Quantifying Historic Pesticide Residues on Collections: Practical Approaches with micro-XRF

Throughout the 19th and 20th centuries, pesticides containing heavy metals such as arsenic, lead, mercury, and bromine were widely applied to protect museum collections. Today, these residues remain on objects, creating both health and conservation challenges—particularly for museum workers or items now subject to repatriation initiatives.

Micro- and also handheld X-ray fluorescence (XRF) spectroscopy is commonly used to study such substances, and qualitative identification often suffice. However, situations such as risk assessment, treatment planning, or collection surveys require quantitative data. Reliable concentration analysis is difficult because quantitative XRF analysis assumes homogenous samples, while pesticide residues usually form thin, uneven surface layers. Rather than a limitation, this can be addressed through adapted data interpretation.

This webinar will present practical approaches to quantifying residues in terms of mass deposition, supported by case studies on organic materials. The method combines standard addition with safe, self-made mock-ups mimicking pesticide deposits, enabling validation across diverse objects. By outlining best practices, limitations, and transferable workflows, this contribution provides conservators and heritage scientists new tools to extend XRF analysis beyond detection toward meaningful quantification.

Bruker: Cloth with varying amounts of non-poisonous KBr solution used for creating calibration curves for quantitative analysis: (a) VIS; (b) Br-Kα distribution, M6 JETSTREAM, 50 kV, 600 µA, 40 µm spot, 300 µm pixel, 50 ms/px, 2x 60 mm2 SDD.

Bruker: Oak wood mock-ups with varying amounts of non-poisonous KBr solution to study penetration properties of pesticides in wood: (a) VIS; (b) Br-Kα, variation of amount at same concentration; (c) Br-Kα, varying concentration at same amount; (d) Cross-section through application. M4 TORNADO, 50 kV, 600 µA, 20 µm spot, 60 µm pixel, 10 ms/px, 2x 60 mm2 SDD.

Who should watch?

• Heritage and Conservation Scientists
• Collection care
• M4 TORNADO, M6 JETSTREAM, CRONO, and ELIO and IRIS users

Presenter: Dr. Mareike Gerken (Application Scientist, Bruker AXS)

Presenter: Dr. Roald Tagle (Global Manager Application Science, Bruker AXS)