with immunoglobulins and complement in sputum.

The interactions of Pseudomonas aeruginosa with humoral factors in the sputum of patients with cystic fibrosis were investigated by using an indirect immunofluorescent technique. Fluorescein-conjugated, monovalent antiserum specific to heavy chains of human immunoglobulin A (IgA), IgG, or IgM and to complement C3 were used. All strains of P. aeruginosa recovered from the sputum specimens of patients with cystic fibrosis were found to be coated with antibodies of IgA, IgG, and IgM classes and with C3. The specificity of the antibody coating was determined. The fluorescence was most intense with IgA and was followed in intensity by IgG, IgM, and C3. No difference was noted between rough and mucoid strains of P. aeruginosa. When the subcultured P. aeruginosa was incubated with the sputum eluates, a similar pattern of fluorescence was demonstrated, indicating that these humoral factors are present in the sputum and that the coating process can take place in the lower respiratory tract of the patients. By single radial immunodiffusion, significant quantities of the humoral factors in the sputum eluates were detected. These findings suggest that P. aeruginosa is opsonized in sputum of patients with cystic fibrosis.

Adolescent↗
PubMed1976

Subpopulations of peripheral lymphocytes in juvenile diabetes.

Subpopulations of peripheral lymphocytes were studied in 26 children with insulin-treated juvenile diabetes and in 27 control children of comparable age. T-lymphocytes were quantitated by spontaneous rosette-formation with sheep erythrocytes and B-lymphocytes by indirect immunofluorescence with the use of monovalent, fluorescein-labeled rabbit antiserum specific to the heavy chains of human IgG IgM, or IgA. No significant quantitative difference in subpopulations of the peripheral lymphocytes, T-cells, and B-cells with IgG, IgA, or IgM markers found between children with juvenile diabetes and the control group, although the B-lymphocytes with IgG or IgA markers tended to be higher and those with IgM markers lower in the diabetic than in the control group.

Adolescent↗