Microcoil flow probes

R354 O. Goekay and K. Albert, From Single to Multiple Microcoil Flow Probe NMR and Related Capillary Techniques A Review , Anal. Bioanal. Chem., [online computer file], 2012, 402, 647. 

Figure 12 Comparison of detection volumes of various NMR probes. Volume is indicated within brackets (A) CE-NMR microcoil (0.030 pL) (B) MRM flow probe (1.5 pL) (C) 1-mm Bruker probe (2.5 pL) (D) 1.7-mm Nalorac probe (20 pL) (E) Nalorac flow probe (24 pL) (F) 2.5-mm Bruker flow probe (30 pL) (G) Varian nanoprobe (40 pL) (H) 3-mm Varian probe (60 pL) (I) 5-mm probe (220 pL).

LC/NMR) flow probes [50-52], such as microcoil/CapNMR probes [48,49,... 

There are also more specialized varieties of flow probes that allow a researcher to analyze data acquired for samples in the submicrogram level. These probes include the many variants of the protasis/MRM microcoil and the inserts that one can utihze in the cryogenically cooled probes mentioned above. Both of these probes offer exceptional capabilities to acquire data on samples of very limited mass as well as very good spectral quality and reproducibility. In addition, the utilization of the smaller cell volumes also requires less effort in the experimental set-up around the suppression of residual solvent inherent in the samples of this size. 

Figure 6.45 Microbore LC-NMR layout. A Microbore HPLC system with a 0.5 mm X 150 mm C18 column is interfaced to a solenoidal microcoil probe. The transfer capfllary is connected to the NMR flow cell with a polyamide resin. Reproduced from [85] with permission. Copyright 1999 American Chemical Society.

Figure 10 (A) H NMR spectrum of the trace impurity sample (200 pM atenolol and 200 mM sucrose in 50% TE/D20) from 5-mm probe. The expanded and vertically increased area is shown. Microcoil H NMR spectra shown in (B)-(D) recorded and processed with identical parameters. (B) Static NMR spectrum obtained with direct injection of 25 mM atenolol to the NMR microcoil. S/N of atenolol methyl peak is 21. (C) On-flow cITP-NMR spectrum of atenolol sample band at peak maximum during analysis of the trace impurity sample (200 pM atenolol and 200 mM sucrose in 50% TE/D20). No sucrose peaks can be observed. S/N atenolol methyl peak is 34. (D) Stopped-flow cITP-NMR spectrum of sucrose at peak maximum from the same experiment as in (C). (Adopted with the permission from Ref. 41. Copyright 1998 American Chemical Society.)...

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