Determination of nanogram levels of boron in milligram-sized tissue samples by inductively coupled plasma-atomic emission spectroscopy

✍ Scribed by D.A. Johnson; D.D. Siemer; W.F Bauer

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 591 KB
• Volume: 270
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(92)80111-j

✦ Synopsis

This paper describes a simple modification to the sample introduction system of a standard inductively coupled plasma-atomic emission spectroscopy (ICP-AES) spectrometer that allows the determination of nanogram quantities of boron. This modification was applied to the part-per-million quantitation of boron in tissue samples in the range of 1-30 mg. Boron is converted to the volatile methoxyborate ester, which is immediately swept/aspirated into the torch with argon carrier gas. These small tissue samples are prepared by first moistening them with a drop or two of sodium hydroxide solution and then dry ashing them in small platinum crucibles. After cooling, 100 ~1 of concentrated sulfuric acid are weighed into these crucibles to dissolve the ash. The first step of the actual determination involves weighing aliquots of this acid into the plastic test tubes that subsequently serve as the esterification reaction vessel. A simple adaptor inserted into these tubes permits the suction generated by a standard concentric flow ICP-AES nebulizer to pull an argon carrier gas stream through the headspace volume of the tube. When methanol is added, the gaseous boron ester forms and is immediately swept into the torch. The absolute detection limit is on the order of 0.2 ng.