首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
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.
2. Accuracy and Reproducibility of the Determination of Glycolaldehyde with Hexaquomanganese(III) Ions in a Noncomplexing Perchloric Acid Medium
Taken (μg)Found (μg)aStandard deviation (μg)
75174812
1501148515
225221927
a
The values are the average of seven determinations, from which the standard deviation value was calculated.
  相似文献   

2.
A simple, rapid, and accurate method for determination of total sulfur and inorganic sulfate in biological materials by barium chloranilate colorimetry is presented. Criteria required
3. Precision of S Determination, Whole Blood, Blood Plasma, TCA Extracts, and Urine
  相似文献   

3.
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
SampleDeterminationsMean (μg)SD (μg)
Whole blood10100421
Blood plasma105434
TCA extracts10242
Urine (totals)1059831
Urine (inorganic S)10374.419
  相似文献   

4.
A polarographic method for the determination of antimony in lead-antimony alloys has been developed. It was found that the interference due to the presence of varying concentrations of lead and hydrochloric acid would be eliminated by the addition of potassium chloride.
t001. The method gave satisfactory results within the range:
MethodlogKsΔF (Kcal/mole)
Mukherji and Dey (4)4.11?5.70
Subhrana and Raghavrao (6)4.80?6.66
  相似文献   

5.
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
2. Effect of Transition Metalsa
Hydrochloric acid4 — 8M
Lead0 — 0.03M
Antimony0 — 0.002M
Transition metalConcentration (M)Percentage inhibitionMg(II) found (×l05M)
Fe(II)3.6.10?554.14.62
Fe(III)3.6.10?547.84.48
Co(II)3.4.10?550.04.53
Ni(II)3.4.10?550.04.53
Cu(II)3.1.10?552.04.56
Zn(II)3.0.10?554.14.62
Cd(II)1.7.10?552.04.56
Hg(II)9.9.10?645.84.44
Sn(II)2.1.10?650.04.52
Pb(II)1.2.10?654.14.62
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 waterCa(II) presentaAtomic absorption
sampleMKinetic absorptionmethod
Commercial3.45 · 10?41.65 · 10?31.74 · 10?3
Commercial5.46 · 10?41.57 · 10?41.81 · 10?4
Untreated6.13 · 10?42.16 · 10?42.40 · 10?4
Treated4.95 · 10?41.93 · 10?42.17 · 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.
  相似文献   

6.
Nitron and tetraphenylarsonium chloride react with a cobaltous salt in the presence of thiocyanate to form blue ion-association complexes, which can be extracted with organic solvents. This fact has been made the basis for the analysis of mixtures of nitrate and perchlorate by difference spectrophotometry. An aliquot of the sample solution is treated with a known excess of tetraphenylarsonium chloride to precipitate perchlorate only. After separating off the precipitate, the excess of reagent is determined in the supernatant liquid as tetraphenylarsonium cobaltothiocyanate and the perchlorate content can be found from a calibration curve. Another aliquot is treated with an excess of nitron to precipitate both anions; the excess of nitron is then determined as nitron
2. Analysis of Nitrate-Perchlorate Mixtures
  相似文献   

7.
The acidic dissociation constants of three vic-dioximes have been determined from spectrophotometric data. The results may be summarized as follows:
PerchlorateNitrate
Taken (μg)Found (μg)Error (%)Taken (μg)Found (μg)Error (%)
400404+ 1.00248250+0.81
4004000.00496492?0.81
4004000.009929920.00
800796?0.502482480.00
600602+0.33248245?1.21
800792?1.25496498+0.40
  相似文献   

8.
In summary, this report describes the conditions under which luminol has been utilized to measure phagocytosis-associated metabolic events in activated human PMNs and rabbit and dog alveolar macrophages. We feel that this system may have wide applicability to both clinical and experimental situations. Some possible applications are shown in the following table.
Potential Applications of Luminol-Amplified Chemiluminescence
pK1pK2
2,3-butanedionedioxime10.6 ± 0.111.9 ± 0.3
1,2-cyclohexanedionedioxime10.6 ± 0.212.4 ± 0.5
1,2-cycloheptanedionedioxime10.7 ± 0.212.3 ± 0.5
  相似文献   

9.
Cobalt ions in aqueous thiocyanate solution react with Aliquat-336-xylene solution to form anion-association complex which is easily extracted into the organic phase. A typical extraction procedure involves extracting a solution which is 10 ppm in cobalt and 0.06 M,
5. Stripping of Cobalt from 2% Aliquat-336-Xylene Solutions
Cell typeApplications
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.
  相似文献   

10.
The Coulometrics Inc. CO2 coulometer has been shown to be an accurate and reliable CO2 measuring device. The coulometric efficiency is essentially 100%. This means that the method can be considered as a standard reference method for CO2. As with a CO2 absorption tube, certain potential interferences must be considered, however, the removal of these interferences is well documented in the literature.The CO2 coulometer has found a variety of applications in the author's
3. effect of flow rate on absorption of CO2 by coulometer
StrippantCobalt stripped (%)
Na2S (M) 1.018.3
2.010.7
Na2SO3 (M) 0.110.7
0.549.6
1.052.9
EDA (%) 2.576.6
NaOH (M) 0.14.1
0.574.1
1.090.8
2.076.8
NH4OH (M) 0.124.1
0.591.8
1.097.5
2.099.9
EDTA (M) 0.02>99.9
0.05>99.9
0.1>99.9
EDTA (%) 0.1>99.9
0.5>99.9
1.0>99.9
  相似文献   

11.
Rotational spectra have been assigned for four isotopic species of the linear HCN dimer in the vibrational ground state. The spectroscopic constants are
CaCO3 (mg)C (mg)Flow rate (cm3/min)C found (mg)C (%)
27.9893.3591003.366912.03
28.6043.4322003.434312.00
29.2593.5113003.514912.01
33.8084.0574004.038111.94
5.6290.6755000.676012.01
10.3111.2375001.233711.96
15.6471.8785001.870611.95
35.2144.2265004.198211.92
40.7334.8885004.821211.84
59.6787.1615007.026311.77
30.3863.6467803.594111.83
29.7813.5747803.536111.87
28.1133.37411503.253411.57
  相似文献   

12.
With the help of the Chcvcnard thcrmobalancc the authors have determined the minimum temperatures necessary for quantitatively converting the derivatives of gallium into oxide Ga203.
isotope-B0 (MHz)DJ (kHz)xN1 (MHz)xN2 (MHz)
HC14N-HC14N1745.80973(50)2.133(30)?4.0973(200)?4.4400(190)
HC14N-HC15N1700.30190(30)1.939(40)?4.1059(10)-
HC15N-HC14N1729.92082(20)2.023(30)-?4.4339(6)
HC15N-HC15N1684.28825(25)1.900(30)--
  相似文献   

13.
Cadmium ions react with the collector, ethylhexadecyldimethylammonium bromide (EHDABr), to form a surface-active sublate which can be removed from aqueous bromide
a. Effect of Foreign Metal Ions on the Flotation of Cadmiuma
Hydroxide by ammonium hydroxide408°
Hydroxide by ammonia400°
Hydroxide by urea475°
Hydroxide by aniline546°
Hydroxide by sulpliitc813°
Hydroxide by tannin520°
Cupfcrron745°
Camphoratc478°
Dibromo-oxinate817°
Foreign ionForeign ion concentration (M) (×10?5)Foreign ion removed (%)Cadmium removed (%)
None99.21
Zn2+6.110.0698.41
Cu2+6.293.6497.80
Pb2+3.864.8091.78
Cr6+7.6930.7599.07 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.
  相似文献   

14.
The hydrogen-bonded heterodimer formed between oxetane and hydrogen fluoride is identified and characterised by means of its IR and microwave spectra. The following rotational constants (MHz) and centrifugal distortion constants (kHz) have been derived:
  相似文献   

15.
Two stereoselective routes for the synthesis of trienes having a central cis double bond have been devised. These were employed for the synthesis of (Z)-1-(cyclohexen-1-yl)-1,3-butadiene (1), (Z,E)-1-(cyclohexen-1-yl)-1,3-pentadiene (2), (Z,Z)-1-(cyclohexen-1-yl)-1,3-pentadiene (3), 1,2-divinyleyclohexene (4), (E,Z)-1-phenyl-1,3,5-hexatriene (5), (Z,Z)-1-phenyl-1,3,5-hexatriene (6) and (E,Z)-1-(p-chlorophenyl)-1,3,5-hexatriene (7). Rates of the thermal electrocyclization and activation parameters were measured for these in inert solvents. The results are tabulated below.
ABCΔJΔJK
(CH2)O3?HF92172575.12350.611.3?57.0
(CH2)3O?DF9157(ass)2544.72329.39.9?56
  相似文献   

16.
A direct amperometric titration of copper is described; o-(p-tolylsulfonamido) aniline serves as titrant. The optimum conditions are discussed and the method is applied to the analysis of copper in brass alloys.
t001. IV. Analysis of various samples in which copper was determined (Values given as percentages)
Compoundk1 x 105(sec?1)Temp (°C)ΔH3ΔS3
112·813229?6
212·513229?1
32·617334?5
43·8612525?15
516·014528?8
63·0195
715·014525?18(?)
  相似文献   

17.
Electrical conduction (dc) studies are made with pure and cobalt(II)-doped single crystals of NH4H2PO4 and KH2PO4. The effect of the dopant concentration on the enthalpy for the migration of protons and the enthalpy for the rotation of the H2PO4 group have been studied. It is suggested that proton migration occurs through a synchronous phosphate rotation mechanism. Tritium diffusion studies in KDP and 32PO4 diffusion in ADP crystals have been made. The mechanisms for the conduction and diffusion processes are found to be different in nature. The distribution coefficients of Co(II) dopant in ADP (2.92 × 10?3) and KDP (1.14 × 10?3) are calculated. The following enthalpy values are obtained.
ConstituentsThorn Smith # 30Thorn Smith # 54NBS # 37ENBS # 63C
Cu present59.3084.0469.6180.48
Zn37.811.45227.850.093
Pb0.18.5901.009.35
SnTrace5.7371.009.03
Sb0.52
NiTrace0.530.32
P0.145
S0.060
As0.023
Fe1.220.0040.0013
Al1.15
Mn0.35
Cu found59.0983.6469.68a80.54aaAverage of 3 determinations.
  相似文献   

18.
Sulfite ion reacts with mercury(II) ion in acid solution to form the mercury(I) ion. The reaction is rapid and quantitative. The mercury(I) ion absorbs at 237 nm with a molar
5. Beer's law Data for Sulfite Complexes of Covalent Mercury(II) Compounds
KDP (eV)ADP (eV)
Enthalpy for the migration of protons0.01 ± 0.010.15 ± 0.02
Enthalpy for the rotation of phosphate group0.71 ± 0.010.66 ± 0.01
Enthalpy for T-diffusion0.14 ± 0.01
Enthalpy for 32PO4 diffusion0.24 ± 0.01
SO2 (ppm)?HgCl2a?HgBr2?Hg(Ac)2b?Hg(SCN)2
2.012,50010,00010,0009,200
4.012,50011,50010,0009,000
6.012,50011,50010,0009,200
8.012,00011,00010,5009,800
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.
  相似文献   

19.
The authors discuss several aspects of the chemistry of indium, giving evidence for a hydrate 2ln2O3.H2O and studying in detail the behaviour of indium sulphide heated in air. Compared with that of gallium, the oxinate is particularly stable.Compounds used for the gravimetric determination of indium should be heated to the following temperatures in order to give correct results:
  相似文献   

20.
A potentiometric method is described for the determination of thiosemicarbazones involving the formation of a complex with Ag(I). This method is proposed for thiosemicarbazones of the following carbonyl compounds: salicylaldehyde, p-hydroxybenzaldehyde, benzaldehyde, picolinaldehyde, 6-methylpicolinaldehyde and p-dimethylaminebenzaldehyde. Stability constants of the complexes are determined by Ringbom and Harju's method.
FIG. 2. Variation of pAg + logαPAT (H) + log ([Ag?PAT)]/[PAT])
2. Formation Constants of the Silver-Thiosemicarbazonates
Hydroxide by ammonia345°
Hydroxide by hexamethylene tetramine546°
Hydroxide by cyanate475°
Sulphide94–221°, 320–544°, 690°
Phosphate477°
Luteocobaltic indichloride100–105°
Oxinate100–285°
Diethyldithiocarbamate100–210°
  相似文献   

ThiosemicarbazoneLog Kf
-Benzaldehyde15.5 ± 0.1
-Picolinaldehyde14.0 ± 0.
-6-Methylpicolinaldehyde14.5 ± 0.
-Salicylaldehyde15.7 ± 0.1
-p-Hydroxybenzaldehyde15.6 ± 0.
-p-Dimethylaminebenzaldehyde17.2 ± 0.1
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