Webcan leach contamination into the LC solvent. A thorough cleaning procedure is listed at the end of this document. Phthalate Contamination (391, 413 798, 803) 391 protonated dioctyl phthalate (M+H)+. 413 sodium adduct of dioctyl phthalate (M+Na)+. 798 ammoniated dimer of dioctyl phthalate [2M+NH4]+. Web22 feb. 2012 · ZeroAir. The only thing I can think of is. ammonium ion/NH4+ is 18 AMU. If M= 354 (M+H is 355) then M+NH4+ would be 372. You state you are only using water/MeOH/Chloroform and TFA so where would the ammonium be coming from, (your system might be saturated with it). It might also be a background contaminant.
M + 18 ion in ESI... water? - Chromatography Forum
WebSteroids give the greatest sensitivity in negative ion with adduct formation. In general sodium adducts for quantification are difficult due to variable response and the difficulty of... Web1 apr. 2016 · Homocysteine is a nonessential, sulfur-containing amino acid involved in one-carbon (folate) metabolism. A number of inherited and acquired conditions cause increased accumulation of this metabolite in blood (homocysteinemia) and other biofluids. Homocysteinemia is a risk factor for cardiovascular d … bungalows for sale in twickenham middx
Evaluation of Different Ion Pairing Reagents for LC/UV and LC/MS ...
http://tmsdatabase.org/public/frm_aductioncalc.aspx WebThis calculator allows to identify some adduct ions from ESI-MS (electrospray) mass spectrometry measurements or other soft ionization techniques like CI-MS or FI-MS … WebThis application note demonstrates an automated, compliance-ready liquid chromatography-mass spectrometry (LC-MS) worflow for intact mass confirmation and purity analysis of synthetic oligonucleotides including small interfering RNA (siRNA) and large single guide (sg) RNA oligonucleotides and their impurities. half scholarship meaning