The 6545 is a midrange instrument - meaning it is likely to be used for routine analyses and is designed to be a workhorse for reliability and robustness, while delivering sensitivity, dynamic range, mass resolution and mass accuracy.
It is engineered to be Agilent’s most reliable Q-TOF, building on LC/MS reliability and adding hardware advances such as ion shaping optics, high-voltage power supplies and longer-life parts.
Hardware and software improvements make it more reliable and easier to use for trace-level analysis of small-molecule compounds in food safety and pharmaceuticals.
Looking for unknowns
David Edwards, senior director of MS marketing, told us it’s becoming more common to look for unknowns in food safety as more people get accurate mass instruments.
“An example is to look for pesticides that are no longer regulated or not anticipated to appear in a food product. You’d also do that for drugs in food (veterinary drugs, etc.)," he said.
“There are also possibilities that mycotoxins that are not regulated could be present in food and create safety issues.
“Contaminants such as melamine, which were not targeted, and became a big health threat, have raised awareness of the need to screen for unknown contaminants, so it is a growing trend to use TOF and Q-TOF instruments in food and environmental testing."
Agilent said it addresses a key need in the market to make high performance results more accessible to all skill levels.
The Q-TOF is basically an LC/MS/MS, Edwards added.
“People often refer to LC/MS/MS related to QQQ [triple quadrupole mass spectrometry] analysis, as you can do isolation and then fragmentation and get an MS/MS spectra on a QQQ," he said.
“However, the QQQ is used generally for targeted compounds at trace levels. The most common use is to go after known contaminants and to screen for those in a routine manner.
“If looking for other compounds that are not targeted, or for both targeted and non-targeted, you can use the Q-TOF.”
System specs
Agilent said sensitivity in MS mode, electrospray on-column, 400 μL/min flow rate is 500:1 root mean square (RMS). In MS/MS mode, it is 1,500:1 RMS.
Mass resolving power is greater than 45,000 full width at half maximum (FWHM) at m/z 2,722.
Mass accuracy in MS mode is less than 0.8 ppm RMS as measured from 10 repeat injections; in MS/MS mode, it is less than 2 ppm RMS on m/z 397 from the same measurement.
Mass range is m/z 100–10,000 extended mass range and m/z 50–1,700 or 50–3,200 for high resolution and extended dynamic range modes; Quadrupole up to m/z 4,000.
Dynamic range is up to 5 decades, acquisition speed is 50 spectra/second in MS mode and 30 MS/MS spectra/second in MS/MS mode and positive to negative switching can be done in 1.5 seconds.
Particle swarm technology
The system’s autotune software uses particle swarm technology to optimize it for small-molecule analyses with the click of a button. In 15 minutes, it can get up to five times more sensitivity for small molecule compounds, including low-intensity compounds.
Particle Swarm Optimization (PSO) is a multidimensional optimization algorithm that can optimize up to 21 parameters simultaneously – even when no initial signal is present – and can avoid getting trapped in a local optima.
“It can optimize elements for a target resolution, level of fragmentation, or for maximum sensitivity with a simple “start tune” button," said Edwards.
“The Swarm Autotune applies the principles of PSO to simplify the optimization of multiple instrument parameters and is adjusted to allow for more ion transmission, more speed and lower loss of fragile molecules.
“What this means for the user is that the autotune is four times faster than previous generation Q-TOFs, and it automatically delivers enhanced sensitivity for the best small molecule performance, so everyone can get great, optimized results easily.”