Environmental Reference Materials, Inorganics, Water Chemistry CRMs Silica #IS-021 $33.00 – $51.00 1000mg/L in Water read more Options Choose an option125 mL500 mLClear Add to cart Compare Catalog Number: IS-021. Options 125 mL, 500 mL Related products Quick View Add to cart Compare $59.00 Environmental Reference Materials Iodide – 125mL #IC-051 Quick View Add to cart Compare $59.00 Environmental Reference Materials Chloride – 125mL #IC-013 Quick View Add to cart Compare $59.00 Environmental Reference Materials Phosphate – 125mL #IC-040 Quick View Add to cart Compare $59.00 Environmental Reference Materials Chlorate – 125mL #IC-010