Current Analytical Chemistry - Volume 5, Issue 1, 2009

The heat labile carotenoids cannot be analyzed by gas chromatography (GC) and GC-mass spectrometry (GC- MS). The only useful method appears to be high-performance liquid chromatography (HPLC) with UV/visible (UV/Vis) or mass spectrometric detection (LC-MS). Reversed-phase HPLC (RP-HPLC) is a preferred method, which is frequently used with C18 stationary phase, usually with gradient elution. In contrast to other ioniz Read More

The detection of losses from nuclear material inventories is an important problem to be solved. The present paper considers the detection of such losses by using the fractal dimension of the material balance time series to detect the outliers that are the loss points. We find the proposed method to be successful.

A simple, rapid, selective and sensitive differential pulse anodic stripping voltammetric (DPASV) technique for the direct quantitative determination of inorganic total arsenic in natural hotwater was developed. The electrochemical determination of total arsenic has been carried out at the novel rotating lateral gold electrode in hydrochloric acid solution (37 % w/w). The analysis was performed with a special gold electrode whose Read More

The aim of this study involves the determination of mercury ions at nanomolar level with the employment of the dipyridyl functionalized nanoporous silica gel - chemically modified carbon paste electrode (DPSG-CPE) by anodic stripping voltammetry. The experiments were conducted with a certain electrode composition of 25% paraffin oil, 60% high purity graphite powder and 15% DPSG as well as the usage of 0.20 M Read More

The voltammetric behavior of cinnamic acid (CA) and 3, 4-dihydroxy benzoic acid (BA) at an glassy carbon disc electrode has been investigated. The obtained cyclic voltammograms showed that their oxidation peaks were overlapped and it was difficult to determine them individually from a mixture without separation. To overcome this limitation, partial least squares (PLS) modeling, as a powerful multivariate statistical tool, Read More

A fluorescent chemosensor based on modified β-cyclodextrin was used for the detection of pesticides and herbicides in water. Binding constants, thermodynamic parameters and sensitivity factors were calculated and supported by AM1 semi-empirical method calculation. The results show clearly that a fluorescent chemical sensor based on modified β- cyclodextrin detects quantitatively the presence of pesticides or herbici Read More

A new potassium ion-selective membrane electrode has been developed based on crown ether. The membrane consisted of benzo-15-5 crown ether as a neutral carrier, orto-nitrophenylphenyl ether as plasticizer and PVC as membrane matrix. An analytically useful potential change occurs in the 1x10-6-1x10-2 mol L-1 concentration range. The slope of the linear portion (1x10-2 - 1x10-4 mol L-1) was 56 ± 3 mV/10-fold conc Read More

Glucose assay was conducted on untreated diabetic patient's urine and blood using a combination electrode (CE) whose sensor was interfaced with a newly constructed handheld voltammetry. The CE was prepared using the common graphite pencil as a working electrode, handmade reference electrode, and platinum counter electrode, which were combined into one electrode system. The CE was optimized through cyclic and st Read More

Laminar and pulsed flows typical of multi-commuted and multi-pumping flow systems, were evaluated in relation to analytical procedures carried out at high temperatures. As application, the spectrophotometric determination of total reducing sugars (TRS, hydrolyzed sucrose plus reducing sugars) in sugar-cane juice and molasses was selected. The method involves in-line hydrolysis of sucrose and alkaline degradation of the Read More

A high-resolution NMR spectrum, containing fine structures such as chemical shifts and scalar-coupling multiplet patterns, is helpful for analyzing molecular composition and structure. However, there are many cases where the magnetic environments are inhomogeneous, which may lead to severe signal overlapping and blur useful spectral information in liquid samples. Recently, many NMR techniques have been proposed to Read More