Abstract: Disclosed is an electrochemical cell and a method for separating carrier-free radionuclides from a solution on an electrode. 18F? is precipitated in an electrochemical cell from an aqueous solution on an anode, which is diamond-coated. Subsequently, the electrochemical cell is dried and supplied with a liquid containing a transfer catalyst, the anode is preferably switched to serve as the cathode, and 18F? is transferred to the liquid phase.

Abstract: The invention relates to a flow cell, a method for separating carrier-free radionuclides from a liquid or liquefiable target material, and the radiochemical reaction thereof. According to prior art, flow cells are known which require reaction volumes corresponding to the volume of the target material in order to carry out the desired reactions. The inventive flow cell (1) and method enable the reaction volume, and thus the quantity of starting material, to be reduced by a multiple by reducing the cylinder volume (=reaction volume). As the radioactively marked product is present in very small quantities (picomole to nanomole), the HPL-chromatographic separation of the non-reacted starting material is significantly improved. The economic efficiency of the method is increased due to the fact that small quantities of starting material can be used.

Abstract: The invention relates to a flow cell, a method for separating carrier-free radionuclides from a liquid or liquefiable target material, and the radiochemical reaction thereof. According to prior art, flow cells are known which require reaction volumes corresponding to the volume of the target material in order to carry out the desired reactions. The inventive flow cell (I) and method enable the reaction volume and thus the quantity of starting material, to be reduced by a multiple by reducing the cylinder volume (=reaction volume). As the radioactively marked product is present in very small quantities (picomole to nanomole), the HPL-chromatographic separation of the non-reacted starting material is significantly improved. The economic efficiency of the method is increased due to the fact that small quantities of starting material can be used.

Abstract: The compound O-(2-[18F]fluoroethyl)-L-tyrosine has proven to be particularly suitable for positron emission tomography and has already been tested in clinical practice. Until now, the compound has been prepared according to a relatively laborious method (Wester H. J. et al., J. Nucl. Med. 1999; 40: 205-212). The invention relates to L-tyrosine derivatives of the formula (1) whereby R1 represents a suitable protective group for the carboxy group, R2 a suitable protective group for the amino group and R3 a suitable leaving group, R1 represents a methylthiomethyl group, a tetrahydrofuranyl group, a diphenylmethyl group, a para-methoxybenzyl group, a piperonyl group or a tert-butyl group, R2 an alkyl- or an arylalkyl group and R3 a p-tosyloxy, methanesulfonyloxy, trifluoromethanesulfonyloxy or bromine. The invention also relates to a method for preparing O-(2-[18F]-fluoroethyl)-L-tyrosine from the initial compounds of formula (1) and method for the preparation of these initial compounds.

Abstract: The compound O-(2-[18F]fluoroethyl)-L-tyrosine has proven to be particularly suitable for positron emission tomography and has already been tested in clinical practice. Until now, the compound has been prepared according to a relatively laborious method (Wester H. J. et al., J. Nucl. Med. 1999; 40: 205-212).

Abstract: Furanosides or pyranosides can be reacted with pyruvate and converted into sialic acids in good yields by an enzymatic synthesis, using a suitable aldolase, where the concentration of aldolase, per 50 mM of pyruvate, is 1 to 2,500 U*/ml. For example, 3-fluoroneuraminic acid and other 3,3-didesoxy-3-fluorononulopyranosonic acid derivatives can be prepared in this manner. The F-atom in the resulting sialic acid (which can be 19F or 19F and 18F) provides a label which makes possible studies of mammalian physiology and diagnosis of mammalian diseases.

Abstract: Ionizable or polarizable, carrier-free radionuclides may be separated by electrofixation, from a low electric conductivity liquid target material in a flow cell fitted with a permanent electrode arrangement. The target liquid is separated while the fixing voltage is maintained; then the fixed radionuclide is removed again from the electrode, if required by heating, after switching off or reversing the poles of the field, after an optional intermediate rinsing.

Abstract: Organic compounds labeled with no-carrier-added fluorine 18 are processed yield a compound having a formula in the form of .sup.18 F-R through a nucleophilic substitution reaction. The process has a series of steps. The first step of the process relates to providing an organic compound having a formula of X-R. X is the nucleophilic leaving group in the substitution action, and R is a preferred substituted hydrocarbon structure being selected from aliphatic, alicyclic, heterocyclic aliphatic, carbocyclic and heterocyclic aromatic structures. The X-R compounds with acid hydrogen are excluded. The next step is to bring the organic compound X-R into contact with fluoride ions which are present in a solvent. These fluoride ions are essentially carrier free .sup.18 F ions. The organic compound is brought into contact with the fluoride ions in an apparatus to produce a reaction.