Table 1.

All reagents used for sample preparation with nPOP

	Reagent	Dispense conc.	Volume added	Concentration in droplet
1	DMSO	100 %	8 nl	100 %
2	Cell	300 cell/μl in 1× PBS	300 pl	1 cell
3	Digest mix		13 nl	60 % (aq)
	Trypsin Gold (aq)	150 ng/μl		90 ng/μl
	HEPES (aq)	6 mM		4 mM
4	TMT (DMSO)	8.3 μg/μl	30 nl	8.3 μg/μl
5	mTRAQ (DMSO)	8.3 μg/μl	30 nl	8.3 μg/μl
6	TEAB (aq)a	200 mM	20 nl	50 mM
7	Hydroxylamine (HA)	5 %	2 × 20 nl	3 %

Listed are volumes added, concentrations in the dispensing solution, and concentrations in the droplets

^aAqueous TEAB solution is added only for mTRAQ labeling (not for TMT) since it is required for optimal mTRAQ labeling