Dasteck ChemicalsYantai Dasteck Chemicals Co., Ltd.
Direct answer
Incoming inspection comes down to sampling by batch, checking key figures against the COA and keeping a retention sample. Do not judge quality by packaging condition alone, and never assess purity by appearance.
Four steps
| Step | Detail |
|---|---|
| 1 Document check | Verify COA, batch number and packaging markings against the order; confirm the current SDS revision |
| 2 Appearance and packing | White crystalline powder, no caking, no discolouration; packaging intact with no sign of moisture |
| 3 Sampling and retention | Sample by batch (mix from top, middle and bottom) and retain until after the shelf life |
| 4 Key figure verification | Re-check active content, moisture, thiourea, ash and iron as required |
Key figures and typical limits
| Item | Value |
|---|---|
| Active content | 99% min |
| Moisture | 0.05% max |
| Thiourea | 0.1% max |
| Ash | 0.17% max |
| Iron (II) ion | 0.001% max |
Storage after receipt
Three easily missed points
1. Do not rely on the COA alone: it is supplier data, and incoming verification is the buyer's responsibility, especially when changing supplier or when a batch looks unusual
2. Do not "test" it in hot water: hot water accelerates decomposition and is a destructive step
3. Retention samples are the basis for traceability: without one, a downstream quality problem cannot be traced back
Sources
Limit values are from our product technical data sheet and COA.