Chemical Detection Of Selected Hallucinogens In Water

Abstract

A specific and non-destructive test for basic esters of benzilic and α-glycolic acids in water is described. The compounds are collected on a glass fiber filter as water insoluble complexes with sodium tetraphenylboron. The filter is dried and sprayed with a 2-diphenylacetyl-l, 3-indandione-l-imine derivative. A positive test is the visual observation of fluorescence.     

Determination of Lead in Human Hair by High Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry with Microwave Digestion and Solid Sampling

The content of lead in human hair was measured by high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) combined with microwave-assisted digestion (MAD) and direct solid sampling (DSS). Hair strands were washed, dried, and then cut into three parts (root, middle portion, and tip). For MAD-GFAAS assays, approximately 0.25 g of hair was completely digested using a mixture of concentrated nitric acid and hydrogen peroxide in a closed system. In the DSS-GFAAS assays, 0.1–0.2 mg of dried hair was directly introduced into a graphite furnace using a solid autosampler. The temperature programs were optimized and the effects of various added modifiers were compared. The results indicated that NH₄H₂PO₄ was the optimal modifier for analysis of Pb using GFAAS. Use of the optimal modifier and temperature program gave similar limits of detection for MAD-GFAAS and DSS-GFAAS of 1.16 ng/g and 0.82 ng/g, respectively. Both methods also produced satisfactory recoveries ranging from 98.69% to 103.14%. There was no significant difference observed between the Pb contents of hair strands determined by the MAD-GFAAS and DSS-GFAAS assays, which both indicated that the Pb levels increased along the hair strands. Comparison of the two methods revealed that DSS-GFAAS had several advantageous characteristics over MAD-GFAAS, including the need for much less sample material and having a less time-consuming procedure, lower sample blank absorbance, lower memory effect, and no risk of environmental pollution by digesting chemicals. The direct solid sampling technique can be employed as a good alternative to conventional wet digestion in AAS assays.     

A Rapid Enzymatic Technique for Estimating the Age of Biological Samples

Abstract

An enzymatic method for estimating the age of biological specimens is described. The method is based on the slow racemization of L-aspartic acid to the D isomer. Conditions for protein extraction, enzymatic hydrolysis, pretreatment with stereospecific enzymes and assaying are discussed. The results obtained by this method are compared with the more conventional radiocarbon technique and its application to Holocene climatology is discussed.     

9-Bromomethylacridine a Novel Fluorescent Labeling Reagent of Carboxylic Group for HPLC

Abstract

9-Bromomethylacridine (9-Br · Ma) gave blue fluorescent 9-acridinylmethyl (9-AM) esters by the reaction with carboxylic acids. The reactions were performed simply by mixing the 9-Br · Ma, tetraethylammonium carbonate (TEA C) and carboxylic acids in N,N-dimethylformamide at room temperature. The 9-AM derivatives of fifteen kinds of fatty acids were separated and detected with high performance liquid chromatography. By this method, fatty acids could be determined at levels down to either pmol order by fluorometry or 10 pmol order by UV method. After saponification, those in triacylglycerols were also determined. When four kinds of fatty acids were added to a butter, their recoveries were 92–101%. The coefficient of variation of myristate as a representative was 2.5% (42.8 pmol, n=6).     

Effect of solvent on the construction of Co(II) coordination polymers containing a semi-rigid bis(benzimidazole) derivative: syntheses,structures, and properties

Two Co(II) coordination polymers, [CoL(npa)]·2H₂O (1) and [CoL(Hnpa)₂] (2) (L = 1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene, H₂npa = 5-nitroisophthalic acid), have been synthesized in different solvent systems and characterized by Infrared (IR) spectroscopy, elemental analysis, and powder and single crystal X-ray diffraction. Compound 1 was synthesized under solvothermal conditions with DMF as solvent and had a pair of L ligands adopting a μ₂-bridging mode and connecting two Co²⁺ cations to generate a 26-membered Co₂L₂ loop. The npa^2? link adjacent Co₂L₂ loops via a bis(monodentate) bridging mode to create a 1-D channel-like chain structure. Compound 2 was obtained under hydrothermal conditions, and the carboxylate of the monodeprotonated Hnpa^? adopt a μ₁-η^0?:?η¹ coordination to connect adjacent Co²⁺ cations into a 2-D polymeric layer. The μ₂-bridging L ligands connect adjacent 2-D [Co(Hnpa)]_n polymeric layers into a 3-D NaCl-like framework. The Co²⁺ cations and the L ligands in compounds 1 and 2 exhibit different coordination geometries and conformations. Effects of solvents on the construction of Co(II) coordination polymers were investigated. In addition, the electrochemical behavior of carbon paste electrodes containing 1 and 2 and the thermal stabilities of 1 and 2 were investigated.     

Syntheses and structural characterization of New Tl + and K + complexes of 3,5-dinitrobenzoic acid (HDNB), [Tl(μ-DNB)] n and [K(μ-DNB)(μ-HDNB)] n

Two new Tl⁺ and K⁺ complexes of 3,5-dinitrobenzoic acid (HDNB), [Tl(μ-DNB)] _n and [K(μ-DNB)(μ-HDNB)] _n have been synthesized and characterized by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. Determination of the structure of the [K(μ-DNB)(μ-HDNB)] _n and [Tl(μ-DNB)] _n by X-ray crystallography shows that there are nine coordinate K atoms (KO₉) and eight coordinate Tl atoms (TlO₈). The [Tl(μ-DNB)] _n and [K(μ-DNB)(μ-HDNB)] _n complexes are 2D and 3D coordination polymers, respectively.     

Novel non-aggregated soluble metallophthalocyanines bearing carboxylic acid groups

Synthesis and characterization of zinc and cobalt phthalocyanines substituted with biphenylmethylpropionic acids, methyl-o-tolylpropionic acids, and methyl-p-tolylpropionic acids are described in this study. The new compounds have been characterized by elemental analyses, FT-IR, UV-Vis, MALDI-TOF, and ¹H NMR spectroscopy. All new compounds are soluble in THF, DMF, DMSO, and dilute sodium hydroxide solution. The influence of the carboxylic acid and bulky biphenyl, ortho-methylbenzyl and para-methylbenzyl groups on the spectroscopic properties has been investigated. UV-Vis experiments suggest that the tendency of phthalocyanines to aggregate in polar solvents is significantly reduced owing to the carboxylic acid groups and bulky peripheral substituents.     

Spectroscopic studies and crystal structure of a dimeric Zn(II) complex with diethyl (pyridin-2-ylmethyl)phosphate

The crystal structure of [Zn₂(2-pmOpe)₂Cl₄] (2-pmOpe?=?diethyl (pyridin-2-ylmethyl)phosphate) was determined by X-ray-diffraction method. The compound was also characterized by IR, far-IR, 1H, and ³¹P NMR spectroscopy. In this compound, 2-pmOpe is a bidentate N,O-bridging ligand and Zn(II) are slightly distorted tetrahedral ZnNOCl₂. Zn(II) ions are doubly bridged by the 2-pmOpe ligands, resulting in a dinuclear species. The structure is stabilized by intermolecular C–H?···?O and C–H?···?Cl hydrogen bonds. The spectral properties are in agreement with the structural data.     

A new stable porous Pr-organic framework constructed by multi-iodine-substituted aromatic polycarboxylates: Synthesis,characterization, and selective adsorption of dyes

abstract

Poly[tris(dimethylformamide)(μ3-2,4,6-triiodol-1,3,5-benzene tricarboxylic acid)-praseodymium (III)] {Pr(TIBTC)(DMF)₃}_n (1) (H₃TIBTC = 2,4,6-triiodo-1,3,5-benzene tricarboxylic acid) was synthesized by the reaction of Pr(NO₃)₃·6H₂O and H₃TIBTC at 85°C in a pyrex vial. 1 was characterized by elemental analysis, IR, UV–vis, TGA, PXRD, and atomic force microscopy analytical means. Each of the central Pr ions and the three carboxyl groups from the same ligand constitute a SBU, which is then joined by a carboxyl group to form a building block. In order to further explore the functional properties of 1, we used this compound for adsorption experiments. It is found that 1 can effectively adsorb anionic dyes in aqueous solutions. In particular, there is a good adsorption efficiency for coomassie brilliant blue R-250. Therefore, 1 shows good prospects for selective adsorption of anionic dyes from wastewater solution.     

Synthesis and crystal structure of bis(m-hydroxybenzoato(1-))bis(benzimidazole) copper(II) dihydrate

The crystal structure of the title complex was determined by single-crystal X-ray diffraction methods. The unit cell contains two independent molecules, A and B. B is a mononuclear Cu(II) complex with square-planar coordination geometry formed by two benzimidazole molecules and two hydroxylbenzoate anions. A is a dimer of B, formed by bridging hydroxybenzoate, and copper assumes square-pyramidal geometry. Aromatic π–π stacking is observed between parallel benzimidazole rings of neighboring A molecules. IR spectra of the compound are assigned in line with the crystal structure.