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Laser ablation-inductively coupled plasmamass spectrometry (LA-ICP-MS) was used as a complementary technique to X-ray¯uorescence (XRF), for multi-element analysis of geological samples fused with lithium-tetraborate Li 2 B 4 O 7 . Different calibration strategies using external non-matrix matched reference materials were investigated. Various internal standards were tested, including the use of Li from the¯ux, and the use of the naturally occurring internal standards, Si or Ca. The use of a naturally occurring standard is not as ef®cient as this required a prior analysis of the samples using XRF. The obtained values for the analysis of geological reference materials were compared with consensus literature values, and satisfactory agreement was found. Laser pits, which were formed, had a diameter of 80 mm and 3±5 replicates on each fused disc were measured. The reproducibility of the method was better than 10% for concentrations above 1 mg/g and better than 15% for lower concentrations. The use of Li as the internal standard offers the possibility of multielement determinations in geological samples, which have an unknown composition when the laser ablation analysis is carried out. However, using the calculated stoichiometric composition of the lithium-tetraborate for the calculation of the Li concentration leads to a constant deviation from the recommended values. Therefore, it was necessary to determine the Li concentration within each sample batch using at least one lithium tetraborate fused geological reference material. This resulting Li concentration in the beads was then used for all subsequent samples in a run. Limits of detection, reproducibility, deviation from reference values indicate the potential of LA-ICP-MS for such bulk analysis without matrix matched calibration standards.

2I−VI,3I−VII,6I−VII‐Eicosa‐O‐methyl‐2I‐O‐(oct‐7‐enyl)cyclomaltoheptaose, 2I−VII,3I−VI,6I−VII‐eicosa‐O‐methyl‐3I‐O‐(oct‐7‐enyl)cyclomaltoheptaose, and 2I−VII,3I−VII,6I−VI‐eicosa‐O‐methyl‐6I‐O‐(oct‐7‐enyl)cyclomaltoheptaose were synthesized by selective introduction of an oct‐7‐enyl group at one of the O‐2, O‐3, or O‐6 positions of selectively methylated cyclomaltoheptaose (β‐cyclodextrin, CD) and, depending on the synthetic route, by a subsequent permethylation step. Each of the regioisomeric mono‐oct‐7‐enylated permethylated β‐cyclodextrin derivatives was anchored by hydrosilylation to a hydridomethyldimethylsiloxane copolymer to yield unambiguously O‐2‐, O‐3‐, and O‐6‐bonded chiral stationary phases (CSP) of Chirasil‐Dex, which were evaluated in enantioselective gas chromatography (GC). O‐6‐Chirasil‐Dex displayed slightly inferior enantioselectivity relative to either O‐3‐ or O‐2‐Chirasil‐Dex. The statistical synthesis of the CSP by mono‐oct‐7‐enylation of β‐CD under varying reactions conditions (base, solvent), without the use of hydroxy group protection chemistry, furnished a mixture of O‐6‐ and O‐2‐Chirasil‐Dex in dimethylformamide and predominantly the O‐2‐regioisomer in dimethyl sulfoxide. Chirasil‐Dex, previously formulated exclusively as the O‐6 regioisomer, should be revised as an O‐2‐ and O‐6‐Chirasil‐Dex mixture. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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