When calculating Volatile Suspended Solids (VSS), a filtered sample (previously dried for TSS) is ignited in a muffle furnace. What is the standard temperature and duration for this ignition?

• 180 ± 2 °C for 1 hour
• 103 to 105 °C for 24 hours
• 550 ± 50 °C for 15-20 minutes
• 1000 °C for 5 minutes