Ion funnel quadrupole time of Flight mass spectrometry: optimization for achieving all ion MS/MS and pseudo MSn

An attempt has been made to study and understand Ion funnel technology for improved detection and measurement capabilities of ions originating from small molecules. Different ways to create and study collision induced fragments have been explored and strategies to achieve various kinds of all ions MS/MS have been discussed. We observed that stability of ions in the system is largely controlled by the funnel exit DC voltage and Rf voltages of the low pressure funnel also contributes to the collision induced dissociation of the ions. An appropriate mix of in source collision energy coupled with Funnel exit DC voltage and low pressure funnel Rf voltage can induce extensive fragmentation of the ions mimicking several stages of MS/MS simultaneously

A proposal for a protocol for prevention and control of Coronavirus (COVID-19)

Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory coronavirus-2 (SARS-CoV-2), is an extremely infectious disease and has already infected almost three million persons in more than two hundred countries. Based on our current knowledge of this virus and in absence of a vaccine, this article is an attempt to propose out of box ways to prevent and control COVID-19 virus, using linear lipid molecules such as sodium stearate (a major component of ordinary bar soap) or lipid esters for hand sanitization, mouth wash, gargling, steam inhaling and as lungs inhaler along with zinc and copper to trap and inactivate COVID-19. Sunbathing will boost desperately needed good immune system. The ancient Indian techniques of Yoga (Developing inherent power in a balanced manner), Pranayama (Retention and Extension of the breath), Jal-Neti (Nasal irrigation by saline water) and Havan (Holy fire ritual) may also help in controlling this epidemic (COVID-19) of gargantuan proportions by helping the immune system

Transformation of 17a-methyltestosterone in aquatic-sediment systems

Two sediment samples that differed with respect to total organic carbon and texture (“sand” and “clay”) were exposed to radio inert 17a-methyltestosterone (MT) or [14C]-radiolabeled 17a-methyltestosterone (14C-MT), under both aerobic and anaerobic conditions, for up to 56 days, to characterize the fate of MT in the aquatic environment. Radio inert MT was quantified by a highly sensitive liquid chromatography/mass spectrometry (LCMS) method and radioactive MT was quantified by HPLC using an in-line flow liquid scintillation counter (LSC). Thedata suggest that MT entering the aquatic environment is converted into metabolites that become tightly associated with the sediment. Half-lives for MT dissipation in the sediment systems ranged from 2-9 days, depending on the sediment type and the presence of oxygen. Sediment type had little effect on MT dissipation. The mineralization of MT under aerobic conditions was low (<9% conversion of MT to CO2)

Controlling formation of metal ion adducts and enhancing sensitivity in Liquid Chromatography Mass Spectrometry

Formation of metal ion adducts in mass spectrometry, particularly in electrospray ionization liquid chromatography mass spectrometry (ESI-LC-MS), is a nightmare scenario for an analyst dealing with quantitative analysis. We have studied in detail the metal adduct formation and concluded  that the use of fluorinated alkanoic acids along with formic acid and volatile ammonium salts was extremely useful in suppressing metal adduct formation in positive ion mode of ESI-LC-MS. The extremely high electronegativity of fluorine atom and unique electrostatic nature of C—F bond coupled with stereo-electronic interactions with neighboring bonds or lone pairs enables the polyfluorinated alkanoic acids in trapping highly electropositive ions (Na+, K+) thereby letting proton do its job efficiently. Addition of formic acid, trifluoroacetic acid, heptafluorobutyric acid and ammonium acetate was found to be extremely effective in controlling metal ion adducts and producing [M+H]+ ions almost exclusively resulting in significant increase in the sensitivity. This technique has been successfully used in our laboratory for the estimation of targeted and nontargeted analysis of pesticides, marine toxins, drugs and pharmaceuticals etc. in various matrices including environmental waters using liquid chromatography-time of flight mass spectrometer operated in all ion acquisition mode and triple quadruples (QQQ) in multiple reaction monitoring (MRM) mode

Development and validation of a High performance liquid chromatography- Mass spectrometry method for 17a-methyltestosterone in Aquatic water systems

17a-Methyltestosterone is used as feed additive to manipulate the gender of fish for aquaculture. Earlier a simple, yet specific and robust validated high performance liquid chromatographic method has been developed for the determination of 17a-methyltestosterone in fish feed. The present work describes a highly sensitive and robust Liquid Chromatography-Mass Spectrometry method for the quantitation of 17a-methyltestosterone in aquatic water systems using 17â-hydroxy-3â-methoxyandrost-5-en-7-one as internal standard. The method was validated in the concentration range of 0.2 to 25 ng of 17a-methyltestosterone on column leading to a limit of quantitation of 0.08 ppb or 0.08 mg/L in water, and has potential to increase the limit of detection and quantitation by an order of magnitude, if required

Targeted and non-targeted analysis of organic compounds of moderate polarity in water using liquid chromatography-time of flight mass spectrometry in all ion mode with particular reference to analysis of pesticides

We have developed a novel yet efficient method for the multi residue analysis of organic compounds of diverse polarities in water using Liquid Chromatography-Time of Flight mass spectrometry (LC-MS-TOF) equipped with a jet stream Electrospray ionization (ESI) source. Use of three different fragmentor voltages (low, medium and high) enabled the qualitative and quantitative analysis of a diverse range of targeted organic compounds in environmental waters. No prior optimization of compounds being quantified was required, the limiting factors were ionization behaviour of compounds under conditions of ESI and good chromatography. Same data file could be subjected to repeated post-run data analysis to figure out the presence of non-targeted compounds, including designer drugs if any. The technique has been illustrated with reference to a group of pesticides having diverse chromatographic and ionization behaviours. The optimized Solid Phase Extraction (SPE)  followed by method validation yielded a robust yet simple quantitative method for a group of fourteen pesticides. We were able to achieve quantitation at 10 ng/L or lower depending upon ionization behaviour of substrates against the usual regulatory requirement of 1000 ng/L. The method was used for targeted and non-targeted detection of pesticides in Nueces estuary waters, TX, USA, and several untargeted pesticides, pharmaceuticals and personal care products were identified