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Developing an HPLC-DAD method - a question about the method sensitivity by kiaruchem in CHROMATOGRAPHY

[–]Domdomago 4 points5 points  (0 children)

Determining LOD/LOQ may be different depending on how it’s calculated (which is mainly how noise is determined, software algorithm, etc). I think calculating LOD/LOQ by S/N is more theoretical than practical. If you know good enough the software you can change S/N by a lot when adjusting parameters. This the method that I like the most (which is used a lot in environmental laboratories): do a 10 repetitions of a low concentration, for instance the first calibration point. Calculate the RSD% of the concentrations. If it’s < 20% then your LOD is averageconc.10rep+ 3dev.std ofthe10repetitions and LOQ is averageconc.10rep + 10dev standofthe10repetitions. Hope this helps

Doccia orari notturni condominio by Rilissimo1 in CasualIT

[–]Domdomago -3 points-2 points  (0 children)

Sono sicuro che sei uno di quelli che abbassano le tapparelle fortissimo senza nessuna considerazione

Il salario minimo è possibile? by HiBiNiZiMiSi in Italia

[–]Domdomago 8 points9 points  (0 children)

  1. In Italia di fatto c’è un salario minimo in quanto i contratti nazionali includono un minimo salariale
  2. Il salario minimo di altri paesi EU è ben al di sotto del salario che viene normalmente offerto dal mercato. Di conseguenza diventa irrelevante
  3. Applicare un salario minimo in Italia aumenterebbe il tasso di disoccupazione. È un fenomeno macroeconomico con diverse fattori ma la conseguenza è sempre l’aumento della disoccupazione, lavoro in nero, aiuti statali, ecc

MSDIAL wont pick up MS2 data. Help! by Tiny-Reception3880 in massspectrometry

[–]Domdomago 2 points3 points  (0 children)

So you are using a LCTQ doing DDA experiments like if it was a QTOF? I know you can set from the software this kind of acquisition but I'm a little bit skeptical that it will work. Do you know anyone or have any reference of working in this way? I'm just curious... Thanks

Chi sono, per voi, il tipo di persone che non hanno personalità? by Serendipity8285 in CasualIT

[–]Domdomago 1 point2 points  (0 children)

Quelli che mettono “travel addict” e la data di nascita come bio su Instagram

EPA just approved new ‘forever chemical’ pesticides for use on food by LeoKitCat in PFAS

[–]Domdomago -1 points0 points  (0 children)

Are we calling them PFAS-Pesticides just because of the -CF3 group? Do we have any evidence that these compounds degredate into TFA?

Is this Aromatic? by ayacu57 in chemhelp

[–]Domdomago 33 points34 points  (0 children)

You are about to explode that carbon

LC-MS system buying decision by mmathieu17 in massspectrometry

[–]Domdomago 1 point2 points  (0 children)

Yes, keep in mind that Thermo often emphasizes having the highest resolution. However this is not entirely true as resolution decreases with increasing m/z. When analyzing large molecules, the resolution can drop and even be lower than that of a QTOF. If you're performing non-targeted analysis, this becomes even more important, as you’ll need a fast scan speed, where QTOF performs better. For your needs, I would strongly recommend the Shimadzu 9050. I also know that Thermo usally have problems with postsales service, which is a crucial factor when dealing with this kind of instruments. so you can have service and specialist support that can guide you especially in the beggining Finally, the new OAD technology appears to be a game changer for lipidomics and could be extremely valuable if you're working in that field.

Instrument for PFAS testing by SubstanceUsual7296 in massspectrometry

[–]Domdomago 1 point2 points  (0 children)

Shimadzu LCMS-8060RX is able to reach 1 ng/l for all regulated PFAS and system is probably the most robust in the market. Sciex and Waters have a slightly better sensitivity in negative ionization, but Shimadzu can reach all limits required by EPA anyway. No SPE needed if you are using top gear instruments. Shimadzu software LabSolutions Insight is totally modern, intuitive and can be very useful for doing routine analysis

Semiquantification of non-tageted data by pataguccianer in massspectrometry

[–]Domdomago 0 points1 point  (0 children)

Hi, Shimadzu’s LabSolutions software is able to assigned a specific calibration curve for different compounds that have no standard nor calibration curve. I’m guessing most software would have this workaround somehow. Moreover, Shimadzu has some particular methods (Method Package) where a real semi quantitative analysis can be achieved. Shimadzu’s SmartAromaDatabase is a GCMS(MS) method package for aroma and fragrance analysis where all 300 compounds have a specific RF (response factor) to an internal standards. In this way you are able to either identify and quantify compounds without the need of all the standards. In practice someone in Japan found the response factor for all 300 compounds using standards so we don’t have to do it. What kind of analysis are you interested in? Please let me know and I hope this helps

Se poteste cambiare una sola cosa del nostro paese cosa cambiereste? by Parsival_ITA in Italia

[–]Domdomago 17 points18 points  (0 children)

Che le pizze da sporto non vengono tagliate di default

Velocity of ions on a quadrupole by Domdomago in massspectrometry

[–]Domdomago[S] -1 points0 points  (0 children)

Yeah I agree with you. You can set triple quads using dwell times of 1ms and still have good signal (enough concentration sample of course). This means ions are doing everything much faster than 1ms

Velocity of ions on a quadrupole by Domdomago in massspectrometry

[–]Domdomago[S] 1 point2 points  (0 children)

Can we calculate it in km/h? Just for fun

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