Non-proximate Sampling and Photoionization for Damage-Free Mass Spectrometric Analysis of Intact Native American Baskets.

Selected examples of Native American woven woodsplint basketry created between 1870 and 1983 are studied to recover traditional knowledge about their manufacture by identifying dyes or colorants. An ambient mass spectrometry system is designed to sample from intact objects with minimal invasiveness, neither cutting solids from the whole, exposing objects to liquid, nor leaving a mark on a surface. Baskets up to 60 cm wide in one dimension are placed on height-adjusted mounts. A timed jet of inert nitrogen from a finely positioned probe thermally desorbs neutral material from a mounted item, and a heated transport tube carries the analyte 2 m away at 4.9 L/min. Gas phase analyte is mixed with anisole dopant from an in-line permeation tube and photoionized in a reaction tee immediately before entering the mass spectrometer, identifying dye molecules in real time. Extensive optimization and exposure tests with flat and near-flat splints of dyed wood ensure that the analysis produces no discoloration on the curved and contoured basket splints.