Chromatography Forum

I am a technical translator from English to Japanese. Currently I am working on a medical paper handling MS. I have some questions on technical terms in MS.

1. What is "generic gradient" in the following paragraph? Is it "generic gradient [method]"?

Chromatography was performed using a generic gradient at a flow rate of 0.4 ml min-1. The mobile phase consisted of solvent A: acetonitrile in 0.1% acetic acid (2:98 v/v), and solvent B: acetonitrile in 0.1% acetic acid (80:20 v/v). The gradient conditions were as follows: 0-0.5 min 2% B, 0.5-1.0 min 2-90% B, and 1.0-3.5 min 90% B.

2. Is "Mass Spectrometer" missing in "Micromass Quattro Micro triple quadrupole (Micromass, Manchester, UK)" "Triple quadrupole" can be "Triple quadruple (mass) spectrometer" or "Triple quadruple instrument"?

LC-MS/MS analyses were performed with a Micromass Quattro Micro triple quadrupole (Micromass, Manchester, UK) coupled to an Alliance 2790 binary pump and an autosampler (Waters Corp., Milford MA).

3. I understand Micromass is a company name. Is Quattro Micro the brand name of the instrument produced by Micromass?

Thanks!

Don't know what a generic gradient means. Could mean linear gradient, but think the term should be removed and just defined the gradient more completely. Probably should also define the time for the return to the initial conditions and how long the equilibration period.

The Quattro Micro and the Alliance are both sold by Waters. Quattro Micro is the brand name. Quattro Micro triple quadrupole mass spectrometer sounds good to me..

1. "Generic gradient" means that the same gradient was used independent of the sample or specific sample contents.

2. Yes. Often "triple quadrupole" is used as an abbreviation for "triple quadrupole mass spectrometer", but it is slang and not correct.

3. Quattro Micro sounds like a brandname of Micromass. I will need to verify, if the nomenclature is correct. You should also be able to find it on the Micromass website.

Hi All:
Thank you for your comments.


I have another question.

I have troubles with “low-mass resolution" and "high-mass resolution".

"The analysers were set as follows: the low- and high-mass resolutions on both quadrupoles were set at 13.0 (approximately 0.9 amu FWHM) with ion energy of 1V. "

Do the authors describe two mass spectrometers, high-resolution mass spectrometer and low-resolution mass spectrometer? And, do the authors say that the both "mass resolutions" were set at 13 with ion energy of 1V?

Are there technical terms "low-mass resolution" and "high-mass resolution"?

Thanks!


The following is original paragraph.

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Electrospray ionization in both positive and negative mode (ESIt/ESI_) with multiple reaction monitoring (MRM) was used. The capillary voltage was set to 3.2 kV and the source block and desolvation temperatures were set at 130 and 300°C, respectively. The nebulizer gas was set to maximum, the cone and desolvation gas were set to 70 and 680 l h-1, respectively (high purity nitrogen). The analysers were set as follows: the low- and high-mass resolutions on both quadrupoles were set at 13.0 (approximately 0.9 amu FWHM) with ion energy of 1V. The collision entrance and exit lenses were -2 and 1V, respectively. High-purity argon was used as a collision induced dissociation (CID) gas. The CID gas was adjusted to give a collision cell pressure of approximately 2.1 e-3 mBar.

I am not sitting in front of my instrument right now, but I believe the instrument has a low mass resolution and a high mass resolution setting. Usually the engineer sets up the instrument to insure the specifications for resolution are met (0.7 amu) with a setting of 15 on both settings. By decreasing the value to 13 on both settings, you decrease the resolution and increase the sensitivity.

However, these settings are somewhat arbitrary, so I think it would be adequate to indicate the values chosen gave a value of approximately 0.9 amu FWHM..