how to check purity of copper

{"title":"P120BCPC P125BCPC P130BCPC Soldering Iron Tip Black Chromium Plated","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/4f\/0f\/f80b6e365c1ebebd0ec788541984-200x200-1.jpg","attrs":{"Price":"USD","Model Number":"P120BCPC, P125BCPC, P130BCPC","Minimum Order Quantity":"1 piece","Delivery Time":"1 to 2 working days","Place of Origin":"China","Payment Terms":"L\/C, D\/A, D\/P, T\/T, Western Union, MoneyGram, Paypal","Supply Ability":"10 pcs.","Packaging Details":"Carton box","Application":"Robot Soldering Machine Accessories","Description":"Robot Soldering Iron Tip (CROSS BIT for 200W CROSS-HEATER)","Part Number":"P120BCPC, P125BCPC, P130BCPC","Material":"High-purity copper, Black chromium-plated tips","Condition":"New","Lead Time":"1 to 2 working days","Packaging":"Carton box","Payment":"L\/C, D\/A, D\/P, T\/T, Western Union, MoneyGram, Paypal"}}

{"title":"0.85m Cat5 Ethernet Cable Rj45 Male To Female Ethernet Extension Cable","imgUrl":"https:\/\/img.silkroadsl.com\/nimg\/50\/4c\/4932fad53afc65b4d76f5c9abcc1-200x200-1.jpg","attrs":{"Price":"USD2.26\/pc-USD3.33\/pc","Brand Name":"OEM\/ODM","Model Number":"VY-Ethernet Network-10","Minimum Order Quantity":"500Pcs","Delivery Time":"1-2weeks","Certification":"\/","Place of Origin":"China","Payment Terms":"T\/T","Supply Ability":"To be negotiated","Packaging Details":"Bag","Product name":"Male to female rj45 with ear cat5 super five \tEthernet network cable","Color":"Black\/White","Jacket":"PVC","Length":"0.85m\/1m\/2m","Keyword":"Network Cable","Application":"Computer"}}