Table 5.

Standard operational procedure for dDNP experiments.

No	Operation	Duration	Comments	Norm values
1	Check T of VTI (P1, P2)			T = 1.38–1.4 K P1 ≈ 1.3 mBar P2 ≈ 250–350 mBar
2	Warm up stock CA-radical concentrate until liquid	10 min	Protect from light
3	Flush fluid path with air	10 min	Automatic
4	Add CA-radical concentrate to cup	5 min	Use micropipet, add to the bottom, avoid smudging to walls	18–19 µL ≈ 22 mg (for 13C) And 50 uL ≈ 50 mg (for 15N)
5	Prepare liquid nitrogen (lN2)	2 min	Place non-magnetic dewar next to the magnet	< 500 mL of lN2
6	Connect sample cup to polarizer: - Connect empty cup - Flush with He - Disconnect cup, connect cup with a sample - Dip cup in lN2 - Pressurize fluid path	3 min	Mark vial to avoid damage to thread by over tightening Use cryogenic gloves Immerse slowly into lN2 Pressurize while in lN2	Immersion into lN2 for 30 s
		20 s
7	Insert cup into VTI	5 min	Hurry but stay calm: open airlock, remove plug, insert sample, close airlock, start automatic insertion procedure Manually guide tube if needed. Use gloves
8	Position cup in VTI/NMR coil		Mark lowest position on tube e.g. with tape	10 mm above lowest position
9	Check that the NMR coil is in resonance	2 min	Adjust tuning and matching capacitors	Tune within ± 20 kHz, match 1–2%
10	Wait for temperature T and pressure to stabilize (P1, P2)	5 min	Insertion causes temperature and pressure increase	Close to starting temperature, e.g. T = 1.38 – 1–4 K
11	Start DNP 11a: start monitoring 13C NMR (SpinIt) 11b: start DNP (SpinAligner)	60 min	Check that µW is on Check 13C NMR signal
12	Prepare MRI/NMR		Adjust resonance of the probe, create a new protocol, shims of the system, create new project, free space to ease transport
13	Inject dissolution medium in heater		Standard dissolution medium suitable for tracer	5 mL
14	Initiate heating of dissolution medium	5 min	Close the cover of polarizer	Automatic, ready when 11 bar reached
15	Prepare receiver vessel/syringe		Weigh and label NMR tubes and place receiver in the stray field
16	Put on safety equipment: Goggles, gloves		Caution! Hot liquids, high pressures!
17	Raise cup	30 s	Raise cup above lHe level to reduce lHe boil off	Rise by 8 cm
18	Execute dissolution	< 30 s	Hot liquid at high pressure and speed will be ejected	Automatic
19	Collect hyperpolarized medium e.g. to syringe and apply	5 s	Draw in syringe for manual injection, transfer via tubes to detection site
20	Transfer NMR samples or syringe to NMR/MRI and execute pulse sequences when sample is at the detection position	30 s	A fast transfer is necessary
21	Take out the sample cup, conserve the airlock, perform the cleaning	15 min	Wash the heater 3 times with deionized water, then dry at least 10 min	10 mL of water to clean the system each time