Ammonium Standard: NH4+, 1000µg/ml in Water, 100ml Back Catalog number: VHG-INH41K-100 Availability: In the manufacturer's stock Price on request - + Recommended 92357 EPA Method 8141/1657 Surrogate Standard Price on request 71405 N-Methylaniline Price on request S-4341-10K-HXX5 Quality Control Standard of Mineral Oils 2 2x5000µg/ml in n-Hexane i 1ml crimp-top Price on request