Gas Chromatography-mass Spectrometry Test Research Articles

The gas production characteristics and catastrophic hazards evaluation of thermal runaway for LiNi0.5Co0.2Mn0.3O2 lithium-ion batteries under different SOCs

Lithium-ion batteries (LIBs) are widely used as electrochemical energy storage systems in electric vehicles due to their high energy density and long cycle life. However, fire accidents present a trend of frequent occurrence caused by thermal runaway (TR) of LIBs, so it is especially important to evaluate the catastrophic hazards of these LIBs. This study conducted the adiabatic TR test coupled gas production test, Gas Chromatography-Mass Spectrometry test, and explosion limit test on a commercial LIB with Ni0.5Co0.2Mn0.3 as the cathode material at different states of charge (SOCs). The results show that the TR temperature and the maximum temperature at low SOC are lower compared to that at a high SOC. The probability of LIBs TR at less than SOC = 50 % is small and also causing less harm. For the gas production characteristics, the lower the SOC of the battery, the lower the gas production volume. The peak and steady-state gas production increase with the increase of SOC. For the mixed gases generated during TR, the content of CO2 shows a trend of decreasing with the increasing of battery SOC, while that of H2 and CO increase with the increasing of SOC. For the explosion limit of the mixed gas, the lower explosion limit and upper explosion limit decrease and increase with the increasing of SOC, respectively. Finally, based on the seven parameters related to the TR gas production of LIBs and so on, the analytic hierarchy process method was used to establish a LIB TR disaster-causing hazard evaluation system. The evaluation system can quantitatively evaluate the thermal safety of a LIB. This is instructive for establishing a comprehensive quantitative evaluation method for battery safety in practical engineering applications.

Phytochemical Screening and GC-MS Analysis of Methanolic and Aqueous Extracts of Ocimum kilimandscharicum Leaves.

Kenyans have long utilized Ocimum kilimandscharicum, an East African permanent evergreen plant, to treat measles, stomachaches, diarrhea, mosquito bites (anti-insect), congested chest, cough, and colds. Using conventional qualitative and quantitative techniques, this study was done to identify the secondary metabolites in O. kilimandscharicum leaf extracts. The chemical content of the crude extracts from the leaves of O. kilimandscharicum has also been investigated and characterized using gas chromatography-mass spectrometry (GC-MS). By using a 1:20 dilution in methanol, in cold maceration, a fine powder of O. kilimandscharicum was first extracted then filtered and concentrated after 72 h utilizing a rotary evaporator. By using also a 1:20 dilution in water at 80 °C, a fine powder of O. kilimandscharicum was extracted and then filtrated and lyophilized 1 h later. Each extract underwent further gas chromatography-mass spectrometry testing. We found that both extracts contain secondary metabolites such as alkaloids, phenolics, flavonoids, saponins, and tannins. However, the overall amount of phytochemicals in each solvent varied significantly. Total phenolics contents (TPCs) were 5.6 ± 1.20 and 10.8 ± 1.00 mg, total flavonoid contents (TFCs) were 8.2 ± 0.4 and 39.6 ± 2.2 mg, total tannin contents (TTCs) were 0 ± 0.00 and 10.5 ± 0.4 mg, the total alkaloid content (TAC) was 49.2 ± 0.40%, and the total saponin content (TSC) was 38 ± 2.00%. Additionally the gas chromatography-mass spectrometry, revealed a number of high- and low-molecular-weight bioactive molecules at various concentrations for each extract. We also found an inhibitory effect on adhP and chbR gene expression of Staphylococcus aureus and Salmonella choleraesuius, respectively. Hence, these chemicals could potentially have a biological and pharmacological significance. Therefore, the discovery of many physiologically active chemicals in the leaf extracts of O. kilimandscharicum justifies future biological and pharmaceutical research.

Characterization of the key odorant compounds in ‘Qinguan’ apples (Malus × domestica)

‘Qinguan’ apple is native to China with the outstanding qualities of disease resistance and long storage time. In this study, gas chromatography-mass spectrometry (GC-MS) was used to identify the volatile compounds in peel and flesh of post-harvest ‘Qinguan’ apples. Ninety-four and seventy volatile compounds were identified in ‘Qinguan’ peel and flesh, respectively. Esters and alcohols were predominant in ‘Qinguan’ peel, while alcohols were identified as the main volatiles in ‘Qinguan’ flesh. Odor-active compounds and the sensory profile of ‘Qinguan’ apples were investigated by aroma extract dilution analysis-gas chromatography-olfactometry (AEDA-GC-O) and sensory description analyses. The sensory profile of ‘Qinguan’ apples was mainly characterized by aroma descriptors of fruity and green categories. Among the 15 odor-active compounds with flavor dilution factor (FD) ranging from 3 to 81, hexyl acetate, α-farnesene, hexanol, and hexanal (with FD = 81) were shown to be the most potent odor-active compounds in ‘Qinguan’ apples. Based on the results obtained from GC-MS, AEDA-GC-O, and omission tests, hexyl acetate as the most abundant ester in peel was suggested to be one of the characteristic aroma compounds of ‘Qinguan’ apple, contributing to its strong fruity aroma note, while the other characteristic aroma compound, α-farnesene, was responsible for the green note.

Influence of smoke suppressant on the smoke inhibition effect and properties of different types of asphalt

The current understanding of the influence of smoke suppressants on the smoke inhibition effect and working performance of different types of asphalt is limited. In this study, portable gas detector (PGD) tests were used to investigate the influence of the smoke suppressant on different types of asphalt and the smoke purification effect. Subsequently, gas chromatography-mass spectrometry (GC-MS) was used to analyze the influence of the smoke suppressant on the volatile organic compounds (VOCs) in different types of asphalt fume, so as to compare and verify the PGD tests results. Finally, scanning electron microscopy and energy dispersive spectrometry were used to observe and analyze the influence of the smoke suppressant on the microstructure and element composition of different types of asphalt. The results show that the smoke suppressant can purify various harmful gases volatilized from different types of asphalt, but the effect and the optimal dosage of smoke suppressant are slightly different. The purification rate of the smoke suppressant for SO2 or H2S in the fumes of various asphalts can reach >70% and the NO and VOC purification rates can reach >40%. The influence of the smoke suppressant on the VOC purification rate of different asphalts detected through the GC-MS and PGD tests is similar. The smoke suppressant has little effect on the asphalt surface microstructure and on the changes in the element content in asphalt, indicating that it has no effect on the main properties of the asphalt itself. This study is helpful to further understand the relationship between smoke suppressants and the smoke inhibition effect and the working performance of different types of asphalt. Additionally, it provides basis and guidance for the development of low-smoke asphalt with a better emission reduction effect, which has a certain guiding and application significance.

Anti-Mitoticpotential Identification of Nyale (Eunice sp.) in The Tourism Area of Kuta Beach, Lombok Island, West Nusa Tenggara

BACKGROUND: BauNyale festival is a Lombok tradition that originated in the Kuta beach tourism area in Central Lombok. The locals of Lombok Island gathered in this location to harvest marine worms known as Nyale (Eunice sp.). The ability of marine worms to act as anticancer agents has received little attention in Indonesia. AIM: This study aimed to examine the biomolecules compounds of Nyale as antimitotic candidates. METHODS: This was a preliminary study using post-test only with a control group design. The sample of this study was Nyale (Eunice sp.), and sea urchin (Tripneustes ventricosus) collected from Kuta beach, Central Lombok. The Nyale was extracted with 96% ethanol as the solvent. Gas Chromatography-Mass Spectrometry (GCMS) was used to determine the content of bioactive compounds. Sea urchin embryos were divided into four treatment groups (control; 10 mg, 100 mg, and 1000 mg; 1000 mg of Nyale extract). After 2 h of fertilization incubation, the number of cell division phases (2–32 cells) was counted. The data were analyzed using ANOVA. RESULTS: The results of the GCMS test revealed that there were ten different compounds in the Nyale ethanol extract. There was a tendency for cleavage when testing the anti-mitotic potential of Nyale extract in each group. There was a significant difference in the percentage of cell changes in all treatments (control, 10 mg, 100 mg, and 1000 mg) (p < 0.005). CONCLUSION: Bioactive compounds found in marine worms (nyale) influence the percentage of cell division (anti-mitotic) in sea urchin embryos.

Buprenorphine not detected on urine drug screening in supervised treatment.

Urine drug screens (UDS) assist in clinical planning and assessment of adherence in opioid agonist treatment (OAT). Urine drug screens may also be used in criminal justice and child protection settings. Buprenorphine (BPN) UDS testing is complex. Immunoassay often does not detect BPN and gas chromatography-mass spectrometry (GC-MS) is needed. A limited understanding of testing can negatively influence UDS interpretation and clinical decision making. The primary aim was to determine detection rates of BPN in UDS in participants on BPN or buprenorphine/naloxone (BNX) treatment. The secondary aim was to identify if comorbidities, sex, co-prescribed medications, or dosing site and observation were associated with BPN detection. Public outpatient clinic in a specialist addiction treatment service. In this retrospective observational study, records of clients on supervised BPN/BNX treatment between September 2017 and 2018 were reviewed. Data extracted included UDS results, age, sex, indication for BPN, frequency of observed doses, dose of BPN, dosing site, comorbid medical conditions, and medications. One hundred and sixty-one medical records were reviewed. Ninety-seven (60 percent) underwent screening urine immunoassay. Of these 97, 51 (53 percent) had further GC-MS testing for BPN of which 22 (43 percent) did not detect BPN despite directly observed OAT. Co-prescription of medications known to interact with cytochrome P450 3A4 was associated with nondetection of BPN (p < 0.05). No significant association between median dose, dosing site, and observed dosing and BPN detection was identified. Urine drug testing for BPN is complex. Failure to detect BPN does not betoken nonadherence to treatment and is associated with co-prescription of drugs interacting with cytochrome P450 3A4.

Isolasi Senyawa Anti Bakteri Geraniol Dari Minyak Sereh Wangi (Citronella Oil) Dengan Menggunakan Distilasi Vakum

This study aims to increase geraniol levels in citronella oil, using vacuum distillation. Geraniol is a compound that has been legalized by IFRA (Fragrance International Association) as a scent compound, so geraniol is a reference to be formulated in the form of Anti-bacterial perfume products, but the levels of geraniol in citronella oil are still very low. This encourages the processing of fragrant citronella oil to be processed, by increasing geraniol levels using vacuum distillation, with variations in pressure: 8,6,4,2,1 mbar, during operating times: 20, 40, and 60 minutes up to FBP ( Final Boiling Point). Samples were analyzed using GC-MS (Gas Chromatography-Mass Spectrometry), FT-IR, refractive index, and bacterial testing. The results showed that the use of low pressure affected increasing geraniol levels. The maximum increase in geraniol content was 80.11% at a pressure of 1 mbar at the Final Boiling Point operation, with a refractive index of 1.501, whereas in the FTIR test there was an intense broad peak in the range 2200-3200 cm-1 especially at 3086.98cm-1 according to the OH hydroxyl polymer group at Geraniol. This study increased geraniol levels from 20.32% to 80.11%.

Simultaneous determination of four opioids in urine by solid-phase extraction and derivatization coupled with gas chromatography-mass spectrometry

Police officers currently use the colloidal gold rapid testing method to detect heroin in the urine of drug abusers, but the results are often rendered erroneous due to the presence of antitussive drugs, which contain opioids. The traditional manual liquid-liquid extraction method for urine testing has low efficiency and poor sensitivity, and hence, it fails to meet the requirements of the public security department to crack down on drug abusers. Therefore, to avoid punishment, most rapid-test-positive people make false claims about intaking cough suppressants. It is imperative to establish a highly efficient automatic method for the simultaneous determination of multiple opioids in urine, to rule out the use of heroin. A method based on solid-phase extraction and derivatization coupled with gas chromatography-mass spectrometry (GC-MS) has been developed for the simultaneous detection of morphine, O6-acetylmorphine, codeine, and acetyl codeine in urine. Since these four opioids exists as cations in acidic aqueous solution, the urine samples collected from dead bodies or drug addicts were adjusted to pH 6 by using phosphate buffer, enriched, and purified by MCX-SPE columns. Then, morphine, O6-acetylmorphine, and codeine were derivatized by N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) for GC-MS testing. The effects of sample loading and elution flow rate, percentage of formic acid in the wash solvent (methanol), percentage of ammonia in the eluent (methanol), volume of the wash solvent, and drying time of the cartridge on the extraction efficiency were investigated in detail. The best results were obtained under the following conditions:sample loading and elution flow rate, 1.0 mL/min; volume fraction of formic acid in the wash solvent, 3%; volume fraction of ammonia in the eluent solvent, 5%; volume of 3% (v/v) formic acid in methanol (eluent), 1 mL; and drying time of the cartridge, 1 min. The GC-MS results showed good linearity in the range of 0.02-0.8 μg/mL with correlation coefficients (r2) ≥ 0.998. The limits of detection (LODs) and limits of quantification (LOQs) were 0.0016-0.0039 μg/mL and 0.0054-0.0128 μg/mL, respectively. The recoveries of the target analytes were between 93.0% and 110.3% at spiked levels of 0.02, 0.1, and 0.2 μg/mL. As opposed to similar reported methods, our method showed high sensitivity and recovery; furthermore, the matrix interference was eliminated, and the chromatographic peaks of the analytes were completely separated from the impurity peaks at the level of 0.2 μg/mL. The automatic solid-phase extraction equipment is convenient to operate and allows one to process samples in batches. The conditions for solid-phase extraction can be precisely controlled, and the detection accuracy is greatly improved. In addition, a large number of sample tests can be performed by a few experimenters. Hence, this method facilitates simple and rapid forensic toxicology testing and drug abuse monitoring on a large scale.

Synthesis and Utilization of Mesoporous Hollow Silica Particles for Bitumen

Abstract In recent years, nanoparticles with special structures have been widely used in the traditional building material bitumen. For that, mesoporous hollow silica (MHS) particles were synthesized in this work. Scanning electron microscope, transmission electron microscope, and Brunauer-Emmett-Teller tests were conducted to characterize the specific structure. Then, MHS was used to improve the properties of the traditional construction binder material bitumen. Penetration, softening point, and dynamic shear rheometer tests were performed to study the physical and rheological properties of MHS-modified bitumen. A pyrolysis gas chromatography mass spectrometry test was used to evaluate the inhibition effect of MHS on the emission of the bitumen volatile organic compounds (VOCs). The results showed that MHS with continuous distributed pore diameters were simply synthesized in one step by hydrothermal method. MHS as a kind of additive could improve the high temperature rutting resistance of bitumen. In addition, because of the higher specific surface area and massive micropores, MHS had a significant inhibition effect on the emission of bitumen VOCs.

Experimental investigation to identify the type of waste plastic pyrolysis oil suitable for conversion to diesel engine fuel

Plastics for various applications is increasing every year due to outstanding advantages, but after use recycling and disposal have remained a challenge. In this paper, through experiments, we compare properties of pyrolysis oil derived from after use HDPE (High-density polyethylene), LDPE (Low-density polyethylene), PP (Polypropylene)and styrene for their suitability as diesel engine fuel. This experimental study is to identify which type of plastic is suitable for blending with diesel. The physicochemical properties of pyrolysis oil of HDPE, LDPE, PP, and styrene were tested, tabulated and compared with diesel. The physicochemical properties of polypropylene pyrolysis oil (PPO) were found to be superior to the produced pyrolysis oil of HDPE, LDPE, and styrene. The GC-MS(Gas chromatography-mass spectrometry)and FT-IR (Fourier transform-infrared spectroscopy) were taken for pyrolysis oil of HDPE, LDPE, PP, and styrene and compared with diesel. PPO showed lower carbon number chain compounds compared to the other three waste plastics. We selected PPO for diesel engine performance and emission trials based on the results of the above tests. PPO was blended in the ratios of 5%, 10% and 15% with diesel. Combustion analysis showed a increase in cylinder pressure in comparison to diesel values. The heat release rates (HRR) were sharply higher than diesel. Both cylinder pressure and HRRvalues for PPO increased as the blend ratios increased. The emission results showed an increase in carbon monoxide (CO), hydrocarbon (HC)and oxides of Nitrogen (NO x )emissions. The multiple times increase in emissions is due to the presence of unsaturated hydrocarbons and higher carbon number of saturated compounds in PPO. GC-MS tests confirmed the presence of such compounds in PPO. To reduce the unsaturation to negligible levels, we will take up future experiments in hydrogenating PPO with various catalysts and test the performance and emissions in diesel engines. The experiment and analysis plan for conversion of solid waste plastics to diesel fuel. • Four types of plastics selected to determine which plastic has a diesel like quality. • Physicochemical properties, FTIR, GCMS results showed Polypropylene had diesel like qualities. • Diesel Engine trials done with polypropylene pyrolysis oil blended with diesel as fuel. • Engine trial results showed delayed combustion, high heat release rate and higher emission.

In Vitro Antimicrobial Activity and GC-MS Analysis of Crude Aqueous Methanolic Extract Produced from Leaves of Eucalyptus species

Objectives:To evaluate the antimicrobial activity of the aqueous methanolic extract was given by the leaves of Eucalyptus sp.growing in Thi-Qar Province, south of Iraq. Additionally, to detect the compounds within the extract by using the technique of gas chromatography-mass spectrometry (GC-MS). Methodology: The healthy leaves of Eucalyptus sp. were collected, washed with tap water then by distilled water, dried, and pulverized through using a small mill to make the dried leaves as a powder. The leaves powder was extracted by absolute petroleum ether then aqueous methanol (80%) for obtaining a sticky crude extract of the aqueous methanol filtrate. The crude extract was tested against some microbial pathogens as well as analysis of the extract using the technique of GC-MS and phytochemical tests. Results:The current study showed the antimicrobial activity of the crude aqueous methanolic extract obtained from Leaves ofEucalyptus sp. by which 40000 µg∕ml of the extract exhibited inhibition zones around Staphylococcus aureus, Streptococcus mutans, Escherichia coli, and Klebsiella sp. besides Candida albicans that the inhibition zones were measured to be 30, 27, 26, 30, and 38 mm respectively. The chemical tests appeared the crude extract containsalkaloids, glycosides, flavonoids, tannins, andsaponin glycosides. GC-MS analysis detected constituents of the extract are dimethylsulfoxoniumformylmethylide, diethyl phthalate, benzene,1,1'-(1,2-cyclobutanediyl)bis-trans-,diisoctyladipate, and 2-methyl-7-phenylindole. Conclusion: The present study concluded that the leaves ofEucalyptussp. possess the bioactive products which are needed to be separatedas the pure compoundsby using techniques of chromatography in order to separately tested in vitro and in vivo, then application of spectrometry techniques for characterization of their chemical structure. Finally, these compounds can be used to treat diseasesas drugs in hospitals.

Emission analysis of recycled tire rubber modified asphalt in hot and warm mix conditions.

The hazardous emissions of crumb rubber (CR) modified asphalt during construction has been a concern for a long period. This study aims to identify the emission components in the CR modified asphalt in traditional hot mix asphalt (HMA) and with recently developed warm mix asphalt (WMA). The dynamic headspace gas chromatography-mass spectrometry (GCMS) was employed for identifying the emission of asphalt binders at 120°C, 140°C and 160°C. The coupling of gas chromatography and Fourier-transform infrared spectroscopy (GC-FTIR) was used to analyze the emission during the plant mixing for conventional HMA, CR-HMA and CR-WMA. The results showed the emission amount was highly dependent on mixing temperature. The warm mix technology can reduce the emission level significantly and should be encouraged in the asphalt mixture containing CR. Asphalt source and other extra additives in producing CR modified asphalt can also affect the emission significantly. Asphalt mixture containing CR can release toxic emissions such as xylene and toluene significantly higher compared to that without CR. In addition, it was found that the emission amount from the GCMS test for asphalt binder was lower than that in the field test for asphalt mix due to the thin asphalt film of asphalt mix.

CHARACTERIZATION OF SACCHARIDE SUGAR IN CORN SEED (Zea Mays Saccharata) BY USING GAS CHROMATOGRAPHY MASS SPECTROMETRY METHOD

This study characterizes the saccharide sugar contained in whole sweet corn seeds by extracting using Ultrasound Assisted Solvent Extraction for 60 minutes with 24 kHz frequency using ethanol solvent with concentrations of 70%, 75%, 80%, and 85%. The concentrated extract was then characterized by using Gas Chromatography Mass Spectrometry (GCMS) method. Sample test conducted were tested to odor, color and shelf life of extract and determination of water content, ash content, and characterization of saccharide sugar from GCMS test. The odor and color test results show that the extract had a distinctive smell of sweet corn, yellow, and had the ability to store good extract in the condition of the room. The water content of each sample ranged from 3% - 9% with the lowest water content was in 85% concentration sample which was 3.62%, while the ash content ranged from 1.5% with the highest ash content which was in 85% concentration sample which was 1.59%. The results of characterization were identified by 3 compounds having the highest percentage of 2-Furaldehyde, Hexamethyl Cyclotriloxane, and 1,2,4-Trimethyl Benzene with the percentage of 26,94%, 9,95% and 13,82% respectively. 2-Furaldehyde includes heterocyclic aldehyde group sugars, whereas Hexamethyl Cyclotriloxane and 1,2,4-Trimethyl Benzene belong to the class of organosilicon and aromatic hydrocarbons. 2-Furaldehyde or Furfural serves as a tongue nerve stimulator and has great potential to be developed as an important non-petroleum-based chemical raw material. The GCMS results provide information that the obtained 2-Furaldehyde has a molecular formula C5H4O2 or C4H3OCHO which is a monosaccharide group which is aldose with the number of C atoms classified as pentose. The retention time was 3.062 minutes with a mass peak of 300 m/z with molecular weight was 96 g/mol.

Screening for active compounds in &lt;italic&gt;Rhus coriaria&lt;/italic&gt; L. crude extract that inhibit the growth of &lt;italic&gt;Pseudomonas syringae and Ralstonia solanacearum&lt;/italic&gt;

An experiment was performed to study the antibacterial activity of methanol, acetone, alcohol and aqueous extracts from the fruit of &lt;italic&gt;R. coriaria&lt;/italic&gt; by disk diffusion assay in terms of minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC) and killing-time curve. The detection of the components was also fulfilled using Gas Chromatography–Mass Spectrometry (GC-MS) and also tested for their antibacterial activity. The tested bacteria were &lt;italic&gt;Pseudomonas syringae&lt;/italic&gt; (Accession No. KJ858057), a tomato bacterial speck causal agent, and &lt;italic&gt;Ralstonia solanacearum&lt;/italic&gt; (Accession No. KJ881159) causing tomato bacterial wilt. Furthermore, the inhibition criteria were made by different extracts of the sampled bacteria which were measured and compared with standard antibiotic (chloramphenicol). Aqueous extract displayed better outcomes against &lt;italic&gt;P. syringae&lt;/italic&gt; and &lt;italic&gt;R. solanacearum&lt;/italic&gt; as compared to chloramphenicol. According to the GC-MS test results, the aqueous extract was composed of 39 different phytocompounds, together with eight elements in the high peak region, namely Furfural, 1-Cyclopetene, 2,5 Furandione, Phloroglucinol, Succinic acid, Malic acid, P-Tolylacetic acid and Coumalic acid. Among these, it was discovered that 2,5 Furandione was the most important antibacterial element that is present in sumac. The results from the current study indicate that different extracts of &lt;italic&gt;R. coriaria&lt;/italic&gt; contain a variety of antibacterial compounds which can potentially be used to produce an extensive range of herbal mixtures with anti-bacterial properties for controlling diseases in crops belonging to the &lt;italic&gt;Solanaceae family&lt;/italic&gt;.

Component Analysis of Deposits in Selective Catalytic Reduction System for Automotive Diesel Engine

In this paper, deposits in exhaust pipes for automotive diesel engines were studied by various chemical analysis methods and a kind of analysis process to determine the compositions of organic matter was proposed. Firstly, the elements of the deposits were determined through the element analysis method. Then using characteristic absorption properties of organic functional groups to the infrared spectrum, the functional groups in the deposits were determined. Finally, by GC-MS (gas chromatography - mass spectrometry) test, the content of each main component was determined quantitatively. Element analysis results indicated that the deposits adsorbed metal impurities from fuel oil, lubricating oil, mechanical wear and urea water solution. The result of GC-MS test showed that the area percentage of cyanuric acid was the biggest (about 85%), the second was urea (about 4%), and the content of biuret and biurea was scarce.

Evaluation of the Usefulness of An Oxycodone Immunoassay in Combination with a Traditional Opiate Immunoassay for the Screening of Opiates in Urine

Oxycodone is a semisynthetic opioid analgesic largely prescribed for post-operative and chronic pain management. The introduction of a slow release formulation of oxycodone has led to its frequent abuse and to an increase in emergency cases related to oxycodone overdose. Until recently, oxycodone testing has been confined to gas chromatography-mass spectrometry (GC-MS) analysis because the widely used automated opiate immunoassays poorly react to this compound. We investigated the utility of a new oxycodone immunoassay as a screening procedure to eliminate inappropriate GC-MS testing of negative urine specimens. We analyzed 96 urine specimens using GC-MS and two immunoassays, CEDIA((R)) opiates and DRI((R)) oxycodone assays from Microgenics, on a Hitachi 917 analyzer. The GC-MS allowed us to detect codeine, hydrocodone, hydromorphone, morphine, oxycodone, and oxymorphone following enzymatic hydrolysis and derivation by acetylation. The combination of the two immunoassays gave the best performance (98% sensitivity and specificity) when considering a positive result from GC-MS for any of the opiates. Considering positive GC-MS results for oxycodone or oxymorphone only, the oxycodone immunoassay resulted in two false-positives and one false-negative (50 ng/mL cutoff). Using these immunoassays for screening before GC-MS analysis provides a reduced opiate GC-MS workload without compromising quality.

Tapetum Degeneration Retardation is Critical for Aliphatic Metabolism and Gene Regulation during Rice Pollen Development

As a complex wall system in flowering plants, the pollen outer wall mainly contains aliphatic sporopollenin; however, the mechanism for synthesizing these lipidic precursors during pollen development remains less well understood. Here, we report on the function of the rice tapetum-expressing TDR (Tapetum Degeneration Retardation) gene in aliphatic metabolism and its regulatory role during rice pollen development. The observations of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses suggested that pollen wall formation was significantly altered in the tdr mutant. The contents of aliphatic compositions of anther were greatly changed in the tdr mutant revealed by GC-MS (gas chromatography-mass spectrometry) testing, particularly less accumulated in fatty acids, primary alcohols, alkanes and alkenes, and an abnormal increase in secondary alcohols with carbon lengths from C29 to C35 in tdr. Microarray data revealed that a group of genes putatively involved in lipid transport and metabolism were significantly altered in the tdr mutant, indicating the critical role of TDR in the formation of the pollen wall. Also, a wide range of genes (236 in total-154 up-regulated and 82 down-regulated) exhibited statistically significant expressional differences between wild-type and tdr. In addition to its function in promoting tapetum PCD, TDR possibly plays crucial regulatory roles in several basic biological processes during rice pollen development.

Performance Characteristics of 7-Aminoflunitrazepam Specific Enzyme-Linked Immunosorbent Assays

With 7-aminoflunitrazepam (7-amino-FM2)-specific ELISAs now readily available from several commercial sources (e.g., Cozart Bioscience, Immunalysis, this study was conducted to evaluate the performance characteristics of these products when applied to the two-step testing protocol as commonly practiced in today's workplace drug-testing programs. Cross-reacting characteristics of these two assays toward a list of 25 benzodiazepines were evaluated. These assays were then applied to the analysis of urine specimens collected from patients treated with flunitrazepam (FM2) and/or other benzodiazepines. Resulting data were evaluated against gas chromatography-mass spectrometry (GC-MS) test data to ascertain corresponding cutoffs suitable for the two-step immunoassay/GC-MS testing strategy. Both Cozart and Immunalysis ELISAs are highly specific to 7-amino-FM2, with the latter reagent generating slightly higher responses. Diazepam and FM2 (parent compound) are the only compounds with significant cross-reacting characteristics. With the ELISA reagents' optimal dynamic ranges set between 0 and 25 ng/mL, urine specimens should be diluted by a factor of 5 prior to ELISA testing. If 30 ng/mL 7-amino-FM2 is adapted as the GC-MS cutoff, the corresponding ELISA cutoffs range is approximately 100-200 (or 20-40 when diluted by a factor of 5) ng/mL. Reagent lot and specimen characteristics (with or without the presence of cross-reacting compounds) affect the correlation of data derived from ELISA and GC-MS tests.

Enantiomeric Separation and Quantitation of ( )-Amphetamine, ( )-Methamphetamine, ( )-MDA, ( )-MDMA, and ( )-MDEA in Urine Specimens by GC-EI-MS after Derivatization with (R)-(-)- or (S)-(+)- -Methoxy- -(trifluoromethy)phenylacetyl Chloride (MTPA)

In drug testing, the presence of methamphetamine in urine is generally confirmed by a gas chromatography-mass spectrometry (GC-MS) method. Derivatization of the compound to a perfluoroalkylamide, prior to confirmation, typically yields better chromatographic separation. Once methamphetamine is detected, a second GC-MS test is necessary to distinguish positive results from the use of over-the-counter medication, Vicks inhaler, or from use of a prescription drug, selegiline (Deprenyl). R-(-)-Methamphetamine is the urinary product from legitimate use of these medications. The second GC-MS test is to confirm illicit use of (S)-(+)-methamphetamine. In the procedure, the two methamphetamine isomers are changed to the chromatographically separable diastereomers by a chiral derivatizing agent, (S)-(-)-trifluoroacetylprolyl chloride (TPC). But the method has inherent limitations. Racemization of the reagent produces mixed diastereomers even from pure (S)-(+)-methamphetamine. Instead of using TPC, we utilized (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride (MTPA) to prepare the amides of diastereomers of methamphetamine. No racemization was observed with this reagent. The method was extended to resolve GC peaks of (R)-(-)- and (S)-(+)-isomers of amphetamine, 3,4-methylenedioxyamphetamine (MDA), N-methyl-MDA (MDMA), and N-ethyl-MDA (MDEA). Three ions from the drug and two ions from the deuterated internal standard were monitored to characterize and quantitate the drugs. For MDEA, only one ion was used. The quantitation was linear over 25 to 5000 ng/mL for MDEA and 25 to 10,000 ng/mL for all other drugs. Correlation coefficients were > 0.996. Precision calculated as the coefficient of variation at the calibrator concentration of 500 ng/mL was within +/- 11% for all drugs. The method was applied to test 43 urine specimens. In 91% of the methamphetamine-positive specimens, only the (S)-(+)-isomer was detected. In all MDMA-positive specimens, the concentrations of (R)-(-)-isomer were greater than the (S)-(+)-isomer indicating longer retention of (R)-(-)-isomer in the human body. The specimen concentrations (R + S) compared well with that of a non-chiral method that used 4-carboethoxyhexafluorobutyryl chloride as derivatizing agent. But the MTPA method has some advantage. It alone can replace the two GC-MS methods needed to confirm the presence of (S)-(+)-isomers of amphetamine and methamphetamine.

Screening for Neuroblastoma at 3 Weeks of Age: Methods and Preliminary Results From the Quebec Neuroblastoma Screening Project

A large neuroblastoma screening study was recently started in the province of Quebec, Canada. This project, a collaboration between the Quebec Network for Genetic Medicine and the University of Minnesota, is studying the impact of screening infants for the preclinical detection of neuroblastoma on the population-based mortality caused by this tumor. All infants born in Quebec during a 5-year period will be screened twice, at 3 weeks and at 6 months. Urinary homovanillic acid and vanillylmandelic acid determination from dried filter paper samples is used for screening. Initial qualitative screening is done by means of thin-layer chromatography with confirmatory quantitative screening by gas chromatography-mass spectrometry (GC-MS). During the initial 6 months of 3-week screening, 41,673 neonates (92% compliance rate) were screened and 10.6% of them were tested also by GC-MS. Nine of these neonates had positive results on two GC-MS tests and were referred for evaluation to rule out the presence of neuroblastoma. Four had the tumor, 1 had a calcified adrenal gland, and 4 had no tumor detected. Three additional neonates had clinical diagnosis of neuroblastoma before they reached the screening age of 3 weeks. A neuroblastoma that did not secrete homovanillic acid or vanillylmandelic acid was diagnosed clinically in 1 additional patient who tested negative by screening.