A liquid chromatography electrospray ionization tandem mass spectrometry method for quantification of up to eighteen cannabinoids in hemp-derived products.

A LC-ESI/MS/MS method was developed for quantification of up to eighteen cannabinoids, the maximum number published so far. A thorough study of published LC-ESI/MS/MS methods using triple quadrupole mass spectrometers revealed a possible misconception that multiple reaction monitoring (MRM) was able to definitively differentiate structural isomers of cannabinoids, especially Δ-/Δ-tetrahydrocannabinol (THC), which explained why many of those methods were developed for a limited number of cannabinoids, as small as two, and did not include Δ-THC. In this study, the use of a quadrupole time-of-flight (QTOF) mass spectrometer for targeted analysis indicated that MRM could not definitively distinguish structural isomers of Δ-THC, with a possible exception of cannabicyclol (CBL) for less accurate quantification, so their baseline separation was essential for their accurate quantification.

Potency testing of up to sixteen cannabinoids in hemp-infused edibles using liquid chromatography diode array detector with optional confirmation of identity by electrospray ionization time-of-flight mass spectrometry.

A LC-DAD method for potency testing of up to sixteen cannabinoids has been developed, validated, and applied for analysis of twenty hemp-infused edibles encompassing a broad range of complex matrices. The method was validated according to ISO 17025 guidelines and met requirements. Samples or their uniform water-dispersions were extracted by methanol under homogenization through pulverization and/or ultrasonication.

A Novel Method Based on Hydrodynamic Cavitation for Improving Nitric Oxide Removal Performance of NaClO.

In the removal of nitric oxide (NO) by sodium chlorite (NaClO), the NaClO concentration is usually increased, and an alkaline absorbent is added to improve the NO removal efficiency. However, this increases the cost of denitrification. This study is the first to use hydrodynamic cavitation (HC) combined with NaClO for wet denitrification.

MicroRNA-489-3p aggravates neuronal apoptosis and oxidative stress after cerebral ischemia-reperfusion injury.

Cerebral ischemia-reperfusion injury (CIRI) mostly occurs in the treatment stage of ischemic diseases and aggravate brain tissue damage. Although studies have demonstrated that miR-489-3p is closely related to CIRI, the effects of miR-489-3p on neural function in CIRI have not been directly studied. The transient middle cerebral artery occlusion (tMCAO) model was established by suture method, and the corresponding plasmids that interfered with the expression of miR-489-3p or Sirtuin1 (SIRT1) were injected into the model mice, and the behavioral changes of the mice were observed.

Potency testing of up to twenty cannabinoids by liquid chromatography diode array detector with optional electrospray ionization time-of-flight mass spectrometry.

The growing popularity of Cannabis sativa L. and its widespread use for medical and recreational purposes have created an urgent demand of accurate and reliable analytical methods to identify and quantify a growing number of cannabinoids. To meet this demand, a liquid chromatography diode array detector (LC-DAD) method has been developed, validated, and applied in analysis of cannabinoids in nine samples of plant materials of marijuana, six samples of marijuana cigarettes, five samples of hemp flowers, one sample of hemp cigarette, and two samples of Δ-tetrahydrocannabinol (Δ-THC) fortified hemp flowers.

Development of a validated method for rapid quantification of up to sixteen cannabinoids using ultra-high-performance liquid chromatography diode-array detector with optional electrospray ionization time-of-flight mass spectrometry detection.

Due to the recent legalization of medical and recreational Cannabis in many countries in the world, there has been an increasing demand for accurate quantification of a growing number of cannabinoids. To meet this challenge, a method for rapid quantification of up to sixteen cannabinoids using ultra-high-performance liquid chromatography diode-array detector (UHPLC-DAD) has been developed, validated and used in the analysis of hemp concentrates. While published LC-UV methods were usually for twelve or less cannabinoids and might not achieve baseline separation of some critical pairs of cannabinoids, e.

Insight into the promoting effect of support pretreatment with sulfate acid on selective catalytic reduction performance of CeO/ZrO catalysts.

In this paper, sulfated ZrO were synthesized via precipitation and impregnation method, and the promoting effects of support sulfation on selective catalytic reduction (SCR) performance of CeO/ZrO catalysts were investigated. The results revealed that sulfated ZrO could significantly enhance the SCR activity of CeO/ZrO catalysts in a wide temperature range. Especially when S/Zr molar ratio was 0.

Leguminous supplementation increases the resilience of soil microbial community and nutrients in Chinese fir plantations.

Understory vegetation plays a vital role in the flow of materials and nutrient cycling in plantation ecosystems. Introducing functional plants (one species or a group of plants that share similar characteristics and can play a similar role in an ecological environment) can quickly improve the environment of the soil of a plantation with a single-stand structure suffering from soil degradation. Five stands composed of Chinese fir plants of different ages (young, immature, near-mature, mature, and over-mature stand forests) were supplemented with leguminous plants to determine the effects on soil nutrients and microbial communities.

Nitrogen direct analysis in real time time-of-flight mass spectrometry (N DART-TOFMS) for rapid screening of forensic drugs.

Rationale: Over the last ten years, helium direct analysis in real time time-of-flight mass spectrometry (He DART-TOFMS) has become an established technique in rapid screening of forensic drugs to decrease the time necessary to triage forensic drug cases, therefore contributing to backlog reduction and more timely criminal prosecution. Recently, we demonstrated that N DART was able to efficiently ionize all polar compounds except for a few extremely small ones such as methanol and acetonitrile. Therefore, N DART-TOFMS should be a suitable technique for rapid screening of forensic drugs.

Ionization Mechanism of Positive-Ion Nitrogen Direct Analysis in Real Time.

Nitrogen can be an inexpensive alternative to helium used by direct analysis in real time (DART), especially in consideration of the looming helium shortage. Therefore, the ionization mechanism of positive-ion N DART has been systematically investigated. Our experiments suggest that a range of metastable nitrogen species with a variety of internal energies existed and all of them were less energetic than metastable helium atoms.

Quantitative real-time monitoring of chemical reactions by autosampling flow injection analysis coupled with atmospheric pressure chemical ionization mass spectrometry.

Although qualitative and/or semiquantitative real-time monitoring of chemical reactions have been reported with a few mass spectrometric approaches, to our knowledge, no quantitative mass spectrometric approach has been reported so far to have a calibration valid up to molar concentrations as required by process control. This is mostly due to the absence of a practical solution that could well address the sample overloading issue. In this study, a novel autosampling flow injection analysis coupled with an atmospheric pressure chemical ionization mass spectrometry (FIA/APCI-MS) system, consisting of a 1 μL automatic internal sample injector, a postinjection splitter with 1:10 splitting ratio, and a detached APCI source connected to the mass spectrometer using a 4.

Differentiation of underivatized monosaccharides by atmospheric pressure chemical ionization quadrupole time-of-flight mass spectrometry.

Rationale: Differentiation of underivatized monosaccharides is essential in the structural elucidation of oligosaccharides which are closely involved in many life processes. So far, such differentiation has been usually achieved by electrospray ionization mass spectrometry (ESI-MS). As an alternative to ESI-MS, atmospheric pressure chemical ionization mass spectrometry (APCI-MS) should provide complementary results.

Evaluation of direct analysis in real time mass spectrometry for onsite monitoring of batch slurry reactions.

Batch slurry reactions are widely used in the industrial manufacturing of chemicals, pharmaceuticals, petrochemicals and polymers. However, onsite monitoring of batch slurry reactions is still not feasible in production plants due to the challenge in analyzing heterogeneous samples without complicated sample preparation procedures. In this study, direct analysis in real time mass spectrometry (DART-MS) has been evaluated for the onsite monitoring of a model batch slurry reaction.

Ionization mechanism of positive-ion direct analysis in real time: a transient microenvironment concept.

A transient microenvironment mechanism (TMEM) is proposed to address matrix effects for direct analysis in real time (DART). When the DART gas stream is in contact with the sample, a transient microenvironment (TME), which can shield analytes from direct ionization, may be generated through the desorption of the matrix containing the analyte. The DART gas stream can directly ionize the matrix molecules, but the analytes will be ionized primarily through gas-phase ion/molecule reactions with the matrix ions.

Liquid chromatography/negative ion atmospheric pressure photoionization mass spectrometry: a highly sensitive method for the analysis of organic explosives.

Gas chromatography/mass spectrometry (GC/MS) is applied to the analysis of volatile and thermally stable compounds, while liquid chromatography/atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) and liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) are preferred for the analysis of compounds with solution acid-base chemistry. Because organic explosives are compounds with low polarity and some of them are thermally labile, they have not been very well analyzed by GC/MS, LC/APCI-MS and LC/ESI-MS. Herein, we demonstrate liquid chromatography/negative ion atmospheric pressure photoionization mass spectrometry (LC/NI-APPI-MS) as a novel and highly sensitive method for their analysis.

Ionization mechanism of negative ion-direct analysis in real time: a comparative study with negative ion-atmospheric pressure photoionization.

The ionization mechanism of negative ion-direct analysis in real time (NI-DART) has been investigated using over 42 compounds, including fullerenes, perfluorocarbons (PFC), organic explosives, phenols, pentafluorobenzyl (PFB) derivatized phenols, anilines, and carboxylic acids, which were previously studied by negative ion-atmospheric pressure photoionization (NI-APPI). NI-DART generated ionization products similar to NI-APPI, which led to four ionization mechanisms, including electron capture (EC), dissociative EC, proton transfer, and anion attachment. These four ionization mechanisms make both NI-DART and NI-APPI capable of ionizing a wider range of compounds than negative ion-atmospheric pressure chemical ionization (APCI) or negative ion-electrospray ionization (ESI).

Evaluation of ceftazidime contents in antibiotic discs by capillary electrophoresis.

Good quality of antibiotic discs is a fundamental prerequisite to accurate antibiotic susceptibility tests. Capillary electrophoresis (CE) is a widely used method for quantitative analysis. Here, using ceftazidime as an example, we report an easy-to-perform strategy to determine ceftazidime content in discs.

[Determination of alachlor residue in agricultural products].

A method of the determination of alachlor residue in agricultural products was developed. Four different kinds of objects, corn, peanut, spinach, and orange were selected as representatives of main agricultural products. The sample was extracted with acetone-water (8:2, v/v).

Negative ion-atmospheric pressure photoionization: electron capture, dissociative electron capture, proton transfer, and anion attachment.

To better guide the development of liquid chromatography/electron capture-atmospheric pressure photoionization-mass spectrometry (LC/EC-APPI-MS) in analysis of low polarity compounds, the ionization mechanism of 19 compounds was studied using dopant assisted negative ion-APPI. Four ionization mechanisms, i.e.

Electron capture atmospheric pressure photoionization mass spectrometry: analysis of fullerenes, perfluorinated compounds, and pentafluorobenzyl derivatives.

An electron capture (EC) ionization mechanism has been found to be highly efficient in negative-ion atmospheric pressure photoionization (APPI) for the analysis of compounds with positive electron affinity (EA). Using negative-ion APPI, we first report the sensitive detection of natural electrophores with limited polarity, such as fullerenes and perfluorinated compounds, by mass spectrometry (MS). Using direct infusion on a quadrupole time-of-flight (QTOF) mass spectrometer, the limits of detection (LODs) for C(60) and perfluoromethylcyclohexane were determined to be 0.

The principal urinary metabolites of dietary isothiocyanates, N-acetylcysteine conjugates, elicit the same anti-proliferative response as their parent compounds in human bladder cancer cells.

Isothiocyanates (ITCs) are a class of well-known cancerpreventive phytochemicals, but are primarily disposed of and concentrated in the urine as N-acetylcysteine conjugates (NAC-ITCs) in vivo. Because human urinary bladder cancers occur almost exclusively in the bladder epithelium, which is directly exposed to the urine stored in the bladder, we undertook to examine the anti-cancer activity of NAC-ITCs in cultured human bladder cancer cells. In this paper, we report that the NAC conjugates of four naturally occurring ITCs, including allyl ITC, benzyl ITC (BITC), phenethyl ITC and sulforaphane, potently inhibited the growth of cells derived from both low-grade superficial and high-grade invasive human bladder cancers and drug-resistant bladder cancer cells.

Analysis of human plasma proteome by 2DE- and 2D nanoLC-based mass spectrometry.

We compared the 2DE coupled to MALDI-TOF-MS and ESI-MS/MS analysis (2DE-MS) and the on-line 2D nanoLC, followed by nanoESI-MS/MS analysis (2DLC-MS), for the separation and identification of proteins in high abundance protein-depleted human plasma. Identification of proteins in the plasma by the two methods demonstrated that the majority of the identified protein set was unique to each method. Therefore, if a comprehensive coverage of the proteome identification is desired, it is ideal to apply both methods.

Early evidence on the effectiveness of clean indoor air legislation in New York State.

In July 2003, New York State implemented the Clean Indoor Air Act (CIAA) to reduce exposure to environmental tobacco smoke (ETS). In this cross-sectional study, workers (n=168) completed an interview assessing ETS exposure and provided urine for cotinine analysis. Hospitality workers recruited after implementation of the CIAA had significant reductions in ETS exposure and urine cotinine, compared with those recruited before implementation.

Pharmacokinetic measurements of IDN 5390 using electrospray ionization tandem mass spectrometry: structure characterization and quantification in dog plasma.

In this report, electrospray ionization tandem mass spectrometry (ESI-MS/MS) for a pharmacokinetic study of IDN 5390, a novel C-seco taxane derivative, which is under preclinical evaluation, has been investigated. Our results showed that IDN 5390 and other taxanes including paclitaxel and IDN 5109 could ionize well in not only positive-, but also in negative-ion mode. Under collision-induced dissociation (CID) conditions, these compounds could fragment into similar M- (molecular), T- (taxane ring) and S- (side chain) series ions.

Specific method for the determination of genomic DNA methylation by liquid chromatography-electrospray ionization tandem mass spectrometry.

Herein we report a novel method for determining genomic DNA methylation that utilizes liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to measure 5-methyl-2'-deoxycytidine levels following enzymatic hydrolysis of genomic DNA. LC separation of 5-methyl-2'-deoxycytidine from the four deoxyribonucleosides, the four ribonucleosides, and 5-methyl-2'-cytidine, a RNA methylation product, has been achieved within 15 min. In combination with ESI-MS/MS detection, the reported method is highly specific and extremely sensitive with a limit of detection (LOD) of 0.