Gas chromatography with mass spectrometry detection and characterization of 27 sterols in two truffle (Tuber) species

Fungal sterols (mycosterols) were investigated in seven samples of both Tuber aestivum and Tuber borchii truffles from Italy, Spain and Romania by means of gas chromatography with mass spectrometry (GC/MS). Sterol contents varied from 130 to 590 mg/100 g dry weight (T. borchii) and 110−420 mg/100 g dry weight (T. aestivum). The sterol pattern of both truffle species was dominated by ergosterol (60–85 %) and brassicasterol (4–33 %). In addition, 25 minor sterols were detected with 27 (n = 3), 28 (n = 17), 29 (n = 3), 30 (n = 2) and 31 (n = 2) carbon atoms (Limit of detection: 2 μg/100 g dry weight). Fourteen minor sterols were described for the first time in Tuber species. Ten minor compounds were detected in all samples in varying abundances, while the others were (i) exclusively detected in all samples of one species (T. borchii: fecosterol, ergosta-8-enol; T. aestivum: 24-methyleneergosta-5,22,24-trienol) or (ii) varied strongly in abundance (≥90 %). Variations in main and selected minor sterols could be partly related to different harvest times. In addition, differences in fungisterol and ergosta-5,7-dienol between the both species were attributed to different pathways in fungal sterol biosynthesis (oneway ANOVA p ≤ 0.01). Our study indicates that sterol pattern analysis could be used to differentiate different Tuber species.     

Study of mercury content in wild edible mushrooms and its contribution to the Provisional Tolerable Weekly Intake in Spain

The study determined total mercury (Hg) content of 10 wild edible mushroom species collected in southern Spain. Results indicated that the highest Hg level corresponded to Boletus aereus with 10.28 ± 2.92 mg/kg DW (dry weight), while the lowest Hg level was found in Terfezia arenaria with 0.09 ± 0.08 mg/kg DW. Regarding the anatomic parts of the mushrooms, caps showed significantly higher Hg concentrations than stems in B. aereus, Amanita caesarea and Macrolepiota procera. The percentage of contribution to the Provisional Tolerable Weekly Intake (PTWI) for Hg was also calculated. Based on consumption data in Spain (0.011 kg/person/week), %PTWI was calculated ranging between 0.06 and 3.5% for mean Hg levels. When a high level of consumption was assumed (0.100 kg/person/week), %PTWI ranged between 0.58 and 31%. Results suggest that wild edible mushrooms in southern Spain could contribute with high Hg levels to the Spanish diet. However, the lack of consumption data for wild edible mushrooms made it difficult to give more definitive conclusions; hence further studies including specific consumption data will be needed.     

Isolation and determination of lipophilic mycochemicals from a New Zealand edible native mushroom Hericium novae-zealandiae

Hericium novae-zealandiae is a native mushroom consumed by indigenous Māori people in New Zealand. The lipophilic mycochemicals of the mushroom were isolated using a normal column chromatography combined with a preparative HPLC. Structural characterisation based on spectroscopic methods, namely UV, MS, NMR and single crystal XRD have identified three lipophilic compounds as hericene B (a compound unique to Hericium), ergosterol and ergosterol peroxide. Following this, an HPLC-DAD method was developed and validated to quantify the hericene B and ergosterol. The method showed excellent selectivity, linearity, precision, accuracy and robustness. The content of hericene B was determined as 28.53 mg/g by dry weight of H. novae-zealandiae (approximately 3%). This discovery indicates the potential utilisation of H. novae-zealandiae as a natural source of hericene B. Current research revealed for the first time, the lipophilic constituents of H. novae-zealandiae and the method development for quantification of hericene B in the above species.     

Blood concentrations of carbon disulphide in dithiocarbamate exposure and in the general population

Summary Blood carbon disulphide (CS₂), both free and total, was determined by gas chromatography-mass spectrometry in 112 normal subjects and in 20 subjects employed in a dithiocarbamate factory, comprising ten blue-collar workers involved in dithiocarbamate production and ten white-collar office staff. The ten production workers were examined over two workshifts, the first at the beginning of the week (Monday) and the second after an intervening period of at least 1 day. Three blood samples were taken for each shift studied, one prior to starting work, one at the end of the shift and the third 16 h after the end of the shift (on the following morning). The mean CS₂ blood levels measured in the 112 normal subjects was 663 ng/l for the free fraction and 3178 ng/l for the total. In 16 blood samples taken from the ten dithiocarbamate factory office workers, the mean free and total CS₂ blood levels were 846 and 4140 ng/l, respectively, i.e. not significantly different from those observed in the normal subjects. At the end of the first 8-h shift, the ten dithiocarbamate factory production workers had free and total CS₂ values of 1070 and 8471 ng/l, respectively, which were significantly higher than those observed prior to starting work (240 and 4738 ng/l). All the total CS₂ levels measured in the shop-floor workers, with the sole exception of the values recorded prior to the start of the Monday shift (4738 ng/l), ranged from 7047 to 8471 ng/l and were significantly higher than those measured in the white-collar staff (4140 ng/l).     

On-line monitoring of benzene air concentrations while driving in traffic by means of isotopic dilution gas chromatography/mass spectrometry

There is no shortage of information about the average benzene concentrations in urban air, but there is very little about microenvironmental exposure, such as in-vehicle concentrations while driving in various traffic conditions, while refuelling, or while in a parking garage. The main reason for this lack of data is that no analytical instrumentation has been available to measure on-line trace amounts of benzene in such situations. We have recently proposed a highly accurate, high-speed cryofocusing gas chromatography/mass spectrometry (GC/MS) system for monitoring benzene concentrations in air. Accuracy of the analytical data is achieved by enrichment of the air sample before trapping, with a stable isotope permeation tube system. The same principles have been applied to a new instrument, specifically designed for operation on an electric vehicle (Ducato Elettra, Fiat). The zero emission vehicle and the fully transportable, battery-operated GC/MS system provide a unique possibility of monitoring benzene exposure in real everyday situations such as while driving, refuelling, or repairing a car. All power consumptions have been reduced so as to achieve a battery-operated GC/MS system. Liquid nitrogen cryofocusing has been replaced by a packed, inductively heated, graphitized charcoal microtrap. The instrument has been mounted on shock absorbers and installed in the van. The whole system has been tested in both fixed and mobile conditions. The maximum monitoring period without external power supply is 6 h. The full analytical cycle is 4 min, allowing close to real-time monitoring, and the minimum detectable level is 1 g/m³ for benzene. In-vehicle monitoring showed that, when recirculation was off and ventilation on, i.e., air from outside the vehicle was blown inside, concentrations varied widely in different driving conditions: moving from a parking lot into normal traffic on an urban traffic condition roadway yielded an increase in benzene concentration from 17 to 62.3 g/m³ even if the actual distance was small. A larger increase was observed when a car was left with the engine running at a distance 2 m from the zero emission vehicle: We measured an increment of benzene concentrations from 15.2 to 174.4 g/m³ with a car equipped with a catalytic converter, and from 19.1 to 386.3 g/m³ with a car without such a converter.     

Application of metabolic profiling to study the effects of ethanol on metabolism in rats

Rat urine was analyzed by both gas chromatography and a combination of gas chromatography/mass spectroscopy in an attempt to apply the technique of metabolic profiling to determine if ethanol consumption produced an alteration in acid excretion products. Rats were fed a liquid diet for seven days then fed ethanol in the same diet. The 24 hr urine for the last day of control and the first day of ethanol differed greatly with respect to four compounds. These were an increase in threonic, glucuronic and an undetermined acid and a decrease in pyroglutamic acid. The biological basis for the alterations was not investigated. Glucuronic acid forms conjugates with many compounds. Possibly an acute dose of ethanol may alter the removal of some compounds from the liver.     

固相萃取-气质联用法测定水中三氯杀螨醇及百菌清

目的:建立了水中多种拟除虫菊酯类农药残留的固相萃取-气相色谱-质谱(GC/MS)联用检测方法。方法:采用C18固相萃取碟富集吸附水样中目标组分,以二氯甲烷洗脱浓缩; DB-5MS毛细管柱分离,采用选择离子监测SIM的质谱扫描模式进行定性定量分析。结果:在50~400μg/L浓度范围内线性关系良好,相关系数均>0 .995,三氯杀螨醇、百菌清加标平均回收率为90 .0% ~101 .1%,方法的相对标准偏差为4. 2% ~8. 3%,水样浓缩2 .500倍的最低检测限分别为0 .0012、0. 0024μg/L。结论:本法具有非常高的选择性、灵敏度和准确度,完全能满足水中痕量三氯杀螨醇及百菌清的分析。     

Biological monitoring of isocyanates and related amines

Summary 1,6-Hexamethylene diamine (HDA), used as raw material in industrial manufacturing operations, was orally administered to six healthy volunteers. After acid hydrolysis of the urine by hydrochloric acid, HDA and the metabolite 6-aminohexanoic acid were quantified. HDA was determined as an ethyl-chloroformate derivative by capillary gas chromatography using thermionic specific detection (TSD), and 6-aminohexanoic acid was quantified by ion chromatography using the ninhydrin reaction. In nonhydrolysed urine, monoacetylated HDA (N-acetyl-1,6-hexamethylene diamine) and HDA, were verified as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry (GC-MS), in a chemical ionization mode using isobutane and ammonia as reagent gases. In hydrolysed urine, a mean of 0.28 mg (range 1–6%) of the administered dose (8.2 mg) was recovered as HDA, and a mean of 0.8 mg (range < 1–27%) as 6-aminohexanoic acid. The urinary excretion of both the determined compounds was rapid, and the principal part (> 90%) of the elimination was completed within 10 h. There was a considerable inter-individual variation in the excreted amounts, but the intra-individual variation in the excretion of HDA was limited. The subjects N-acetylator phenotype was determined by a dapsone test. Three slow acetylators excreted lower amounts (mean 2% of given dose) of HDA than three rapid ones (mean 5%).     

不饱和脂肪酸的气相色谱法同时测定

目的：建立不饱和脂肪酸含量的测定方法。方法：采用衍生气相色谱程序升温同时测定4个成分。结果：平均回收率为95％～105％，RSD为0．39％～2．81％。结论：该方法可以用于保健品及食品中不饱和脂肪酸的测定。     

The determination of polycyclic aromatic hydrocarbons in smoked fish by gas chromatography mass spectrometry with positive-ion chemical ionization

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants representing an important group of carcinogens that have been detected in smoked fish. The levels of six PAHs (benzo[a]pyrene, benz[a]anthracene, benzo[k]fluoranthene, benzo[b]fluoranthene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene) were determined in 97 various samples of smoked fish, 11 samples of fresh fish, and 18 olive- and 14 rape-oil samples. For cleaning of the sample, a gel chromatography was used. PAHs were separated by gas chromatography and detected by positive-ion chemical ionization using ammonia as reagent gas. The HP 6890 Plus GC/HP 5973 MSD with positive-ion chemical ionization option was used in the selected ion-monitoring mode. The limit of detection for PAHs using this method was approximately 0.3 ppb with about 75% recovery. The results were confirmed by high-pressure liquid chromatography. The samples of domestic (Estonian) smoked fish was analyzed during 2003–2004, the sum of the average of six PAHs content was found to be 12.37 μg kg⁻¹, and in samples of fresh fish it was not detected.     

Determination of total phenol content, antioxidant activity and acetylcholinesterase inhibition in selected mushrooms from Turkey

In the present study, we investigated the acetylcholinesterase (AChE) inhibitory activity of the ethanolic extracts of a number of mushroom species growing in Turkey, including mainly Polyporus species (Polyporus gilvus, Polyporus sulphureus, Polyporus annosus, Polyporus radiatus, Polyporus pinicola, Polyporus volvatus, Polyporus fomentarius, Polyporus stevenii, Polyporus badius), as well as Cantharellus cibarius, Lactarius deliciosus, and Trametes versicolor. The analyses were carried out using the spectrophotometric method of Ellman in ELISA microplate reader at 500 μg/ml. Since Alzheimer's disease (AD) is associated with oxidative degeneration of cells, several methods of antioxidant activity were applied to the mushroom extracts such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelating effect, ferric-reducing antioxidant power (FRAP), and beta-carotene bleaching tests. Total phenol contents of the extracts were also determined by Folin-Ciocalteu reagent. In anti-AChE assay, the most active one was P. sulphureus having 31.44% of inhibition. P. voluatus showed the best scavenging effect against DPPH, while all of the extracts exerted low capacity in chelating ferrous ions and reducing ferric ion.     

气相色谱-质谱法测定自来水中15种有机污染物

目的:探讨气相色谱-质谱法测定自来水中15种有机污染物的分析方法。方法:自来水中的15种有机污染物经过C18固相萃取柱富集,用乙酸乙酯和二氯甲烷洗脱浓缩,DB-5MS毛细管色谱柱分离,气相色谱-质谱联用仪检测,采用全扫描和选择离子方式同时扫描,通过目标组份的质谱图和保留时间与标准品的的质谱图和保留时间作对照进行定性,内标法单离子定量。结果:样品加标回收率在72%～130%之间,相对标准偏差在1.00%～4.35%之间,检出限在0.0014μg/ml～0.045μg/ml之间。结论:实验结果表明,该方法除测定苯并[α]芘检出限较高外,测定其它14种有机污染物的各项技术指标均能满足检测要求。     

Changes in intakes of total and added sugar and their contribution to energy intake in the U.S

This study was designed to document changes in total sugar intake and intake of added sugars, in the context of total energy intake and intake of nutrient categories, between the 1970s and the 1990s, and to identify major food sources contributing to those changes in intake. Data from the NHANES I and III were analyzed to obtain nationally representative information on food consumption for the civilian, non-institutionalized population of the U.S. from 1971 to 1994. In the past three decades, in addition to the increase in mean intakes of total energy, total sugar, added sugars, significant increases in the total intake of carbohydrates and the proportion of carbohydrates to the total energy intake were observed. The contribution of sugars to total carbohydrate intake decreased in both 1-18 y and 19+ y age subgroups, and the contribution of added sugars to the total energy intake did not change. Soft drinks/fluid milk/sugars and cakes, pastries, and pies remained the major food sources for intake of total sugar, total carbohydrates, and total energy during the past three decades. Carbonated soft drinks were the most significant sugar source across the entire three decades. Changes in sugar consumption over the past three decades may be a useful specific area of investigation in examining the effect of dietary patterns on chronic diseases.     

串联质谱和气相色谱技术在新疆地区高危儿遗传代谢病临床筛查诊断中的应用研究

目的应用串联质谱和气相色谱技术对新疆地区高危儿遗传代谢病结果进行分析,了解该地区遗传代谢病的发病率、临床特点,为临床医师提供诊疗依据。方法选取2014年1月-2019年4月该院临床上高度怀疑遗传代谢病的高危儿2500例为研究对象,应用气相色谱和串联质谱方法进行血液和尿液分析。结果2500例患儿中检测出219阳性病例(阳性率为8.76%),其中男119例,女100例。新生儿期发病80例(36.53%),<1岁84例(38.36%),1~12岁55例(25.11%),并且通过检测发现氨基酸、有机酸及脂肪酸氧化代谢病共18项病种。其中各种氨基酸水平高118例(53.88%),各种有机酸水平高84例(38.36%),各种脂肪酸氧化缺陷病17例(7.76%)。结论临床上通过临床表现及各种实验室检查不能明确病因的疑似遗传代谢病的高危患儿应用串联质谱和气相色谱技术进行筛查可及时发现遗传代谢病患儿,从而得到早期诊断及治疗,降低死亡率、致残率,减轻家庭负担,提高优生优育率,值得临床推广应用。     

食品中丙烯酰胺分析方法的研究进展

从2002年首次发现某些食品中含有可能致癌物丙烯酰胺后,世界卫生组织和各国研究机构高度重视,开始研究不同的检测方法,降低其含量的有效措施,开发安全、方便,适用于食品生产和家庭烹饪的制作程序。食品中丙烯酰胺的研究进展情况,包括丙烯酰胺的分析方法、食品源、暴露量、形成机制和含量控制的措施。为此,对为该问题的进一步深入研究提供一些基础资料。     

液相色谱-串联质谱法检测水中微囊藻毒素LR和RR

目的:建立水中微囊藻毒素LR和RR的液相色谱-串联质谱检测方法。方法:水样经C18固相萃取小柱富集,甲醇洗脱,浓缩后,经XTerra MS C18(2.1×150 mm,5μm)柱进行色谱分离,采用多反应监测(MRM)模式对微囊藻毒素进行检测,外标法定量。结果:微囊藻毒素LR和RR的检出限分别为0.002μg/L和0.001μg/L,其加标回收率分别为84.6%～90.6%和86.6%～91.2%,相对标准偏差小于5.0%。结论:该方法用水量少,简便、快速、准确,适用于水中微囊藻毒素LR和RR的检测。     

吹扫捕集-气质联用法测定广州市萝岗区井水中挥发性有机物

目的:应用吹扫捕集-气质联用技术,对广州市萝岗区井水中可能存在的挥发性有机污染物进行定性定量检测。方法:吸取样品溶液5 ml,在40℃条件下吹扫捕集11 min,190℃脱附4 min,经Rxi-5ms毛细管柱分离,电子轰击电离(EI)全扫描检测。结果:用该法检测井水中54种挥发性有机物,检出限为0.10μg/L～0.25μg/L,样品加标回收率为83.9%～114.5%,相对标准偏差为2.85%～9.67%。结论:用吹扫捕集-气质联用法测定井水中挥发性有机化合物,方法简便可靠,测定结果表明广州市萝岗区井水水质良好,仅部分井水检测出少量挥发性有机物。     

中山市市售猪肉(含猪内脏)残留禁用化学药品的现状及控制的研究

目的 掌握中山市市售猪肉（含猪内脏）受禁用化学药品污染的现状，提出相应的预防和控制措施，方法 采用分层按比例抽样的方法，分别对中山市的港口镇，三乡镇，沙溪镇，小榄镇，石岐城区共80份市售猪肉（含猪内脏）进行调查，采用气质联用法（GC/MS）检测，鉴别其中含有禁用化学药品的成分。结果 此次调查80个样品共检出禁用化学药品有3种，残留阳性样品5个，总残留阳性率为6.3%。其中盐酸克仑特罗阳性检出率为5.0%，N，N-二甲基硫脲和甲巯基咪唑阳性检出率均为1.3%。盐酸克仑特罗阳性样品全部来自小榄镇，N，N-二甲基硫脲和甲巯基咪唑阳性样品则来自石岐城区，港口镇，三乡镇，沙溪镇均未检出阳性样品，结论 中山市市售猪肉（含猪内脏）残留的禁用化学药品主要是盐酸克仑特罗，但也检出了N，N-二甲基硫脲和甲巯基咪唑，禁用化学药品只在部分区域内检出，因此首要任务是加强对盐酸克仑特罗的监测，同时也要警惕其它禁用化学药品的存在，在对全市的生猪市场进行监测管理时，应着重管理存在问题的地区。     

Measurement of the urinary metabolites of n-hexane,cyclohexane and their isomers by gas chromatography

Summary A gas chromatographic method for analyzing the urinary metabolites of n-hexane (2-hexanol, 2,5-hexanedione, 2,5-dimethylfuran and -valerolactone), of 2-methylpentane (2-methyl-2-pentanol), of 3-methylpentane (3-methyl-2-pentanol), and of cyclohexane (cyclohexanol) was developed. Processing of urine and the gas chromatographic conditions are described. The recovery rate of all hexane metabolites, except 2,5-dimethylfuran, ranged between 92 and 100%. The variation coefficient of metabolites determination was between 1.5 and 5%, apart from 2,5-dimethylfuran determination for which the variation coefficient was 15%. The detection limits ranged between 0.2 and 0.7 mg/1 and between 0.05 and 0.1 mg/1 when a packed or capillary column was used. Results obtained from a packed and capillary column are discussed.