DETERMINATION OF BORON IN CELL-SUSPENSIONS USING ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY

A simple and sensitive method for the determination of boron in cell s uspensions has been developed. Following incubation of cultured B16F1- mouse melanoma cells with various concentrations of boronophenylalanin e (BPA), the cells were washed and removed mechanically from their sol id matrix or were trypsinized. All the samples were analysed by electr othermal atomic absorption spectrometry employing a modified autosampl ing system. A limit of detection of 0.05 mg of boron per litre of susp ension could be achieved, which is within the range of that of direct current plasma atomic emission spectrometry (0.10 mg l-1) and inductiv ely coupled plasma atomic emission spectrometry (0.05 mg l-1). The pre cision of the boron determination in cell suspensions is 100 +/- 5.7%. The method which is introduced here is an improvement over existing t echniques because it eliminates a time-consuming sample digestion, nor mally involving loss of boron. Modern digestion procedures involving m icrowave-induced heating can compensate for the loss of boron. Further more, the boron concentration determined in cell suspensions varies wi th the method of cell detachment. In any case, high boron accumulation in cells, using BPA, of up to 159 micrograms of boron per gram of mel anoma cells was registered.