Trap Tandem Mass Spectrometry Method Research Articles

Novel Isotope Dilution High-Performance Liquid Chromatography Quadrupole–Linear Ion Trap Tandem Mass Spectrometry Method for the Determination of Five Steroid Hormones in Human Serum

Accurate measurement of endogenous steroid hormones in serum is a powerful tool for understanding the status of human adrenal diseases. Isotope dilution–liquid chromatography–tandem mass spectrometry is the most commonly used method for determination of steroids in serum. In this study, we used a laboratory-constructed quadrupole-linear ion trap (Q-LIT) tandem mass spectrometer to develop a new method for the quantification of five steroid hormones in serum. A simple and efficient pretreatment was improved, wherein the serum was extracted once by a mixed solvent of 1.0 mL of ethyl acetate and n-hexane. Using the optimized method, the regression coefficients of the calibration curves were all higher than 0.99, the limits of detection were from 0.31 to 1.25 ng mL−1, and the limits of quantification were between 1.00 and 2.50 ng mL−1. The intra-day (n = 3) relative standard deviations ranged from 4.24% to 13.79%, and the inter-day (n = 3) relative standard deviations from 3.99% to 11.43%. After internal standard correction, the relative recoveries of all steroids were from 86.08% to 106.60%. Twenty-two serum samples were analyzed by Q-LIT, which was compared with commercial triple quadrupole mass spectrometer. The results of the instruments had high consistency. Therefore, Q-LIT accurately quantified steroid hormones in human samples and may be used for clinical diagnosis and monitoring of hormone-dependent diseases.

Istamycin aminoglycosides profiling and their characterization in Streptomyces tenjimariensis ATCC 31603 culture using high‐performance liquid chromatography with tandem mass spectrometry

A high-performance liquid chromatography with electrospray ionization ion trap tandem mass spectrometry method was developed and validated for the robust profiling and characterization of biosynthetic congeners in the 2-deoxy-aminocyclitol istamycin pathway, from the fermentation broth of Streptomyces tenjimariensis ATCC 31603. Gradient elution on an Acquity CSH C18 column was performed with a gradient of 5mM aqueous pentafluoropropionic acid and 50% acetonitrile. Sixteen natural istamycin congeners were profiled and quantified in descending order; istamycin A, istamycin B, istamycin A0 , istamycin B0 , istamycin B1 , istamycin A1 , istamycin C, istamycin A2 , istamycin C1 , istamycin C0 , istamycin X0 , istamycin A3 , istamycin Y0 , istamycin B3 , and istamycin FU-10 plus istamycin AP. In addition, a total of five sets of 1- or 3-epimeric pairs were chromatographically separated using a macrocyclic glycopeptide-bonded chiral column. The lower limit of quantification of istamycin-A present in S. tenjimariensis fermentation was estimated to be 2.2ng/mL. The simultaneous identification of a wide range of 2-deoxy-aminocyclitol-type istamycin profiles from bacterial fermentation was determined for the first time by employing high-performance liquid chromatography with tandem mass spectrometry analysis and the separation of istamycin epimers.

Matrix-Matching as an Improvement Strategy for the Detection of Pesticide Residues.

More than 90% of the pesticides residues in apples are located in the peel. We developed a gas chromatography/ion trap tandem mass spectrometry method for investigating all detectable residues in the peel of 3 apple varieties. Sample preparation is based on the use of the Quick Easy Cheap Effective Rugged and Safe method on the whole fruit, the flesh, and the peel. Pesticide residues were quantified with solvent-matched and matrix-matched standards, by spiking apple sample extracts. Matrix effects dependent on the type of extract (fruit, flesh, or peel) and the apple variety were detected. The best data processing methods involved normalizing matrix effect rates by matrix-matched internal/external calibration. Boscalid, captan, chlorpyrifos, fludioxonil, and pyraclostrobin were the most frequently detected pesticides. However, their concentrations in the whole fruit were below European maximum residue levels. Despite negative matrix effects, the residues in peel were detected at concentrations up to 10 times higher than those in whole fruits. Consequently, other pesticide residues present at concentrations below the limit of quantification in the whole fruit were detected in the peel.

Validation of a Gas Chromatography–Ion Trap-Tandem Mass Spectrometry Assay for the Simultaneous Quantification of Cocaine, Benzoylecgonine, Cocaethylene, Morphine, Codeine, and 6-Acetylmorphine in Aqueous Solution, Blood, and Skeletal Muscle Tissue

A gas chromatography-ion trap-tandem mass spectrometry method was developed and validated for the simultaneous solid-phase extraction and quantification of cocaine, benzoylecgonine, cocaethylene, morphine, codeine, and 6-monoacteylmorphine in blood, muscle tissue, and water. An assay for total morphine in blood and muscle was also validated. The limit of quantification was ≤ 0.01 mg/kg in muscle and ≤ 0.005 mg/L in blood and water. Good linearity was observed over the concentration ranges studied (r ≥ 0.99). The repeatability (% RSD) at the three concentration levels was typically ≤ 15% and never exceeded 17%. Intermediate precision of ≤ 16% was obtained for all matrices. Deviation < 20% of the nominal concentration was obtained in all repeatability and intermediate precision experiments. Extraction recoveries for cocaine and metabolites ranged from 91% to 110% in water, 81% to 110% in blood, and 61% to 75% in muscle. Recoveries for opiates ranged from 59% to 104% in water, 50% to 95% in blood, and 41% to 79% in muscle. The hydrolysis efficiency for the total morphine assay in blood and muscle ranged from 91% to 99% with within-day and intermediate precisions of ≤ 14% and ≤ 12%, respectively.

A solid‐phase microextraction gas chromatography/ion trap tandem mass spectrometry method for simultaneous determination of ‘foxy smelling compounds’ and 3‐alkyl‐2‐methoxypyrazines in grape juice

2'-Aminoacetophenone (o-AAP) was identified as the main cause of the aging note called 'hybrid note' or 'foxy smell' which is typical of non-Vitis vinifera grapes. Together with methyl anthranilate (MA), this compound contributes to the typical foxy taint of wines made with non-Vitis vinifera grapes. 3-Alkyl-2-methoxypyrazines in grapes, with their herbaceous note and very low sensory thresholds, contribute to the aroma of several wines. In this study, a solid-phase microextraction gas chromatography/ion trap tandem mass spectrometry (SPME-GC/IT-MS/MS) method for simultaneous detection of o-AAP, MA and ethyl-, isopropyl-, sec-butyl- and isobutylmethoxypyrazine in grape juice was developed. The method was applied to the study of several grape juices: the time required for analysis was less than 24 min, and the method was considered to be suitable for analysis of 'foxy compounds' and methoxypyrazines in grape juice. The high levels of MA and o-AAP found in Clinton and Siebel grapes confirmed the 'hybrid' character of these varieties.

Gas chromatography–ion trap tandem mass spectrometry method for the analysis of methoxylated polybrominated diphenyl ethers in fish

Gas chromatography coupled to ion trap tandem mass spectrometry (GC–ITMS-MS) is proposed for the analysis of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) in fish and shellfish. MS–MS operating parameters related to the isolation and fragmentation of the precursor ions were optimized to achieve maximum sensitivity and selectivity. This new method allows the determination of both MeO-PBDEs and PBDEs in a single run. Low limits of detection (0.4–2.5 pg injected) and high precision (RSD < 13%) were achieved. A sample treatment based on a selective pressurized liquid extraction (PLE) using Florisil as fat retainer was applied for the analysis of these compounds in fish samples. Method limits of quantification ranged from 0.11 to 0.95 ng g −1 lipid weight for MeO-PBDEs and between 0.18 and 0.50 ng g −1 lipid weight for PBDEs. In addition, good repeatability of the whole method was achieved (RSD < 15%). The suitability of the method was evaluated by analyzing a certified reference material (SRM 1945, whale blubber) with satisfactory results. The developed method was applied to the simultaneous analysis of MeO-PBDEs and PBDEs in fish and shellfish samples from the Mediterranean Sea.

HPLC COUPLED WITH ION TRAP MS/MS FOR ANALYSIS OF TERTIARY BUTYLHYDROQUINONE IN EDIBLE OIL SAMPLES

ABSTRACT A rapid, sensitive, precise and accurate quantitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the measurement of tertiary butylhydroquinone (TBHQ) in commercial edible oil was developed and validated. After extraction, samples without prior concentration were analyzed by ion trap MS/MS in MS and MS/MS negative ion detection modes using electrospray ionization. The method showed satisfactory recovery (81.9 ± 1.9–109.6 ± 4.6%), sensitivity (lower limit of quantitation of 48 µg/L for TBHQ) and precision (≤5.2%), as well as excellent linearity (R2 ≥ 0.99), with a run time of only 5 min. The method was successfully applied to the determination of TBHQ in commercial samples of edible oils containing various natural antioxidants, providing a promising and convenient entry to monitor the use of TBHQ.PRACTICAL APPLICATIONSHPLC coupled with the ion trap tandem mass spectrometry method with high selectivity, sensitivity, precision and accuracy is suitable for routine quality control analysis of tertiary butylhydroquinone (TBHQ) in edible oils. Analyzing each oil sample by this method takes only 5 min. Moreover, the evaluation of TBHQ in commercial edible oil by this method does not suffer from interference of some coexisting potential peculiar chemical components.

Headspace solid-phase micro-extraction and gas chromatography-ion trap tandem mass spectrometry method for butyltin analysis in sediments: Optimization and validation

In this work, headspace solid-phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) method for analysis of butyltin compounds in sediment samples was upgraded by the introduction of tandem mass spectrometry (MS/MS). Optimization and validation of this method based on an one step procedure, tetraethylborate in situ ethylation with simultaneous extraction by headspace SPME, combined with tandem mass spectrometry is described. A simple leaching/extraction step of mono-(M), di-(D) and tri-(T) butyltin (BT) compounds from the sediment is required as sample pre-treatment. The combination of the two techniques headspace SPME and MS/MS, led to very little matrix interference which permitted to attain limits of detection three or more orders of magnitude lower than those attained in previous methods: 0.3 pg g − 1 for MBT, 1 pg g − 1 for DBT and 0.4 pg g − 1 for TBT. Linear response range was from 0.02–1260 ng g − 1 for MBT, 0.07–1568 ng g − 1 for DBT and 0.04–2146 ng g − 1 for TBT and RSD < 15% was also obtained. The method was efficiently applied to a real sample sediment from Sado River estuary in Portugal, revealing the existence of BTs pollution, as the TBT level of 189 ± 15 ng g − 1 was much higher than the maximum established as provisional ecotoxicological assessment criteria.

Liquid Chromatography−Electrospray Ionization−Tandem Mass Spectrometry Method for the Determination of Epoxidized Soybean Oil in Food Products

Epoxidized soybean oil (ESBO) is widely used as a plasticizer and stabilizer in such polymers [poly(vinyl chloride) in particular] commonly adopted for manufacturing of gaskets of the lids for glass jars and plastic films for food packaging. Human exposure to ESBO and its derivatives is likely to occur over a lifetime with a significant variation according to life stage. A reversed phase liquid chromatography interfaced with electrospray ion trap tandem mass spectrometry method for the determination of ESBO in foods was developed. A simple sample treatment procedure entailing the use of an extraction step with dichloromethane without any further cleanup was proved. Chromatographic separation was performed using two C18 columns with an aqueous acetic acid-acetone-acetonitrile mixture as the mobile phase under gradient conditions. The method was validated in terms of detection limits (4 mg kg(-1)), quantitation limits, linearity (established over 2 orders of magnitude), recovery (good mean recoveries, higher than 90% for all of the signals detected), precision (RSD% < 8), and trueness. The applicability of the method to the determination of ESBO in different food matrices (in particular those rich in edible oil) was demonstrated, and the performances were compared to those reachable by the commonly well-known gas chromatography-mass spectrometry procedure.

Workplace monitoring of isocyanates using ion trap liquid chromatography/tandem mass spectrometry.

A sensitive liquid chromatography/ion trap tandem mass spectrometry method was developed for the qualitative and quantitative detection of isocyanates in air. The method is based on derivatization of isocyanates with 1-(2-methoxyphenyl)piperazine during air sampling. The extracts are analyzed using an ion trap LC/MS system equipped with an electrospray (ESI) ion source. The method shows high linearity, specificity, accuracy and precision. The limits of detection are 40x to 55x lower than with UV-based methods.

Sensitive method for the detection of 22 benzodiazepines by gas chromatography–ion trap tandem mass spectrometry

A gas chromatography–ion trap tandem mass spectrometry method for simultaneous detection of 22 benzodiazepines is presented. Four operating modes were first optimized: the electron impact ionization and chemical ionization modes were compared on both underivatized and trimethylsilylated drugs. Results were compared in terms of sensitivity in MS–MS experiments. The trimethylsilylation of benzodiazepines including a protic functional group allows decreasing their detection threshold by a factor of 10–100. In terms of sensitivity, the comparison between both ionization modes shows that the most efficient one depends on the benzodiazepine considered. The use of an ion trap analyzer allows switching from an ionization mode to another one during the chromatographic process. It also provides a great selectivity owing to the MS–MS and multiple reaction monitoring acquisition modes. The detection thresholds are in the range 10–500 pg/μl for all the studied benzodiazepines but the three “triazolo” ones: estazolam, alprazolam and triazolam, have a detection threshold of 1 ng/μl. The applicability of the method on whole blood and urine extracts was demonstrated on an example implying five benzodiazepines among the most frequently encountered in forensic toxicology: nordazepam, oxazepam, bromazepam, flunitrazepam and prazepam.