Journal: Analytical chemistry

Article Title: Automated microflow NMR: routine analysis of five-microliter samples.

doi: 10.1021/ac050936w

Figure Lengend Snippet: Figure 2. Time course for the injection of samples in DMSO-d6 using One-Minute NMR. All samples after the first sample are loaded into the sample loop while the prior sample is in the magnet. Injector cleaning of the autosampler is imbedded in the thermal equilibration time of the probe. A 1D NOESY experiment (LC1D12) with 128 scans and automatic solvent peak identification and suppression is used for NMR data acquisition. The NMR data acquisition time of 499 s includes 368 s for data collection (128 scans) and a combined total of ∼131 s for locking, solvent peak identification, automated receiver gain setting, and data processing. The complete cycle (after the first sample) includes the transit time to move the sample from the loop to the probe flow cell (79 s), thermal equilibration of the sample in the probe (90 s), and data acquisition for an overall sample-to-sample total cycle time for these conditions of 11.1 min.

Article Snippet: In automation, NMR spectra in DMSO-d6 are acquired using a standard LC NMR Bruker release 1D NOESY pulse program with double presaturation (LC1D12).21,22 Only the tallest solvent peak, usually residual water in the push solvent, is automatically identified and suppressed using low-power presaturation pulses.

Techniques: Injection, Solvent

Journal: Analytical chemistry

Article Title: Automated microflow NMR: routine analysis of five-microliter samples.

doi: 10.1021/ac050936w

Figure Lengend Snippet: Figure 6. Automatically acquired proton spectra of the same compounds as in Figure 5, but dissolved in protonated DMSO. 10 µL of 20 mM solutions was submitted in a low-volume, 384-well plate. Each spectrum was acquired with 128 scans and with a cycle time of 10.5 min between samples. The residual water and DMSO peaks at ∼3.4 and 2.5 ppm, respectively, were automatically identified and suppressed using shaped pulses in a 1D NOESY pulse sequence and 13C decoupling during acquisition. The average receiver gain was 119 and for the tallest peak between 5 and 8 ppm; the average S/N was 93. See Experimental Section for additional details.

Article Snippet: In automation, NMR spectra in DMSO-d6 are acquired using a standard LC NMR Bruker release 1D NOESY pulse program with double presaturation (LC1D12).21,22 Only the tallest solvent peak, usually residual water in the push solvent, is automatically identified and suppressed using low-power presaturation pulses.

Techniques: Sequencing