Short-chain Amine Research Articles

Detection of antisperm antibody in human serum using a piezoelectric immunosensor based on mixed self-assembled monolayers

A novel piezoelectric immunosensor based on mixed self-assembled monolayers (mixed SAMs) formed by short-chain amine- and carboxyl-terminated thiols has been developed to immobilize antigens onto gold electrodes for detecting antisperm antibody (AsAb) in human serum samples. The properties and the enhanced performance of the affinity biosensor interface based on mixed SAMs are investigated. Most importantly, analytical results of several human serum samples using the developed technique are in satisfactory agreement with those given by the enzyme-linked immunosorbent assay (ELISA) method in the concentration ranging from 32.3 to 300.0 mU/ml. It means the procedure proposed in this paper is likely to have a great potential in research and may play an important clinical role in a few years later.

Synthesis of hexagonal microporous silica and aluminophosphate by supramolecular templating of a short-chain amine

Hexagonal microporous phases of SiO 2 and AlPO 4 with pore sizes in the range intermediate between traditional microporous and mesoporous materials have been prepared, by making use of supramolecular organization of short-chain amine (n-C 6H 12NH 2) template molecules. The pore diameters are around 1.4 nm in both cases. The hexagonal microporous phase of AlPO 4 is formed only in the presence of fluoride ions. The surface area of SiO 2 after removal of the template is 800 m 2 g −1. In the case of AlPO 4, the surface area is 190 m 2 g −1 after removal of 60% of the template.

Aminolysis of 4-nitrophenyl esters of phosphorus acids in reversed micelles of 2-hydroxyethyldimethylpentadecylammonium bromide

The reactions ofn-cetyl- andn-hexylamines with 4-nitrophenyl esters of tetracoordinated phosphorus acids in chloroform in the presence of 2-hydroxyethyldimethylpentadecylammonium bromide and the influence of the latter on the acid—base equilibrium of the bromphenol blue dye (BPB) were studied by the spectrophotometric method. In the presence of reversed micelles of the cationic surfactant, the observed rate constant of aminolysis increases by more than two orders of magnitude. The catalytic efficiency of the micelles increases as the concentration of the long-chain amine decreases and on going from the latter to a short-chain amine. The acid—base equilibrium of BPB in micellar solutions is shifted due to the formation of a complex between the surfactant and the BPB dianion.

Excess heats of tri-n-alkylamines and tetraalkyl tin compounds in linear and branched alkanes: correlations of molecular orientations and steric hindrance effect

Excess heats of the following mixtures of trialkylamines and tetraalkyl tin compounds with branched and linear alkanes have been measured at 25 °C: five trialkylamines NR3 (R = C2H5, C3H7, C4H9, C10H21, C12H25) with six linear alkanes, n-C5, n-C6, n-C8, n-C10, n-C12, n-C16, and three highly branched alkanes, 2,2,4-trimethylpentane, 2,2,4,6,6-pentamethylheptane, and 2,2,4,4,6,8,8-heptamethylnonane (br-C16). Further measurements were carried out on tetrapropyl tin (SnPr4) with n-C8, n-C16, and br-C16.Measurements were made to obtain more information on the heats of disordering of long chain compounds and on an exothermic contribution to the heats coming possibly from the sterically hindered character of one of the components of the mixture. The three short-chain trialkylamines have large heats with the linear long alkanes and small heats with the branched alkanes. On the other hand, the two long-chain trialkylamines have very small heats with linear alkanes and large heats with the branched alkanes. These results are interpreted as indicating no change of liquid or solution 'structure' when two ordered compounds (long alkanes and long-chain amines) are mixed but a change of 'structure' when an ordered compound (long alkane or long-chain amine) is mixed with a non-ordered one (branched alkane or short-chain amine). The heat of disordering of n-hexadecane is obtained with many order breakers and found to depend to some extent on the expansion coefficient of the order breaker. HE values for the series of the shorter NR3 do not vary regularly with molecular weight but are smaller for the propyl (and possibly the ethyl) derivative. Similarly, HE of SnPr4 in n-C16, br-C16, and n-C8 are much lower than the corresponding heats with SnEt4 and SnBut4. This is attributed to the presence of the exothermic contribution to the heats, HE(steric hindrance). The X12 parameter of the Flory theory has been calculated and is interpreted in terms of the disorder and steric hindrance contributions to the heats.

Characterization of Montmorillonite Saturated with Short-Chain Amine Cations: 2. Interlayer Surface Coverage by the Amine Cations

AbstractPortions of Wyoming bentonite were saturated with a series of short-chain aliphatic amine and quaternary ammonium cations, and the amine content remaining after washing was determined by combustion analysis. For those amine cations containing one or two carbon atoms, the amount of amine found was greatly in excess of the cation-exchange capacity. It is thought that this excess consists of amine cations or uncharged amine molecules which have become partly embedded in the holes associated with the oxygen rings of the silica sheet surfaces. For the larger tertiary amine cations, slightly less than the exchange capacity was found, presumably owing to blocking of some exchange sites by steric interference.Upon treatment of the amine-saturated clays with glycerol and quantitative determination of the glycerol retained as a monolayer, it was found that these clays retain considerably less glycerol than the original bentonite. The glycerol retention values were employed to provide quantitative estimates of the interlayer clay surface left unoccupied between cation pillars. The percentage of original interlayer surface left unoccupied ranged from about 75 percent for methylamine to essentially zero for the larger tertiary amine cations.The validity of the areas calculated from the glycerol retention results was indirectly confirmed by deriving estimates of the cross-sectional areas of the several cations from the observed reductions in amount of glycerol retained. These experimentally derived cross-sectional areas were found to be in satisfactory agreement with areas of the cations projected from atom models.

Characterization of Montmorillonite Saturated with Short-Chain Amine Cations: 1. Interpretation of Basal Spacing Measurements

AbstractBasal spacing measurements were made for a montmorillonite saturated with a series of small aliphatic primary, secondary, and tertiary amine and quaternary ammonium cations, using wet, oven-dry, and glycerol-treated specimens. The spacings ranged from about 12 to 14Å, depending on the cation, indicating that in each case a monolayer of cations is interleaved between adjacent montmorillonite layers. The observed spacings are consistent with the concept that the cations are oriented with their minimum thickness in the c-axis direction, but it is possible that the smallest cations have a long axis in this direction and are partially embedded in the clay surfaces.Montmorillonite saturated with cations containing up to four carbon atoms retained some sensitivity to water, as indicated by a slight contraction of the lattice on oven drying and rapid re-expansion on exposure to the humidity of the laboratory atmosphere.For cations having a layer thickness less than glycerol, limited lattice expansion occurred on glycerol treatment, usually to a spacing sufficient to accommodate a single layer of glycerol molecules. Apparently the cations function as pillars separating the montmorillonite layers, and the glycerol molecules may expand the lattice as necessary to enter the spaces between the pillars. However, exceptions occurred with methylamine-saturated montmorillonite, in which both one- and two-layer complexes of glycerol were present simultaneously in the same specimen, and with trimethylamine-saturated clay, in which two different one-layer complexes were present. It is suggested that the glycerol in one-layer montmorillonite complexes may exist in two orientations, one leading to a layer thickness of about 4.1 Å, the other to a thickness of about 4.6 Å.