共查询到20条相似文献,搜索用时 21 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
The oxidation of glycolaldehyde with hexaquomanganese(III) ions in a noncomplexing perchloric acid medium was studied. The optimum conditions have been found for analytical use of the reaction. The recommended procedure is based on the oxidation of the test substance with the oxidant in the absence of atmospheric oxygen and back-titration of the unconsumed reagent with ferrous sulfate.
相似文献
2. Accuracy and Reproducibility of the Determination of Glycolaldehyde with Hexaquomanganese(III) Ions in a Noncomplexing Perchloric Acid Medium
Taken (μg) | Found (μg)a | Standard deviation (μg) |
751 | 748 | 12 |
1501 | 1485 | 15 |
2252 | 2192 | 7 |
- a
- The values are the average of seven determinations, from which the standard deviation value was calculated.
11.
Spectrophotometric investigation of the deep blue colored, water-soluble complex of
1. Stability constant and free energy of formation of Cu-NMS complex at 30 ± 1 °C
Method | ΔF (Kcal/mole) | ||||
Mukherji and Dey (4) | 4.11 | ?5.70 | |||
Subhrana and Raghavrao (6) | 4.80 | ?6.66 |
Hydrochloric acid | 4 — 8M | ||||
Lead | 0 — 0.03M | ||||
Antimony | 0 — 0.002M |
Time (min) | 0 | 5 | 10 | 30 | 60 |
Consumption of Mn(III) (mol/mol) | 2.00 | 1.99 | 2.00 | 2.01 | 2.00 |
Sample | Determinations | Mean (μg) | SD (μg) | |
Whole blood | 10 | 1004 | 21 | |
Blood plasma | 10 | 543 | 4 | |
TCA extracts | 10 | 24 | 2 | |
Urine (totals) | 10 | 598 | 31 | |
Urine (inorganic S) | 10 | 374.4 | 19 |
SO2 (ppm) | ?HgCl2a | ?HgBr2 | ?Hg(Ac)2b | ?Hg(SCN)2 |
2.0 | 12,500 | 10,000 | 10,000 | 9,200 |
4.0 | 12,500 | 11,500 | 10,000 | 9,000 |
6.0 | 12,500 | 11,500 | 10,000 | 9,200 |
8.0 | 12,000 | 11,000 | 10,500 | 9,800 |
- a
- Molar absorptivity based on sulfite ion at 230 nm. Solution was 6.86 buffer.
- b
- Mercuric acetate solutions seemed to be somewhat unstable. absorptivity of about 25,000. The absorbance is linear over a range of approximately 0.5–5.0 ppm as SO2. Covalent mercury(II) compounds form a complex with sulfite, Hg(SO3)22?, which absorbs at 230 nm and shows a linear response over a range of 1–8 ppm as SO2.
16.
A kinetic method is described for the determination of trace amounts of magnesium in the presence of calcium. The procedure is based on the inhibition of the manganese(II) catalyzed aerial oxidation of 1,4-dihydroxyphthalimide dithiosemicarbazone reaction by
相似文献
2. Effect of Transition Metalsa
Transition metal | Concentration (M) | Percentage inhibition | Mg(II) found (×l05M) |
Fe(II) | 3.6.10?5 | 54.1 | 4.62 |
Fe(III) | 3.6.10?5 | 47.8 | 4.48 |
Co(II) | 3.4.10?5 | 50.0 | 4.53 |
Ni(II) | 3.4.10?5 | 50.0 | 4.53 |
Cu(II) | 3.1.10?5 | 52.0 | 4.56 |
Zn(II) | 3.0.10?5 | 54.1 | 4.62 |
Cd(II) | 1.7.10?5 | 52.0 | 4.56 |
Hg(II) | 9.9.10?6 | 45.8 | 4.44 |
Sn(II) | 2.1.10?6 | 50.0 | 4.52 |
Pb(II) | 1.2.10?6 | 54.1 | 4.62 |
- a
- Conditions: 4.53.10?5M Mg(II), 35 ng Mn ml?1, 0.429 M ammonia, 1.6.10?4M OH-PDT.
3. Determination of Magnesium in Natural Waters
Mg(II) found (M)b | |||
Natural water | Ca(II) presenta | Atomic absorption | |
sample | M | Kinetic absorption | method |
Commercial | 3.45 · 10?4 | 1.65 · 10?3 | 1.74 · 10?3 |
Commercial | 5.46 · 10?4 | 1.57 · 10?4 | 1.81 · 10?4 |
Untreated | 6.13 · 10?4 | 2.16 · 10?4 | 2.40 · 10?4 |
Treated | 4.95 · 10?4 | 1.93 · 10?4 | 2.17 · 10?4 |
- a
- EDTA titration less the magnesium.
- b
- Average of three separate determinations. traces of magnesium(II). The reaction is followed spectrophotometrically by measuring the rate of change in absorbance at 594 nm. The calibration graph (percentage inhibition vs magnesium concentration) is linear in the range 329–535 · 10?5M with an accuracy and precision of 1.2%. The method has been applied to the determination of magnesium in natural waters at low concentrations.
17.
Cadmium ions react with the collector, ethylhexadecyldimethylammonium bromide (EHDABr), to form a surface-active sublate which can be removed from aqueous bromide
相似文献
a. Effect of Foreign Metal Ions on the Flotation of Cadmiuma
Foreign ion | Foreign ion concentration (M) (×10?5) | Foreign ion removed (%) | Cadmium removed (%) |
None | 99.21 | ||
Zn2+ | 6.11 | 0.06 | 98.41 |
Cu2+ | 6.29 | 3.64 | 97.80 |
Pb2+ | 3.86 | 4.80 | 91.78 |
Cr6+ | 7.69 | 30.75 | 99.07 solutions by ion flotation. A typical ion flotation procedure involves passing air through a 250-ml solution containing 5 ppm Cd2+, 0.05 M Br?1, and 1.7 × l0?3M EHDABr at a flow rate of 40 ml/min for 1 hr. The procedure was simple and efficient. Chromium, copper, and zinc ions do not interfere under the experimental conditions. |
- a
- Cd2+, 4.46 × 10?5M; EHDABr, 4.25 × 10?4; Br?, 5 × 10?2M; flow rate, 40 ml/min; time, 60 min.
18.
A sensitive spectrofluorimetric procedure with rhodamine B in the presence of aluminum chloride is given for determining submicrogram and microgram quantities of thallium in silicate rocks. Samples are decomposed with a mixture of hydrofluoric and nitric acids and then treated with hydrochloric acid. Thallium is extracted as its dithizonate with chloroform from an alkaline medium containing ascorbate, citrate, and cyanide and then back-extracted with dilute nitric acid. After destruction of the organic matter and treatment with bromine, hydrochloric acid, aluminum chloride, and rhodamine B, the
相似文献
T001. Determination of thallium in U.S. Geological Survey standard rocks by different laboratories
Thallium (p.p.m.) | Method | Ref. | |
G-1 | W-1 | ||
1.06 | 0.102 | Neutron activation analysis | 1 |
1.08 | 0.121, 0.116 | Neutron activation analysis | 2 |
1.3 | 0.17 | Neutron activation analysis | 3 |
1.3 | 0.11 | Spectrographic | 4 |
0.105–0.110 | Flameless atomic absorption spectroscopy | 5 | |
1.3a | 0.13a | 19 | |
1.24b | 0.110b | 20 | |
1.09 ± 0.01 | 0.110 ± 0.005 | Spectrofluorimetric | Present method |
- a
- Values given by Fleischer.
- b
- Average value given by Flanagan. fluorescence intensity of the benzene-extracted rhodamine B chlorothallate is measured. The limit of determination is approximately 0.01 p.p.m. for a 1.0-g sample. The thallium contents of U.S. Geological Survey standard rocks G-1 and W-1 were found to be 1.09 ± 0.01 and 0.110 ± 0.005 p.p.m., respectively.
19.
The acidic dissociation constants of three vic-dioximes have been determined from spectrophotometric data. The results may be summarized as follows:
pK1 | pK2 | |
2,3-butanedionedioxime | 10.6 ± 0.1 | 11.9 ± 0.3 |
1,2-cyclohexanedionedioxime | 10.6 ± 0.2 | 12.4 ± 0.5 |
1,2-cycloheptanedionedioxime | 10.7 ± 0.2 | 12.3 ± 0.5 |
Cell type | Applications |
Human polymorphonuclear leukocytes | (1) Detection of bactericidal defects, particularly chronic granulomatous disease |
(2) Detection of host opsonic defects (both immunoglobulin and complement ?C3b opsonic defects). | |
(3) Analysis of drug effects on host cellular and opsonic defenses (9,11). | |
(4) Characterization of bacteria or other particulate matter in terms of ability to generate opsonic activity and/or be ingested by phagocytic cells (3,7). | |
Alveolar macrophages | (1) Detection of environmental pollutant effects on respiratory defense mechanisms (against both particulate and soluble matter). |
(2) Analysis of drug effects on respiratory defense mechanisms, particularly drugs administered in the treatment of respiratory diseases. |
设为首页 | 免责声明 | 关于勤云 | 加入收藏 |
Copyright©北京勤云科技发展有限公司 京ICP备09084417号 |