State the standard methods typically used to determine sulphur content in lighter versus heavier petroleum products, identifying the appropriate method for each cut.

Introduction:
Sulphur determination methods in petroleum vary with boiling range and matrix. Lighter fractions are amenable to older lamp (Wickbold-type) or similar combustion methods, whereas heavier, more viscous materials require closed-vessel (bomb) combustion to ensure complete oxidation for accurate sulphur analysis.

Given Data / Assumptions:

• Two product classes: lighter vs heavier petroleum products.
• Methods considered: lamp method and bomb method (closed combustion).

Concept / Approach:
Select the method that ensures complete combustion and reliable capture of sulphur for the given volatility/viscosity range: lamp method for light ends; bomb method for heavy stocks and residues.

Step-by-Step Solution:

Verification / Alternative check:
Analytical standards historically align lamp/open combustion with light distillates and closed-bomb with heavy residues for completeness and safety.

Why Other Options Are Wrong:

Common Pitfalls:
Assuming one universal method suits all fractions; matrix drives method choice.

Final Answer:
Lamp method for light products; bomb method for heavy products