Development of a laboratory robotic system for automated bioanalytical methods--II. A robot computer program for guarding totally automated bioanalytical methods.

The application of fully automated, unattended sample preparation performed by a laboratory robot for the analysis of drugs in biological samples requires the prevention of system failures which may arise in the on-line coupled chromatographic system or in other components of the robotic system. A computer program has been developed which can help to detect such problems. The control program for the robotic sample preparation contains a number of safety measures to intercept robotic or human errors. A routine is implemented, guarding for chromatographic malfunctions and errors in dispensing liquids by the robot. After detection of trouble, sample preparation is interrupted.

High performance liquid chromatography of furfural and hydroxymethylfurfural in spirits and honey.

Furfural (2-furaldehyde) and hydroxymethylfurfural (5-hydroxy-2-furaldehyde, HMF) are determined in brandy and honey by reverse phase high performance liquid chromatography. Brandies and other spirits are injected without sample preparation; honey is diluted with water and the solution is filtered before injection onto a reverse phase column with detection at 285 nm. The mobile phase is methanol--water (10 + 90) and the effluent flow rate is maintained at 1.0 mL/min. External standardization is used for quantitative determination. Recoveries from cognac and honey spiked at different levels ranged from 95 to 99% (furfural) and 95 to 100% (HMF). The furfural content of the brandies was also determined by the existing colorimetric method of the Bureau National Interprofessionel du Cognac. The HMF content of the honey was correlated to the results of the classic method of Winkler.

Rapid determination of quinine in soft drinks by reversed phase ion pair chromatography.

Quinine can easily be determined in soft drinks by means of reversed-phase ion-pair chromatography. Sample preparation is not necessary. Quinine is detected by fluorescence and UV spectrophotometry by continuous monitoring of the column effluent. A rectilinear response is obtained in the concentration range of 20--100 mg/l. The complete assay procedure takes about 8 min.

Mass-fragmentographic determination of catecholamine metabolites in amniotic fluid and its possible clinical usefulness.

We describe the determination of 3-methoxy-4-hydroxy-phenylacetic acid, 3-methoxy-4-hydroxyphenylamandelic acid, and 3-methoxy-4-hydroxyphenylethylene glycol in amniotic fluid by means of mass fragmentography, with use of deuterated internal standards. The results expressed in terms of absolute concentration and creatinine concentration, are given as a function of gestational age. In the 15th to 17th week, concentrations in amniotic fluid are a reflection of those in the mother's serum, whereas in the 32nd to 40th week, these concentrations, expressed in terms of creatinine, are similar to those found in the urine of newborns. We discuss the possible usefulness of the determination of catecholamine metabolites in amniotic fluid in the diagnosis of congenital neuroblastoma, maternal pheochromocytoma, and underdevelopment.