Hexavalent chromium measurement context
EPA Method 7196, colorimetric: in acid solution, hexavalent chromium reacts with diphenylcarbazide to form a red-violet color measured by spectrophotometry. Only the hexavalent form reacts, so the result differs from total chromium in a metals test. Water results are reported as mg/L. Solid samples can also be tested; the preparation and reporting basis are confirmed when you order. Organic indicators
Define where the property is measured
Specify field or laboratory measurement, units and the sample state needed for the project. A delivered sample may not preserve the source-time condition for a changing property.
Include the complete project requirement
Provide the matrix, target analytes, required method, fraction, units and reporting limits. Include the permit or monitoring instructions where results will support a regulatory submission. Naming this method does not establish blanket compliance eligibility.
Resolve collection before sampling
Use the bottle, preservation and delivery instructions assigned to the agreed scope. Identify each location and collection time, and document any deviation. The final analytical plan must fit the submitted material and its intended use.
Related testing & guidance
Technical & service references
Vanguard service detailsSource review: November 8, 2026. The agreed method and project scope govern the testing.