Characterization of polar urinary metabolites by ionspray tandem mass spectrometry following dansylation

The present report illustrates the application of dansyl chloride coupled with ion spray tandem mass spectrometry (IS-MS/MS) in identifying polar urinary metabolites. In the course of the metabolism studies of a drug that is currently in development, the urine from rats and dogs was collected following oral administration of radiolabelled compound. Urinary metabolic profiles of the rat and dog indicated the presence of four major peaks and one major peak, respectively, in the radiochromatogram. Since all attempts to identify the peaks by conventional MS/MS techniques failed, the metabolites were isolated by fraction collection and dansylated. Derivatization of the metabolites resulted in the formation of more hydrophobic, readily ionizable species which were more sensitive in IS-MS/MS analysis than the underivatized metabolites. Examination of the molecular ions and the product ion mass spectra of these derivatives revealed the structures of all the urinary metabolites. The metabolites in the rat and the dog were 4-hydroxyphenylpiperazine glucuronide (M1), 1,4-dihydroxyphenyl glucuronide (M2), 1,4-dihydroxyphenyl sulfate (M3) and phenylpiperazine (M4). Thus, derivatization with dansyl chloride in conjunction with tandem mass spectrometry is a useful tool in identifying polar urinary metabolites.     

Non-covalent complexes between DNA-binding drugs and double-stranded deoxyoligonucleotides: a study by ionspray mass spectrometry

The non-covalent complexes between some DNA-binding drugs and duplex oligodeoxynucleotides were studied by ionspray mass spectrometry, with the aim of evaluating the suitability of this technique to screen rapidly a series of drugs exerting their activity through non-covalent binding to specific base sequences of DNA. Two classes of drugs were considered, distamycins (which show affinity for the minor groove of DNA) and anthracyclines (which interact through intercalation between bases). For the former, d(CGCGAATTCGCG)2 was chosen as the model oligodeoxynucleotide. Following optimization of sample preparation and instrumental conditions, the complexes of different distamycins were observed; depending on the ligand considered, 1:1 or 2:1 complexes were formed preferentially. A semi-quantitative evaluation of the relative affinities was made by measuring the ratio of the complexes signals to those of the duplex, and also by competitive binding with equimolar amounts of distamycin. For anthracyclines, the daunorubicin-d(CGATCG)2 complex was chosen as the model for a preliminary mass spectrometric study; however, the signals of the duplex and the complex were very low compared with the monomer signal. Since the complex was known to be stable in solution, this was ascribed to gas-phase instability, probably caused by electrostatic repulsion between negatively charged phosphate groups.     

流动注射在线共沉淀火焰原子吸收光谱法测定氯化钴溶液中痕量铅

为解决钴冶金生产中痕量铅的快速监控问题, 将流动注射在线富集分离技术与火焰原子吸收光谱检测方法相结合测定了氯化钴溶液中痕量铅。研究了铅的富集和分离条件, 结果表明, 用填充脱脂棉的微型锥形过滤器作为过滤柱, 以硝酸铁作为共沉淀剂, 在pH10的氨性缓冲介质中铁和铅生成氢氧化物共沉淀, 富集在过滤柱上, 可与高钴基体分离, 过滤柱上铅经盐酸（1+9）洗脱后用火焰原子吸收光谱法测定。在283.3nm波长处测得铅的特征浓度为0.008mg/L（1%吸收）, 检出限为5μg/L, 样品中铅测定结果的相对标准偏差为6.1%（n=11）, 满足了快速分析的要求。     

流动注射-原子光谱法分析铬价态研究进展

对流动注射在线富集-原子光谱法用于铬价态分析的研究进展进行了综述,内容包括Cr ,Cr 的预富集和流动注射-原子光谱法在状态分析中的应用。引用文献47篇。     

激光剥蚀-电感耦合等离子体质谱内标定量法测定高温合金中痕量元素

高温合金中痕量杂质对合金性能的严重影响而迫切需要对其含量进行准确测定,但由于样品成分复杂致使干扰严重,且其杂质含量极低,传统分析方法难以满足测定要求。本文采用激光剥蚀固体进样与电感耦合等离子体质谱技术对高温合金中近20种痕量元素进行分析。对分析条件进行了全面系统的优化,使高温合金中大多数痕量元素通过层层剥蚀的激光剥蚀过程被稳定地蒸发,从而顺利对低沸点杂质元素进行了测定。考察了各元素的干扰情况,比较了分别以71Ga,115In,205Tl或61Ni为内标时的校正作用,选取71Ga为内标,由高温合金标准样品建     

The determination of benzalkonium chloride in eye-drops by difference spectrophotometry

Faecal samples from 94 dairy cows and 42 calves in three different herds were examined by a variety of techniques for campylobacters. Cefoperazone amphotericin teicoplanin (CAT) agar, modified cefoperazone charcoal deoxycholate agar (mCCDA), Karmali agar, and membrane filtration onto blood agar, were used with and without enrichment in CAT broth. Seventy-nine percent of cattle in herd A carried campylobacters, compared with 40% and 37.5% of cattle in herds B and C, respectively. Most animals carried only one species of Campylobacter. Campylobacter hyointestinalis was isolated most frequently (32% animals positive) with Camp. fetus subsp. fetus and Camp. jejuni subsp. jejuni detected in 11% and 7% of animals, respectively. In addition, a novel biotype of Camp. sputorum was isolated from 60% of 47 cows tested in herd A. Direct plating detected only two of the total of 40 animals positive for campylobacter. Enrichment in CAT broth before membrane filtration onto blood agar or CAT agar were the most successful methods of plating. Campylobacter sputorum was isolated from CAT agar and blood agar but not from mCCDA or Karmali agar. Karmali agar incubated at 30 degrees C was especially effective for isolating Camp. fetus subsp. fetus.     

DNA sequence analysis by MALDI mass spectrometry

Conventional DNA sequencing is based on gel electrophoretic separation of the sequencing products. Gel casting and electrophoresis are the time limiting steps, and the gel separation is occasionally imperfect due to aberrant mobility of certain fragments, leading to erroneous sequence determination. Furthermore, illegitimately terminated products frequently cannot be distinguished from correctly terminated ones, a phenomenon that also obscures data interpretation. In the present work the use of MALDI mass spectrometry for sequencing of DNA amplified from clinical samples is implemented. The unambiguous and fast identification of deletions and substitutions in DNA amplified from heterozygous carriers realistically suggest MALDI mass spectrometry as a future alternative to conventional sequencing procedures for high throughput screening for mutations. Unique features of the method are demonstrated by sequencing a DNA fragment that could not be sequenced conventionally because of gel electrophoretic band compression and the presence of multiple non-specific termination products. Taking advantage of the accurate mass information provided by MALDI mass spectrometry, the sequence was deduced, and the nature of the non-specific termination could be determined. The method described here increases the fidelity in DNA sequencing, is fast, compatible with standard DNA sequencing procedures, and amenable to automation.     

Characterization of a synthetic 37-residue fragment of a monoclonal antibody against herpes virus by capillary electrophoresis/electrospray (ionspray) mass spectrometry and 252Cf plasma desorption mass spectrometry

A peptide comprising 37 amino acids of the antigen binding site of a monoclonal antibody directed against glycoprotein D of herpes simplex virus was synthesized. The synthetic peptide and the impurities formed in the synthesis were characterized by capillary electrophoresis/ionspray mass spectrometry and by 252Cf plasma desorption-time of flight mass spectrometry. The measured average molecular mass of the synthetic peptide was 4627.16 Da, which was only 0.08 Da higher than the calculated value (4627.08 Da). The plasma desorption mass spectrum of the synthetic peptide showed a protonated molecule at m/z 4624.1, which was 4 Da lower than the calculated one (4628.09 Da). The amino acid sequence of the peptide was confirmed in part by electrospray (ionspray) mass spectrometry using a high nozzle skimmer voltage difference. Five impurities were separated and identified by capillary electrophoresis/mass spectrometry and two of them also appeared in the plasma desorption mass spectrum.     

Trace elements determined along single strands of hair by inductively coupled plasma mass spectrometry

Flow injection-inductively coupled plasma mass spectrometry has been evaluated for determining the distribution profile of trace elements along a single strand of hair. Hair was cut into several mm long sections from follicle to the distal end. Each section was solubilized in a capped 1.5-mL polypropylene tube with small volume of nitric acid (typically 50 microL) at room temperature. After dilution an aliquot (50 microL) was introduced into the mass spectrometer by flow injection. The limit of determination was typically 5-50 pg with 5-10% precision (CV), depending on the element examined; this corresponds to sub-microgram/g concentrations of these elements in hair segments. Recent exposure and intake history of individuals to thallium or mercury could be reconstructed by this system.     

Direct analysis of protein mixtures by tandem mass spectrometry

Methods to identify proteins contained in mixtures are described. The approach uses microcolumn liquid chromatography and automated tandem mass spectrometry in conjunction with protein and nucleotide database searching algorithms. This approach is applied to the identification of proteins obtained by immunoprecipitation reactions, interaction with a GST protein fusion products and interaction with a macromolecular complex.     

Layerwise analysis of vacuum copper-chromium condensates by glow-discharge mass spectrometry

Features are examined of using high-sensitivity mass-spectral layerwise analysis in a glow discharge to examine Cu-Cr composite material made by electron-beam evaporation. A mathematical model is used to calculate the concentrations of molecular ions in the glow-discharge plasma in order to select isotopes free from molecular ions. The argon-ion etching allows one to examine the distributions of the main and impurity elements with a sensitivity of 10⁻⁵–10⁻⁶% with micrometer-scale spatial resolution. The distributions of Ti, Cr, Mn, Fe, Ni, Cu, and Ag in the layers have been examined to determine the effects of the trace impurities on the condensation of the atomic vapor. __________ Translated from Poroshkovaya Metallurgiya, Nos. 7–8(450), pp. 106–115, July–August, 2006.     

The efficacy of dequalinium chloride/benzalkonium chloride as well as medicinal plants on the gingiva

A comparative study involving 50 patients of both genders was conducted in order to determine the effect of dequalinium chloride/benzalconium chloride mouthrinse (Dequonal), and of a preparation of herbal essences (Parodontax) on gingival health. Each of the mouthrinses was used during four weeks by a group of 25 patients who were instructed to abstain from any other oral hygiene measure during this period. Approximal plaque index, sulcus bleeding index and saliva pH were significantly enhanced by both preparations. A slightly better effect shown by dequalinium chloride/benzalconium chloride was not significant.     

流动注射氢化物发生与动态反应池-电感耦合等离子体质谱法分析镍基超合金中锗砷硒

建立了流动注射(FI)氢化物发生(HG)与动态反应池(DRC)-电感耦合等离子体质谱法(CP-MS)分析镍基超合金样品中锗、砷、硒的方法。采用动态反应池-氢化物生成技术富集锗、砷、硒,选择半胱氨酸(L-Cys)以及使用气液分离装置,降低了Ni,Co基体在三种元素氢化物生成时的干扰。探讨了氢化物生成的最佳条件、气体流速及基质氧化物对测定的影响。结果表明,以2.0 g/L NaBH4作为氢气发生剂,20 g/L L-Cys作为掩蔽和增敏剂,控制气体流速为0.95 mL/min时,三种元素都有最佳的氢化物发生效     

Effect of intracolonic benzalkonium chloride on trinitrobenzene sulphonic acid-induced colitis in the rat

BACKGROUND: We investigated the effects of benzalkonium chloride (BAC) on trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. METHODS: TNBS was administered intrarectally before and/or after BAC treatment. In the first study, the effects of treatment with BAC 6, 12 or 24 h after TNBS were examined. In the second study, animals were treated with BAC before, after or before and after TNBS, and were examined 7 days later. The severity of colitis was assessed by macroscopic and histological scoring of the colonic damage and by determination of colonic myeloperoxidase (MPO) activity. Macrophages and CD4+ and CD8+ T cells were examined by immunohistochemistry. RESULTS: When BAC was instilled into the colon 6, 12 or 24 h after TNBS, weight loss and macroscopic and histological features of the colon were similar to that of controls (TNBS alone). In contrast, MPO activity was significantly reduced in all three groups post-treated with BAC. In the groups examined 7 days after TNBS treatment, rats post-treated with BAC exhibited increased weight gain and significantly reduced macroscopic damage and MPO activity compared to the TNBS control group. Rats pre-treated with BAC exhibited less macroscopic damage of the colon than rats receiving only TNBS, but histological damage, MPO and weight gain were unchanged from TNBS controls. Immunohistochemistry revealed that BAC pre-treatment increased the numbers of macrophages and T cells in the colon. After TNBS treatment, macrophage accumulation was evident in the colon, but T cells were scarce. However, these cells were preserved or enhanced in the colonic mucosa in TNBS-treated rats that had been pre-treated with BAC. CONCLUSIONS: Treatment with BAC, particularly after induction of colitis, produces a significant reduction in the severity of tissue injury and inflammation through mechanisms that are not fully understood.     

流动注射-氢化物发生-冷原子荧光光谱法测定土壤中痕量汞

采用小型一级气液分离器的二级气液分离的方法,流动注射-氢化物发生-冷原子荧光光谱法测定了土壤中的痕量汞.考察了反应管长度、载液酸度、载气流量等实验参数及共存元素对汞测定的影响.在优化的工作条件下,方法的检出限为0.7ng/L,精密度RSD(n=11)为2.7%.方法应用于土壤样品中痕量汞的分析,结果满意.     

流动注射-氢化物发生-原子吸收光谱法测定环境样品中砷的形态

基于在pH 5.6~6.0时,As(Ⅲ)能与硼氢化钾反应生成气态氢化物而As(Ⅴ)不发生反应,采用流动注射-氢化物发生-原子吸收光谱法(FIA-HG-AAS)联用技术并结合适宜的分离方法测定了当地环境水样中的总砷、有机砷、As(Ⅲ)及As(Ⅴ)的含量。对测定的有关条件,包括酸度、硼氢化钾的用量、预还原剂用量等进行详细的研究,建立了测定砷的最佳工作参数。方法的线性范围为0.088~10 ng/mL,回收率在92.5%~103.5%之间,RSD为0.94%。方法可用于环境水样中砷的形态分析。     

辉光放电质谱法分析颗粒状高纯铬的样品制备方案探讨

为了建立辉光放电质谱法(GD-MS)测定颗粒状高纯铬中痕量元素的方法,深入研究了颗粒状高纯铬样品的制备方案。比较了不同研磨方式和压片方案,考察了不同粒度、模具或压力下压制的高纯铬样品片中基体铬在不同放电参数下的信号强度。实验表明,当样品粒度为100目(150μm),采用铝杯模具在75t压力下压制时,样品成形效果较好,且对应基体铬信号强度与放电电压、放电气流和脉冲时间的线性关系较好,信号强度最高可达到5×10¹⁰ cps以上,较为理想;采用研磨仪自动研磨50~100g样品1min,100目(150μm)样品产率可达90%以上,因此采用此种方式处理样品。采用实验方法制备样品,用GD-MS分析颗粒状高纯铬中主要痕量元素的结果与电感耦合等离子体原子发射光谱法(ICP-AES)、电感耦合等离子体质谱法(ICP-MS)和原子吸收光谱法(AAS)测定值吻合较好,μg/g含量级别的钠、铝、硅、钙、钛、钒、锰、铁、镍、铜这10个杂质元素测定值的相对标准偏差(RSD,n=7)在0.80%~11.6%之间,ng/g含量级别的钼、锑、铅这3个杂质元素的RSD(n=7)则在3.7%~13.6%之间。方法为进一步研究颗粒状高纯铬样品全元素分析和纯度分析提供了可靠的试验方案。     

流动注射在线离子交换火焰原子吸收光谱法测定痕量银

用流动注射在线离子交换技术对Ag+进行在线富集,柠檬酸作掩蔽剂消除Fe3+,Al3+等离子的干扰,硝酸溶液作洗脱液,将Ag+从离子交换柱中洗脱,火焰原子吸收法测定,测定灵敏度可提高11倍。方法的测定范围为0.01～1.0μg/mL,进样频率为10样/h。方法用于自来水及井水中痕量银的测定,结果令人满意。     

流动注射离子交换分离-火焰原子吸收光谱法测定痕量铋

研究了采用流动注射技术进行痕量铋的离子交换分离富集 ,在 0 2mol/LHCl溶液中 ,Bi3 + 与Cl- 形成阴离子 ,被离子交换树脂交换富集 ,用 0.2mol/L硝酸 -1 2 %柠檬酸溶液洗脱 ,火焰原子吸收光谱法测定。经分离后 ,铋的测定灵敏度可提高数倍 ,大量共存离子不干扰铋的测定。方法用于钢铁及合金中微量铋的测定 ,结果令人满意。     

Distinguishing small molecular mass differences of proteins by mass spectrometry

This study was undertaken to determine if acidic or basic fibroblast growth factor (FGF1 or FGF2) or vascular endothelial growth factor (VEGF) alters the radiation response of small bowel after total-body irradiation (TBI). Female C3H mice were treated with various doses of angiogenic growth factor administered intravenously 24 h before or 1 h after TBI. Radiation doses ranged from 7 to 18 Gy. End points measured were the number of crypts in three portions of the small bowel, the frequency of apoptosis of crypt cells at various times after TBI, and the LD50/30 (bone marrow syndrome) and LD50/6 (GI syndrome). Fibroblast growth factors alone, without TBI, decreased the number of crypts per circumference significantly. Among the factors tested, FGF2 caused the greatest decline in baseline crypt number. Despite this decrease in the baseline crypt number, after irradiation the number of surviving crypts was greater in animals treated with growth factor. The greatest radioprotection occurred at intermediate doses of growth factor (6 to 18 pg/mouse). Mice treated with FGF1 and FGF2 had crypt survival curves with a slope that was more shallow than that for saline-treated animals, indicating radiation resistance of crypt stem cells in FGF-treated mice. The LD50/6 was increased by approximately 10% for all treatments with angiogenic growth factors, whether given before or after TBI. Apoptosis of crypt cells was maximum at 4 to 8 h after TBI. The cumulative apoptosis was decreased significantly in animals treated with angiogenic growth factors, and the greatest protection against apoptosis was seen in animals treated with FGF2 prior to TBI. All three angiogenic growth factors tested were radioprotective in small bowel whether given 24 h before or 1 h after irradiation. The mechanism of protection is unlikely to involve proliferation of crypt stem cells, but probably does involve prevention of radiation-induced apoptosis or enhanced repair of DNA damage of crypt cells.