AOAC ERP Fertilizers - March 2019
3/14/2019
AOAC EXPERT REVIEW PANEL FOR FERTILIZERS
UPDATE ON ADDITIONAL VALIDATIONS AND NEXT STEPS FOR THE METHOD • Method “updates” – Nebulizer change • OptiMist XL® Nebulizer • Why: • Virtually unclog‐able • Reduces need for sample filtering • Sample channel is > 1.0 mm • Introduction or pump tubing will clog first
Sample Orifice
Sample Channel
Gas Orifice
• Relatively Inexpensive • Extended life (1‐2 yrs) • Non‐concentric nebulizer
Gas Channel
• May be a slight loss in RSD precision & MDL versus a concentric, but not likely a problem for high P/K fertilizers • With P, want to minimize introduction of aerosol into the plasma (i.e. high Carbon and ionization requirement) so set pump rpm just above aerosol pulsation
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AOAC EXPERT REVIEW PANEL FOR FERTILIZERS
UPDATE ON ADDITIONAL VALIDATIONS AND NEXT STEPS FOR THE METHOD • If still need low MDLs and RSDs, there is another non‐concentric option, but it has a higher clogging potential. • OptiMist Vortex® • Has “striker plate” • Requires a different spray chamber
• TSP contact info:
Texas Scientific Products, LLC 11941 Hilltop Road, Suite 15 Argyle, TX 76226 Main Number: 888‐268‐6037 www.txscientific.com
Data is courtesy of University of KY, Division of Regulatory Services Fertilizer Program
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