Gas Chromatography-selected Ion Monitoring Research Articles

Multi-Residual Determination of Multi-Class Pesticides in Groundwater by Direct Immersion Solid-Phase Microextraction with Gas Chromatography-Selected Ion Monitoring Mass Spectrometry (GC–MS/SIM) Detection

Multi-Residual Determination of Multi-Class Pesticides in Groundwater by Direct Immersion Solid-Phase Microextraction with Gas Chromatography-Selected Ion Monitoring Mass Spectrometry (GC–MS/SIM) Detection

Development and Validation of a HS-SPME-GC-SIM-MS Multi-Method Targeting Hop-Derived Esters in Beer

Hop-derived esters contribute to beer flavor and changes in the ester spectrum are believed to be an important driver in the flavor–instability of hoppy beers. To date, there exists no published method that enables reliable quantification of hop-derived esters in beer. As the availability of such a method is vital to enlarge the understanding of beer flavor stability, the current article is concerned with the development, validation, and application of a headspace solid phase microextraction gas chromatography selected ion monitoring mass spectrometry (HS-SPME-GC-SIM-MS) based methodology for quantification of 16 hop-derived esters in beer. The validation data shows that choosing suitable HS-SPME-GC-SIM-MS conditions enabled reliable quantification of esters across a range of 1–200 µg/L, with calculated limits of quantification being well below 1 µg/L. Spiking experiments using terpenes and terpenoids evidenced method robustness, most importantly when two commercially available stable isotope labeled internal standards (d6-geranyl acetate and 13C-methyl octanoate) were used. Application to beer samples indicated that beers brewed with different qualities/quantities of hops and differing in freshness could be well differentiated by HS-SPME-GC-SIM-MS analysis of their ester profile. Supplemental data for this article is available online at at https://doi.org/10.1080/03610470.2021.1994814 .

A gas chromatography–mass spectrometry method for the detection of chlorpyrifos contamination in palm‐based fatty acids

AbstractChlorpyrifos is a Malaysian Pesticide Board‐approved organophosphate insecticide, which may become concentrated during fractionation. The objective of this project was to develop and validate a method to detect and quantify chlorpyrifos in food‐grade fatty acids ingredients, e.g. caprylic‐capric acid mixture and oleic acid (OLA) used to synthesize triacylglyceride based food additives and in the cosmetic industry. A selective ion monitoring gas chromatography–mass spectrometry method with a matrix‐matched calibration curve calibration was selected. The method involved the direct injection of chlorpyrifos spiked into the fatty acids matrix. The percentage recoveries at spiking levels of 0.5, 0.75, 2.5, and 4.0 μg g−1 of chlorpyrifos in OLA and caprylic‐capric acid ranged from 85.7%–101.1% to 97.2%–112%, respectively, with a relative standard deviation of within 11%. The intra‐day and inter‐day precision were deemed acceptable as indicated by an relative SD value of within 10%. A good linear relationship with a coefficient of correlation >0.99 for the matrix‐matched calibration was achieved between 0.5 and 5 μg g−1. The limit of detection and limit of quantification corresponded to 0.5 μg g−1 for OLA and 0.55 μg g−1 for caprylic‐capric acid.

Determination of 24 Pesticides Residues in Leather Products by Solid-Phase Microextraction Coupled with Gas Chromatography–Mass Spectrometry

Considering the high content of oil and complex residual additives in leather samples, a new analytical method based on the solid-phase extraction technique and gas chromatography-selected ion monitoring mass spectrometry (GC-SIM-MS) was developed to determine 24 organic compounds involving the organochlorine pesticides (OCPs), organophosphorous pesticides (OPPs) and pyrethroids pesticides residues in leather. The extraction conditions (such as the extraction solution, purification procedure and solid-phase extraction column) were optimized using the positive leather samples based on the recovery rates of the pesticides. The best extraction solution, solid-phase extraction column and chromatography column were n-hexane and ethyl acetate (1+1, volume) mixed solution, Carb-PSA (1.0 g, 6mL) and DB-1701 (length: 30 m, inside diameter: 0.25 mm, film thickness: 0.25 μm). The optimized extraction time and temperature were 20 min and 25°C, respectively. The detection limits of 24 pesticide residues range from 0.05 to 0.10 mg/kg, and the recoveries range from 74% to 116%. The relative standard deviations (RSD, n=6) range from 5.42% to 12.00%. The developed method presented a simple, rapid, sensitive, and inexpensive method to detect 24 pesticides in skin and leather and was successfully applied to the detect them in leather products (cowhide, sheep leather and pig leather).

A Selective Gas Chromatography-Selected Ion Monitoring Mass Spectrometry (GC‑MS/SIM) Method to Determine Polychlorinated Biphenyls in Fuller's Earth

Polychlorinated biphenyls (PCBs) are carcinogenic to humans and can be found in Fuller’s earth used for the regeneration of used transformer oil. This work describes a highly selective gas chromatographic-selected ion monitoring mass spectrometric method (GC-MS/SIM) for the simultaneous determination of three Aroclor PCB congener mixtures (1242, 1254, and 1260). The separation of the PCBs could be systematically varied by changing the temperature conditions of the chromatographic column. Methods were first selected from the literature, and the resolution of the PCBs was then optimized by adjusting k* (effective retention), a (selectivity), and N (column efficiency), enabling the detection of 83 PCBs in 35 min. The extract of PCBs from Fuller’s earth was obtained by ultrasonication (employing hexane and acetone as solvents) and cleanup with Florisil and was concentrated to about 500 µL. The ions analyzed in SIM mode were divided into groups according to the similarity (m/z) of the PCB fragmentation profiles. The limits of detection (LOD) and quantification (LOQ) were 0.19 and 0.64 µg kg-1, respectively. The method developed was used to determine the PCBs present in Fuller’s earth provided by an electric power company. The mean total PCBs concentration was found 1.9 µg kg-1 in Fuller’s earth.

Identification of potential indicators of time-dependent tequila maturation and their determination by selected ion monitoring gas chromatography–mass spectrometry, using salting-out liquid–liquid extraction

In this work, gas chromatography–mass spectrometry (GC–MS) profiles obtained for a series of rested and aged tequilas were statistically compared to identify volatile compounds indicative of time-dependent tequila maturation. For the determination of nine selected compounds, 2-acetylthiazole was added as internal standard, ethyl acetate extraction was carried out in the presence of sodium chloride (salting-out) and sodium sulfate was used to eliminate water traces. Baseline separation was achieved within 18 min and quantification was carried out by selected ion monitoring. The method detection limits were as follows: 2.10 µg L− 1 guaiacol (m/z 109), 1.78 µg L− 1 4-methylguaiacol (m/z 123), 1.97 µg L− 1 4-ethylguaiacol (m/z 137), 3.78 µg L− 1trans-whiskey lactone (m/z 99), 4.42 µg L− 1cis-whiskey lactone (m/z 99), 10.3 µg L− 1eugenol (m/z 103), 8.27 µg L− 1 vanillin (m/z 151), 14.2 µg L− 1 apocynin (m/z 151), 12.1 µg L− 1 syringaldehyde (m/z 182). For accuracy testing, 100 µg L− 1 of each analyte was added to silver tequila, yielding the recoveries in the range 92.1–116%. Data obtained in the analysis of 28 tequilas confirmed that the concentrations of individual compounds were changing among liquors at different maturation stage; however, due to many variables affecting the profile of volatile/semi-volatile compounds during aging in wooden barrels, discrimination of tequilas was not feasible. Otherwise, the proposed procedure allows for reliable determination of nine odor-active compounds in tequila at trace levels with simple sample pretreatment and short analytical run.

Exploring metabolic syndrome serum free fatty acid profiles based on GC–SIM–MS combined with random forests and canonical correlation analysis

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities associated with an increased risk of developing cardiovascular diseases or type II diabetes. Till now, the etiology of MetS is complex and still unknown. Metabolic profiling is a powerful tool for exploring metabolic perturbations and potential biomarkers, thus may shed light on the pathophysiological mechanism of diseases. In this study, fatty acid profiling was employed to exploit the metabolic disturbances and discover potential biomarkers of MetS. Fatty acid profiles of serum samples from metabolic syndrome patients and healthy controls were first analyzed by gas chromatography–selected ion monitoring–mass spectrometry (GC–SIM–MS), a robust method for quantitation of fatty acids. Then, the supervised multivariate statistical method of random forests (RF) was used to establish a classification and prediction model for MetS, which could assist the diagnosis of MetS. Furthermore, canonical correlation analysis (CCA) was employed to investigate the relationships between free fatty acids (FFAs) and clinical parameters. As a result, several FFAs, including C16:1n-9c, C20:1n-9c and C22:4n-6c, were identified as potential biomarkers of MetS. The results also indicated that high density lipoprotein-cholesterol (HDL-C), triglycerides (TG) and fasting blood glucose (FBG) were the most important parameters which were closely correlated with FFAs disturbances of MetS, thus they should be paid more attention in clinical practice for monitoring FFAs disturbances of MetS than waist circumference (WC) and systolic blood pressure/diastolic blood pressure (SBP/DBP). The results have demonstrated that metabolic profiling by GC–SIM–MS combined with RF and CCA may be a useful tool for discovering the perturbations of serum FFAs and possible biomarkers for MetS.

Authentication of pineapple (Ananas comosus [L.] Merr.) fruit maturity stages by quantitative analysis of γ- and δ-lactones using headspace solid-phase microextraction and chirospecific gas chromatography–selected ion monitoring mass spectrometry (HS-SPME–GC–SIM-MS)

Headspace solid phase microextraction and chirospecific gas chromatography–mass spectrometry in selected ion monitoring mode (HS-SPME–GC–SIM-MS) allowed quantitative determination of δ-lactones (δ-C8, δ-C10) and γ-lactones (γ-C6, γ-C8, γ-C10). A stable isotope dilution assay (SIDA) with d7-γ-decalactone as internal standard was used for quantitative analysis of pineapple lactones that was performed at three progressing post-harvest stages of fully ripe air-freighted and green-ripe sea-freighted fruits, covering the relevant shelf-life of the fruits. Fresh pineapples harvested at full maturity were characterised by γ-C6 of high enantiomeric purity remaining stable during the whole post-harvest period. In contrast, the enantiomeric purity of γ-C6 significantly decreased during post-harvest storage of sea-freighted pineapples. The biogenetical background and the potential of chirospecific analysis of lactones for authentication and quality evaluation of fresh pineapple fruits are discussed.

Determination of Polycyclic Aromatic Hydrocarbons in Coffee and Coffee Substitutes using Dispersive SPE and Gas Chromatography-Mass Spectrometry

The purpose of this study was to evaluate the application of dispersive solid-phase extraction with the use of primary secondary amine (PSA), NH2 and strong anion exchange (SAX) sorbents for polycyclic aromatic hydrocarbon (PAH) determination in samples of coffee. The final extracts were analysed by gas chromatography selected ion monitoring mass spectroscopy (GC-SIM-MS). The results indicated that cleanup with PSA and SAX sorbents followed by final solvent exchange from acetonitrile to hexane (liquid–liquid extraction, LLE) was the best variant of the method, resulting in the cleanest extracts and satisfactory compound recoveries (70–104 %) for examined compounds in coffee samples. In the study of real samples, the concentrations of PAH markers (benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene) were higher for natural roasted coffee (7.20–68.15 μg kg−1), than for instant coffee (2.97–19.55 μg kg−1) and cereal coffee (8.15–15.35 μg kg−1), and the sum of PAHs was also higher in natural and instant coffees compared to coffee substitutes (364, 343 and 265 μg kg−1, respectively). However, in all samples of coffee, light (three-ring) PAHs dominated within the identified compounds and phenanthrene was the most abundant compound, approaching 209.67 μg kg−1 in roasted coffee.

Cork as a new (green) coating for solid-phase microextraction: Determination of polycyclic aromatic hydrocarbons in water samples by gas chromatography–mass spectrometry

A new fiber for solid-phase microextraction (SPME) was prepared employing cork as a coating. The morphology and composition of the cork fiber was evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The proposed fiber was used for the determination of polycyclic aromatic hydrocarbons (PAHs) in river water samples by gas chromatography–selected ion monitoring–mass spectrometry (GC–SIM–MS). A central composite design was used for optimization of the variables involved in the extraction of PAHs from water samples. The optimal extraction conditions were extraction time and temperature of 60min and 80°C, respectively. The detection and quantification limits were 0.03 and 0.1μgL−1, respectively. The recovery values were between 70.2 and 103.2% and the RSD was ≤15.7 (n=3). The linear range was 0.1–10μgL−1 with r≥0.96 and the fiber-to-fiber reproducibility showed RSD≤18.6% (n=5). The efficiency of the cork fiber was compared with commercially available fibers and good results were achieved, demonstrating the applicability and great potential of cork as a coating for SPME.

Membrane bioreactor treatment of commonly used organophosphate pesticides

Five pesticide formulations registered for use in Canada containing organophosphate-insecticide active ingredients azinphos-methyl, chlorpyrifos, diazinon, malathion and phorate were subjected to treatment by membrane bioreactor (MBR) technology. The target active ingredients were introduced to the MBR at ppm level concentrations. The biodegradation of these compounds was analyzed daily using selected ion monitoring gas chromatography−mass spectrometry (GC/MS-SIM) following extraction of the analytes using solid-phase extraction (SPE). Amounts measuring 83 % to 98 % of the target analytes were removed with steady-state concentrations being reached within 5 days of their introduction. The dissolved oxygen, temperature, pH, and total heterotrophic bacterial population were monitored daily to ensure optimal conditions for biodegradation. The quality of the effluent from the MBR was assessed daily through spectrophotometric methods. Measurements were conducted for the concentration of ammonia, nitrate, nitrite, total and reactive phosphorus, as well as the chemical oxygen demand (COD) of the effluent. This study demonstrated that the MBR technology is feasible and efficient for treatment of organophosphate pesticides without introducing additional chemical additives.

A GC-SIM-MS Method for the Determination of Butylidenephthalide in Rat Plasma and Tissue: Application to the Pharmacokinetic and Tissue Distribution Study

Butylidenephthalide is one of the major active components isolated from Rhizoma Chuanxiong. This paper describes a simple, rapid, specific and sensitive method for the quantification of butylidenephthalide in rat plasma and tissue distribution using a liquid-liquid extraction procedure followed by capillary gas chromatography-selected ion monitoring mode-mass spectrometry (GC-SIM-MS) analysis. The calibration curves were linear over the concentration ranging from 0.02–10.0 µg/mL (r > 0.99) for plasma samples and 0.18–7.25 µg/g (r > 0.99) for the tissue samples. The limit of quantification (LOQ) was 1.0 ng/mL or 1.0 ng/g (ten times signal/noise ratio). Within- and between-day precisions expressed as the relative standard deviation (RSD) for the method were 2.39–2.98% and 2.97–4.26%, respectively. The methods of recovery for all samples were greater than 80% at the low, medium, and high concentrations. The method has been successfully applied to a pharmacokinetics study in rats after an oral administration of Butylidenephthalide with a dose of 20.0 mg/kg. The main pharmacokinetic parameters obtained were T max = (0.22 ± 0.06) h, C max = (3 ± 1) µg/mL, AUC = (32 ± 6) h•µg/mL, and K a = (8.5 ± 0.8)/h. The results showed that the butylidenephthalide was easily absorbed. The concentrations of butylidenephthalide in rat kidney, lung, heart, and cerebellum were higher than those in other organs. To determine free fraction in serum, samples were filtered using ultrafiltration membranes with a molecular weight cut-off of 10,000 Da and extracted using liquid-liquid extraction. The extracts were evaporated and analyzed by GC-MS. The protein binding in rat plasma, human plasma, and human serum albumin were 83 ± 4%, 94 ± 3%, and 89 ± 3%, respectively.

A capillary gas chromatography-selected ion monitoring mass spectrometry method for the analysis of atractylenolide I in rat plasma and tissues, and application in a pharmacokinetic study

The aim of this paper is to investigate the characteristics of atractylenolide I (AO-I) in the body by a GC–MS method. All bio-samples were cleared up with a liquid–liquid extraction procedure. The calibration curves were linear within a range of 5–1000 ng/mL for plasma samples, 0.06–16.00 μg/g for cerebellum samples, and 0.03–8.00 μg/g for other tissue samples. The limit of quantification (LOQ) for AO-I was 1.0 ng/mL or 1.0 ng/g (S/N ≥ 10) in the bio-samples. In the applications, the main pharmacokinetic parameters were firstly obtained as follows: T max = 0.37 ± 0.19 h, C max = 0.26 ± 0.05 μg/mL, AUC = 1.95 ± 0.30 μg h/mL and k a = 10.08 ± 5.60 h −1. The tissue distribution of AO-I in rats after the oral administration of 50.0 mg/kg was from 0.225 to 0.031 μg/g with a decreasing tendency in different tissues like liver > kidney > spleen > cerebellum > heart > cerebrum > lung. The protein binding in rat plasma, human plasma and bovine serum albumin was 80.8 ± 3.9, 90.6 ± 3.1 and 60.9 ± 5.1%, respectively.

3-Chlorotyrosine and 3,5-Dichlorotyrosine as Biomarkers of Respiratory Tract Exposure to Chlorine Gas*

Modification of tyrosine by reactive chlorine can produce both 3-chlorotyrosine (CY) and 3,5-dichlorotyrosine (dCY). Both of these amino acids have proven to be promising biomarkers for assessing the extent of myeloperoxidase-catalyzed chlorine stress in a number of adverse physiological conditions. To date, there has been no application of these biomarkers for determining the extent of exposure to environmentally present gaseous chlorinating chemicals. In this manuscript, we present a method using selective ion monitoring gas chromatography for the simultaneous analysis of both CY and dCY in nasal tissue excised from Fisher 344 rats exposed to varying concentrations of chlorine gas. Using this method, we were able to demonstrate the following: 1. a dose-dependent increase in the conversion of tyrosine to CY and dCY in the respiratory epithelium tissue; 2. preferential formation of CY and dCY in the respiratory and transitional epithelium versus the olfactory epithelium of the nasal cavity of the rat; and 3. similar rates of formation for CY and dCY when exposed to chlorine gas based on a strong [CY] versus [dCY] correlation (slope = 1.001, r(2) = 0.912).

2-Aminoadipic acid is a marker of protein carbonyl oxidation in the aging human skin: effects of diabetes, renal failure and sepsis

We hypothesized that the epsilon-amino group of lysine residues in longlived proteins oxidatively deaminates with age forming the carbonyl compound, allysine (alpha-aminoadipic acid-delta-semialdehyde), which can further oxidize into 2-aminoadipic acid. In the present study, we measured both products in insoluble human skin collagen from n=117 individuals of age range 10-90 years, of which n=61 and n=56 were non-diabetic and diabetic respectively, and a total of n=61 individuals had either acute or chronic renal failure. Allysine was reduced by borohydride into 6-hydroxynorleucine and both products were measured in acid hydrolysates by selective ion monitoring gas chromatography (GC)-MS. The results showed that 2-aminoadipic acid (P<0.0001), but not 6-hydroxynorleucine (P=0.14), significantly increased with age reaching levels of 1 and 0.3 mmol/mol lysine at late age respectively. Diabetes in the absence of renal failure significantly (P<0.0001) increased 2-aminoadipic acid up to <3 mmol/mol, but not 6-hydroxynorleucine (levels<0.4 mmol/mol, P=0.18). Renal failure even in the absence of diabetes markedly increased levels reaching up to <0.5 and 8 mmol/mol for 6-hydroxynorleucine and 2-aminoadipic acid respectively. Septicaemia significantly (P<0.0001) elevated 2-aminoadipic acid in non-diabetic, but not diabetic individuals, and mildly correlated with other glycoxidation markers, carboxymethyl-lysine and the methylglyoxal-derived products, carboxyethyl-lysine, argpyrimidine and MODIC (methylglyoxal-derived imidazolium cross-link). These results provide support for the presence of metal-catalysed oxidation (the Suyama pathway) in diabetes and the possible activation of myeloperoxidase during sepsis. We conclude that 2-aminoadipic acid is a more reliable marker for protein oxidation than its precursor, allysine. Its mechanism of formation in each of these conditions needs to be elucidated.

Brassinosteroid deficiency due to truncated steroid 5alpha-reductase causes dwarfism in the lk mutant of pea.

The endogenous brassinosteroids in the dwarf mutant lk of pea (Pisum sativum) were quantified by gas chromatography-selected ion monitoring. The levels of castasterone, 6-deoxocastasterone, and 6-deoxotyphasterol in lk shoots were reduced 4-, 70-, and 6-fold, respectively, compared with those of the wild type. The fact that the application of brassinolide restored the growth of the mutant indicated that the dwarf mutant lk is brassinosteroid deficient. Gas chromatography-selected ion monitoring analysis of the endogenous sterols in lk shoots revealed that the levels of campestanol and sitostanol were reduced 160- and 10-fold, respectively, compared with those of wild-type plants. These data, along with metabolic studies, showed that the lk mutant has a defect in the conversion of campest-4-en-3-one to 5alpha-campestan-3-one, which is a key hydrogenation step in the synthesis of campestanol from campesterol. This defect is the same as that found in the Arabidopsis det2 mutant and the Ipomoea nil kbt mutant. The pea gene homologous to the DET2 gene, PsDET2, was cloned, and it was found that the lk mutation would result in a putative truncated PsDET2 protein. Thus it was concluded that the short stature of the lk mutant is due to a defect in the steroidal 5alpha-reductase gene. This defect was also observed in the callus induced from the lk mutant. Biosynthetic pathways involved in the conversion of campesterol to campestanol are discussed in detail.

Effects of long-term administrations of aconitine on electrocardiogram and tissue concentrations of aconitine and its metabolites in mice

Aconitum alkaloids are well known for their acute and high toxicity, for example, in the causation of severe arrhythmias leading to death. Aconitine, one of the major Aconitum alkaloids, is a highly toxic compound from the Aconitum species. However, there has been no studies reported on the influence of the chronic administration of aconitine. Thus, this study was conducted to investigate the influence of chronic administration of aconitine in experimental animal models. A dose of 1 mg/kg per day was administered to the experimental animal models. We determined the concentration of aconitine and its metabolites (benzoylaconine and aconine) in organs and blood with gas chromatography/selected ion monitoring (GC/SIM). In addition, we concurrently recorded the electrocardiogram (ECG). Fifteen minutes after administration on day 0, the early aconitine administered group (acute group) revealed peak organ and blood concentration levels of aconitine with a gradual decrease, thereafter. The concentration of aconitine in organs and blood (from days 0 to 22; 90 min after the last administration of aconitine) gradually decreased according to repeated administration, whereas benzoylaconine and aconine increased. ECG revealed various types of arrhythmias. However, the frequency of arrhythmias remarkably decreased with time and repeated administration of aconitine. These results indicate two possibilities. First, the increase in the activity of aconitine metabolism. Secondly, the decrease of effectiveness to the heart due to long-term (chronic) administration of aconitine.

Validated semiquantitative/quantitative screening of 51 drugs in whole blood as silylated derivatives by gas chromatography-selected ion monitoring mass spectrometry and gas chromatography electron capture detection

A comprehensively validated procedure is presented for simultaneous semiquantitative/quantitative screening of 51 drugs of abuse or drugs potentially hazardous for traffic safety in serum, plasma or whole blood. Benzodiazepines (12), cannabinoids (3), opioids (8), cocaine, antidepressants (13), antipsychotics (5) and antiepileptics (2) as well as zolpidem, zaleplon, zopiclone, meprobamate, carisoprodol, tizanidine and orphenadrine and internal standard flurazepam, were isolated by high-yield liquid-liquid extraction (LLE). The dried extracts were derivatized by two-step silylation and analyzed by the combination of two different gas chromatographic (GC) separations with both electron capture detection (ECD) and mass spectrometry (MS) operating in a selected ion-monitoring (SIM) mode. Quantitative or semiquantitative results were obtained for each substance based on four-point calibration. In the validation tests, accuracy, reproducibility, linearity, limit of detection (LOD) and limit of quantitation (LOQ), selectivity, as well as extraction efficiency and stability of standard stock solutions were tested, and derivatization was optimized in detail. Intra- and inter-day precisions were within 2.5–21.8 and 6.0–22.5%, and square of correlation coefficients of linearity ranged from 0.9896 to 0.9999. The limit of quantitation (LOQ) varied from 2 to 2000 ng/ml due to a variety of the relevant concentrations of the analyzed substances in blood. The method is feasible for highly sensitive, reliable and possibly routinely performed clinical and forensic toxicological analyses.

Chemometric approach for the resolution and quantification of unresolved peaks in gas chromatography–selected-ion mass spectrometry data

A semiautomated and integrated chemometric approach is presented for the resolution and quantification of unresolved target-analyte signals in gas chromatography-selected-ion monitoring (GC-SIM) data collected using scanning mass spectrometers. The chemometric approach utilizes an unskewing algorithm and two multivariate chemometric methods known as rank alignment and the generalized rank annihilation method (GRAM). The unskewing algorithm corrects the retention-time differences within a single GC-SIM data matrix caused by using a scanning mass spectrometer. Rank alignment objectively corrects the run-to-run retention-time difference between a sample GC-SIM data matrix and a standard addition GC-SIM data matrix. GRAM analysis uses the sample and standard addition data matrices to mathematically resolve and quantify the target-analyte signal(s). The resolution and quantification of severely unresolved target-analyte signals are demonstrated using GC-SIM data obtained from conventional heart-cut two-dimensional gas chromatography with mass spectrometric detection. In addition, the GC-SIM data is used to demonstrate the result of chemometric analysis when the absence of a target-analyte signal is obscured by interference. Chemometric analysis is shown to unambiguously detect an analyte based on its resolved mass chromatograms in situations where the traditional approach of measuring peak height fails to positively detect it. The predicted analyte concentrations are within 8% of the reference concentrations.

Two Survival Cases Of Severe Aconite Poisoning By Percutaneous Cardiopulmonary Support System And Cardiopulmonary Bypass For Fatal Arrhythmia: A Case Report

Objective: to propose adequate treatment of fatal aconite poisoning using percutaneous cardiopulmonary support system and cardiopulmonary bypass. Design: case study. Setting: cardiac care unit in a university hospital. Patient: a 17-yr-old man ingested aconite roots to commit suicide and a 41-yr-old man eaten aconite tubers by accident. Intervention: immediate application of percutaneous cardiopulmonary support system and cardiopulmonary bypass for fatal arrhythmia caused by aconite. Measurements and main results: continuous ecg monitoring was performed. Concentrations of aconites in blood were measured by gas chromatography selected ion monitoring during institution of percutaneous cardiopulmonary support system and cardiopulmonary bypass. The changes of aconite concentration in blood showed that these concentrations are decreased under critical level 24 hours later from ingestion. At the same time fatal arrhythmias were also disappeared. The patients improved fatal arrhythmia and systemic circulation and discharged without neurological deficit. Conclusion: immediate application of percutaneous cardiopulmonary support system and cardiopulmonary bypass enable to survive fatal aconite poisoning patients.