The elemental analyzer sample carousel: loading an autosampler made easy Matthew Wooller*, Bert Collins and Marilyn Fogel Carnegie Institution of Washington, 5152 Broad Branch Road, NW, Washington, DC 20015-1305, USA Received 21 August 2001; Accepted 2 September 2001 SPONSOR REFEREE: Dr Brian Fry, Institute of Pacific Islands Forestry, USDA Forest Service, 1151 Punchbowl St., Room 323, Honolulu, Hawaii 96813, USA A newly developed device for loading samples into an autosampler attached to an elemental analyzer is described and evaluated. The purpose of the device is to reduce the time and number of errors experienced when loading samples into an autosampler. Tests show that the new device saves time when loading samples and, more importantly, reduces the chance of losing samples. In addition to analyzing the elemental components e.g. % carbon and % nitrogen) and the elemental ratios e.g. C/N) of a sample, the stable isotopic composition e.g. d 13 C and d 15 N) can also be determined when an EA is attached to a stable isotope ratio mass spectrometer. Copyright # 2001 John Wiley & Sons, Ltd. Elemental analyzers EA) feature as prominent components of many analytical laboratories and produce data that contribute to addressing diverse scientific questions. In addition to analyzing the elemental components e.g. % carbon and % nitrogen) and the elemental ratios e.g. C/N) of a sample, the stable isotopic composition e.g. d 13 C and d 15 N) can also be determined when an EA is attached to a stable isotope ratio mass spectrometer IRMS). Elemental analyzers are most often fitted with autosamplers to maximize productivity. These autosamplers consist of a carousel with up to 50 wells, each of which accommodates a single sample. In some systems carousels can be stacked to allow multiple runs of samples to be loaded. Once the analysis of a run has been initiated, the carousel rotates, loading each sample in turn. Preparing samples for elemental analysis is tedious, labor intensive and time consuming. The final stage of preparation involves weighing each sample into a tin or silver capsule, which is then crimped into a small ball. At this stage of preparation all samples are apparently identical. Many laboratories with elemental analyzers traditionally use cell culture cluster CCC) trays or individual microcentrifuge tubes for storing samples that have been weighed into tin capsules. Although functional, CCC trays are not ideal for transferring samples from a weighing station to an auto- sampler. For instance, a CCC tray consists of a series of wells in rows. Columns are numbered 1±12 while the rows are labeled A±F; a system that is not intuitive, since the positions of samples in an autosampler are numbered, typically 1 through 50. Moreover, a traditional method using a CCC tray or microcentrifuge tube) requires two stages of handling samples with forceps before they are loaded into the autosampler Fig. 1a)). The first stage involves placing each weighed sample into a container. The second stage then involves removing the samples from the container, using forceps, and placing each into a position in the autosampler. Figure 1. Schematic of the procedure for loading samples into an autosampler using (a) a CCC tray (Top) and (b) the EA sample carousel (Bottom) (NB the illustration only shows 15 rather than the actual 50 holes in the autosampler). *Correspondence to : M. Wooller, Carnegie Institution of Washing- ton, 5152 Broad Branch Road, NW, Washington, DC 20015-1305, USA. DOI:10.1002/rcm.468 Copyright # 2001 John Wiley & Sons, Ltd. RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2001; 15: 1957±1959