Spectrophotometric Determination of Antimony.

Matulis, R. M.; Guyon, John C.

doi:10.1021/ac60230a026

Cited by 13 publications

(14 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…15 In fact, it has been reported that the most effective p K a shift in water arises from competition between hydrophobic and hydrophilic species 16. Such p K a shifts as a result of variation in hydrophobicity have also been described for fatty acids,17 aliphatic amines,18 and peptide hydrogels,19 as well as for thermoresponsive ionic polymers, such as poly(dimethylaminoethyl methacrylate) (co)polymers20, 21 and ionically modified PNIPAAm 22–24. Thermoresponsive ionic polymers have also been demonstrated to enable the temperature‐controlled absorption of carbon dioxide 25.…”

Section: Methodsmentioning

confidence: 98%

Reversible Calcium(II)‐Ion Binding through an Apparent pK_a Shift of Thermosensitive Block‐Copolymer Micelles

et al. 2015

View full text Add to dashboard Cite

There is an increasing need for smart materials capable of removing multivalent ions from aqueous streams without the inconvenience of brine regeneration as in ion-exchange processes. Herein, we present a thermoresponsive micellar system consisting of polystyrene-poly(methoxy diethyleneglycol acrylate) block copolymer surfactants modified with carboxylic acid end groups (PS-PMDEGA-COOH) that can be used to switch between the adsorption and desorption of divalent calcium(II) cations by a mild temperature trigger, thus providing a new type of thermoregenerable ion-adsorbing materials. The switch of calcium(II)-binding capacity is demonstrated to result from a shift in the pKa value of the carboxylic acid groups by the collapse and redissolution of the PMDEGA block and the associated change in local polarity.

show abstract

Section: Methodsmentioning

confidence: 98%

Reversible Calcium(II)‐Ion Binding through an Apparent pK_a Shift of Thermosensitive Block‐Copolymer Micelles

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Here, to demonstrate the main features of the technique, we will study the construction of an e¡ective three-particle operator in the coupled form. Such an operator appears in the second-order erturbation theory and it is associated with diagram 7 A 1 (see Fig. 7): In (26) i j C u j ji H t represents the matrix element of the scalar two-particle operator…”

Section: The Advantages Of the Graphical Technique Appear In The Case...mentioning

confidence: 99%

“…; 27 and e i denotes the single-particle eigenvalue associated with the orbital i j i. The diagram 7 A 1 is generated in the diagrammatic expansion when, in the product of two diagrams of the type 6 A 1 , a pair of creation and annihilation operators is contracted [15]. In the case considered, the contraction is represented by the directed electronic line t. The procedure for the construction of the spin^angular diagram 7 A 2 of the three-particle operator determined by ( 27) is described by the following rules:…”

Section: The Advantages Of the Graphical Technique Appear In The Case...mentioning

confidence: 99%

See 1 more Smart Citation

Graphical Method of Evaluation of Matrix Elements in the Second Quantization Representation

Merkelis

2001

Phys. Scr.

View full text Add to dashboard Cite

A correlation velocity log (CVL) is an acoustic navigation aid that estimates the velocity of a maritime vehicle using a transmitter and a receiving array. The CVL discussed here operates by calculating the correlation coefficient between the echoes from a pair of consecutive acoustic pulses transmitted towards the seafloor, across all combinations of receiver pairings in the array. A correlation surface is constructed by plotting the correlation coefficients versus the spatial separation vector of all the receiver pairings. The coordinates of the peak of this surface provide an estimate of the velocity vector of the vessel. However, the correlation coefficient surface exhibits high variance within a modest distance from the peak position, and individual datasets tend to be asymmetric about the peak position. Since each dataset consists of a sparsely sampled set of discrete measurements, the variance makes the task of peak estimation very challenging. This paper outlines the operating principles of CVLs and describes peak-finding techniques that are used to improve the accuracy and precision of the instrument. Three peak estimation techniques are considered, namely the highest point, and fitting of an axisymmetric quadratic model using either least squares or a nonlinear implementation of maximum likelihood estimation. It is shown that the maximum likelihood approach offers some advantages when the peak is controlled to lie near the centre of the receiver array, but the advantages are small compared to the additional computational load required.

show abstract

“…The antimony is complexed with an organic reagent such as Brilliant Green (1), methyl violet (2), phenylfluorone (3), or Rhodamine B (4), and the colored complex is extracted into an organic solvent where its absorbance can be measured. The use of Pyrocatechin Violet in a sensitive photometric determination has been reported (5), and a method based on the enhancement of the absorbance of a molybdenum blue has been published (6). Neither of these two methods requires an extraction.…”

mentioning

confidence: 99%

Determination of traces of antimony by single sweep polarography

Toren¹

1968

Anal. Chem.

View full text Add to dashboard Cite

the fusion flux, cupel, and silver bead. The sums of the measured activities ranged from 97 to 103% of the standards. They differed from 100% because of the standard deviation associated with the level of 198Au activity in the silver bead. The crucibles were not examined for activity. Quartz was used to simulate the rock sample but this material contained negligible quantities of gold. The results indicate that a 97% or better recovery may be expected if 2 mg or more of silver are used during cupellation, a finding not significantly different from that reported by Fulton (15) and Coxon et al. ( 16) for larger amounts of gold. Since the recovery of gold is close to 100% and the standards, blanks, and samples are carried through the same procedure, no yield correction was made.Evaluation of the Gold Blank. Preliminary experiments indicated that the detection limit would be determined by the magnitude and reproducibility of the gold blank. The primary sources of gold contamination were the reagents used for the fire-assay flux and the clay crucibles used to fuse the sample. The contribution from both sources was about equal but varied considerably. The reagent blank was lowered by performing a preliminary fire-assay fusion on a modified flux yielding a flux composition close to that desired for the fire assay of the samples. The composition of a single charge of flux, before purification, is 100 grams of PbO, 25 grams of Na2C03, 5 grams of Na2B407, and 3 grams of flour. After purification, the composition is equivalent to 60 grams of PbO, 25 grams of Na2COs, 5 grams of Na2B407, and 0 gram of flour. The flux described here was satisfactory for most silicate rocks. If a sample requires a different flux composition, then adjustment should be made prior to purification.The clay crucibles, which are subjected to varying degrees of attack, were replaced by alumina crucibles. The attack on the alumina crucibles is considerably less and they can be re-used.The results of measurements on the gold blank from both the unpurified flux and two separately prepared portions of purified flux are shown in Table II. Sigma is the standard deviation of the average for the series of runs on each sample. If the limit of detection is defined as three times the standard deviation of the blank, then this technique should be able to detect 1.5 ng of gold or 0.1 ppb of gold in a 15-gram sample.Measurement of Gold in W-l. The procedure was tested on the U. S. Geological Survey's standard diabase, W-l, for which data have also been obtained by conventional neutron activation analysis (J, 17). This standard rock is supplied in bottles containing approximately 50 grams. Since 25-gram portions were used, the samples were not mixed nor quartered.The results, shown in Table III, indicate good agreement between these two quite different techniques. ACKNOWLEDGMENTWe thank L. A. Harris and other members of the nuclear reactor staff, Naval Research Laboratory, Washington, D. C., for help in irradiating the lead buttons.

show abstract

Spectrophotometric Determination of Antimony.

Cited by 13 publications

References 22 publications

Reversible Calcium(II)‐Ion Binding through an Apparent pK_a Shift of Thermosensitive Block‐Copolymer Micelles

Reversible Calcium(II)‐Ion Binding through an Apparent pK_a Shift of Thermosensitive Block‐Copolymer Micelles

Graphical Method of Evaluation of Matrix Elements in the Second Quantization Representation

Determination of traces of antimony by single sweep polarography

Contact Info

Product

Resources

About

Spectrophotometric Determination of Antimony.

Cited by 13 publications

References 22 publications

Reversible Calcium(II)‐Ion Binding through an Apparent pKa Shift of Thermosensitive Block‐Copolymer Micelles

Reversible Calcium(II)‐Ion Binding through an Apparent pKa Shift of Thermosensitive Block‐Copolymer Micelles

Graphical Method of Evaluation of Matrix Elements in the Second Quantization Representation

Determination of traces of antimony by single sweep polarography

Contact Info

Product

Resources

About

Reversible Calcium(II)‐Ion Binding through an Apparent pK_a Shift of Thermosensitive Block‐Copolymer Micelles

Reversible Calcium(II)‐Ion Binding through an Apparent pK_a Shift of Thermosensitive Block‐Copolymer Micelles