Optical potentials for the scattering of K± from 6Li and 12C nuclei are calculated using the Watanabe superposition model in terms of the alpha-particle and deuteron optical potentials. The elastic and inelastic scattering differential cross-sections obtained using these potentials are compared with experimental data. Good fits are obtained without modifying any of the parameters. Further measurements for K± scattering from 6Li are stressed.

The present study introduces two novel organic matrices for matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS) for the analysis of small molecules. The first matrix is “2-amino-4,5-diphenylfuran-3-carboxylic acid” (also called furoic acid, FA) which was synthesized and then characterized by ultraviolet (UV), infrared (FTIR), nuclear magnetic resonance NMR (1H and 13C) and mass spectrometry. The compound has organic semiconductor properties and exhibits intense UV-absorption which is suitable for the UV-MALDI laser (N2 laser, 337 nm). The second matrix is mefenamic acid (MA). The two matrices can be successfully applied for various classes of compounds including adenosine-5′-triphosphate (ATP, 0.5 µL(10.0 nmol)), spectinomycin (spect, 0.5 µL(14.0 nmol)), glutathione (GSH, 0.5 µL(9.0 nmol)), sulfamethazole (SMT, 0.5 µL(2.0 nmol)) and mixture of peptides gramicidin D (GD, 0.5 µL (9.0 nmol)). The two matrices can effectively absorb the laser energy, resulting in excellent desorption/ionization of small molecules. The new matrices offer a significant enhancement of ionization, less fragmentation, few interferences, nice reproducibility, and excellent stability under vacuum. Theoretical calculations of the physical parameters demonstrated increase in polarizability, molar volume and refractivity than the conventional organic matrices which can effectively enhance the proton transfer reactions between the matrices with the analyte molecules. While the reduction in density, surface tension and index of refraction can enhance homogeneity between the two new matrices with the analytes. Due to the sublimation energy of mefenamic acid is (1.2 times) higher than that of the DHB, it is more stable to be used in the vacuum.

A selective, rapid, small sample load (2–4 μL), and sensitive quantification method for the hydrophobic cellular biomolecules of pathogenic bacteria and their biosensing application were reported. The present approach is based on using polythiophene polymer dots (2.5 nm), which were prepared via the oxidation/polymerization reactions and then were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), ultraviolet spectroscopy (UV), and matrix (surface) assisted laser desorption/ionization mass spectrometry (M(S)ALDI-MS). The present method requires only gentle agitation for a single drop of aqueous bacteria suspension (10 μL, Pseudomonas aeruginosa (1 × 104 cfu/mL) and Staphylococcus aureus (1 × 105 cfu/mL)) with 1 mL of polythiophene (0.5 mg/mL) in chloroform, and the time required for quantifying the total hydrophobic was significantly reduced to less than 3 min. The polythiophene polymer dots is also a quantitative assessment of bacteria for aqueous and blood samples if exposed to more than 4–5 μL of pathogenic bacteria and thus, it is a new biosensor for quantitative hydrophobic portions. The fluorescence intensity of polythiophene was enhanced after adding different volumes of pathogenic bacteria with low colony units. The standard bacteria suspensions of P. aeruginosa and S. aureus have low LOD (limits of detection) for 2 μL (1 × 104 cfu/mL) and 4 μL (1 × 105 cfu/mL), respectively. Further, the pathogenic bacteria were spiked into mouse blood and the total hydrophobic biomolecules were quantified. This method is extremely rapid as it does not require any culture steps prior to analysis and also no need for any separation or post sample treatments.

Tobramycin is an aminoglycoside antibiotic that shows antimicrobial activity against a wide spectrum of aerobic bacteria. This paper describes the electrospray ionization mass spectrometric analysis of metallo (Cu(II) and Fe(III))–tobramycin complexes. The Cu(II) (1.5 × 10−4 M) and Fe(III) (1.5 × 10−4 M) ions co-ordinate with tobramycin (1.5 × 10−4 M) at 1:1 molar ratio for 30 min at room temperature. ESI mass spectrum of tobramycin shows ions at m/z 468.1, 934.8, and 234.8 corresponding to mono-protonated ([M+H]+), dimer ([2M+H]+) and di-protonated ([M+2H]2+), respectively. The Cu(II) and Fe(III) complexes show preferentially different molar ratio as 1:1, 1:2 and 1:3 such as [63Cu+(M−2H)+H]+, [65Cu + (M−2H) + H]+, [63Cu + (M−2H) + 2H2O + H]+, [65Cu + (M−2H) + 2H2O + H]+, [Fe + (M−3H) + 2H2O + H]+, [Fe + (2M−3H) + 2H2O + H]+, [Fe + (M−3H) + H2O + H]+ and [Fe + (M−3H) + H]+, respectively. Therefore, ESI-MS provides a simple, accurate and reproducible method for the identification of Cu(II)– and Fe(III)–tobramycin complexes ions than the other conventional methods (the method of continuous variations, the mole-ratio method, the slope-ratio method, computer-based curve-flitting methods).