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Fluorescence enhancement of the [Eu.sup.3-]-tetracycline complex by DNA or RNA was studied. Studies involving natural and denatured fish sperm DNA, calf thymus DNA, and yeast RNA revealed that double-stranded and single-stranded DNA is capable of enhancing the fluorescence of the [Eu.sup.3-]-tetracycline complex, while RNA showed very little enhancement effect, which rounded a basis for selective determination of DNA in the presence of RNA. Maximum fluorescence was produced in the pH range 8.0-9.7, with maximum excitation and emission wavelengths at 398 and 615 nm, respectively. Under optimal conditions, the calibration graphs were linear between 0.02 and 1.0 [[micro]gram] [mL.sup.-1] for both double-stranded calf thymus and fish sperm DNA. The corresponding detection limits were 0.01 [[micro]gram] [mL.sup.-1]. The relative standard deviation (seven replicates) was within 3.0% in the linear range. DNA could be determined in the presence of yeast RNA. If the time-resolved mode was used, the low end of the linear range could be extended to 0.005 [[micro]gram] [mL.sup.-1], with a detection limit of 0.003 [[micro]gram] [mL.sup.-1]. The mechanism for the fluorescence enhancement was also studied.

In the report molecularly imprinted polymer (MIP) with salicylaldehyde-Cu(OAc)2 as the template was synthesized and characterized by SEM, porosity and elemental analysis. Copper acetate was introduced since salicylaldehyde alone cannot display imprinting effect for its intramolecular hydrogen bond. The strong coordination interaction between salicylaldehyde and copper acetate made the complex have high retention on the HPLC column based on the SAD-Cu(OAc)2 imprinted polymer. Several structural analogues such as salicylaldoxime, sulfosalicylic acid, p-hydroxybenzaldehyde and their complexes with copper acetate were chosen to study the selectivity of the MIPs. The influence of acetic acid and H2O in methanol mobile phase was studied. The experimental results showed that small amount of either acetic acid or H2O in mobile phase would weaken the interaction between the complex and the polymer, therefore, the retention of the complex was lowered to a large extent, but that of salicylaldehyde remained almost unchanged. The polymer imprinted with the complex showed high selectivity to both the acetate and copper (II). In addition, the MIP showed an enhanced selectivity to its template compared with the polymer prepared without copper acetate. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this study, molecularly imprinted polymers (MIP) with p-acetaminophenol (p-AMP) and its positional isomers as templates were synthesized. Several structural analogues, phenol, acetanilide (AN), p-nitrophenol (p-NP) and p-aminophenol (p-AP) were chosen to study the selectivity of the MIPs in different mobile phases. In addition, the separation of the positional isomers was also investigated. The experimental results showed that, in the mobile phase with less polarity, the retention of the compounds was increased greatly on both blank polymer and the MIPs, thus leading no enhancement in the imprinting effect and selectivity. In addition, the use of dichloromethane/acetonitrile as the mobile phase favors the separation of the positional isomers, and baseline separation can be achieved only on the column based on the polymer imprinted with m-acetaminophenol (m-AMP) as a template. [ABSTRACT FROM AUTHOR]