I need to separate the variable “C1” from my payload to write to the bucket. Can you help me with a “parse code”?

22:54:32:
[MQTT] Device publish
{ “topic”: “its/135954/data”, “payload”: “[{“bn”:“135954”,“bt”:1600221269,“bver”:1.3},{“n”:“C1”,“vb”:true}]”, “qos”: 1, “messageId”: 2523 }
{
“topic”: “its/135954/data”,
“payload”: “[{“bn”:“135954”,“bt”:1600221269,“bver”:1.3},{“n”:“C1”,“vb”:true}]”,
“qos”: 1,
“messageId”: 2523
}