Table 2.

Labelling in the γ‐glutamyl cycle.

Metabolite	Peak heights, control ×106	Peak heights, BaP ×106
Glutamate C4[a]	doublet: 6.22+4.67	doublet: 8.00+5.94
	singlet: 8.24	singlet: 12.9
	ratio: 1.3	ratio: 1.1
Glutathione C4[a]	doublet: 1.23+1.16	doublet: 1.01+0.92
	singlet: 2.2	singlet: 2.26
	ratio: 1.1	ratio: 0.9
Pyroglutamate C3[b]	4.55, 3.85	14.7, 15.9

[a] ¹³C4 signal intensities for doublet (arising from coupling to ¹³C3) and singlet (with ¹²C3). [b] Directly observed C3 signal intensities for H_a and H_b.