In this study the temperature stability of several normal phase and RP columns was investigated using a water‐only mobile phase. The temperature was adjusted to 120°C for the bare silica stationary ...phases and to 185°C for the metal oxide and carbon stationary phases. It could be shown that metal oxide stationary phases exhibited excellent thermal stability over the duration of the test period and are therefore suitable for high temperature LC applications.
The ‘EstraMonitor’ was developed to provide an automated system for the detection of estrogenic compounds. It can be used for semi-online and continuous monitoring without additional instrumentation. ...Previously it was used to detect pure estrogenic molecules. In this investigation, the ‘EstraMonitor’ is used to detect the estrogenic activity in five non-pretreated wastewater samples. The ‘EstraMonitor’ employs genetically modified Arxula adeninivorans G1212/YRC102-hERα-phyK yeast cells as the detection component. Both immobilized and non-immobilized A. adeninivorans G1212/YRC102-hERα-phyK cells remained fully functional in a wide range of samples, including samples that contained up to 5% NaCl. The results demonstrate that it is possible to determine the estrogenic effects in environmental samples without the need for sterilization, extraction or concentration. The 17β-estradiol equivalent quotient (bio-EEQ) values in these samples were measured by both biochemical and amperometric methods and were compared to GC–MS analyses (ana-EEQ). The three methods showed a good correlation over a similar detection range.
The two Arxula adeninivorans-based bioassays (A-YGS and A-YGFS) described here provide sensitive and reliable screening for glucocorticoids in aquatic environments. The biocomponents of A-YGS and ...A-YGFS were constructed to carry the human glucocorticoid receptor (hGRα) and the phytase gene (phyK, derived from Klebsiella sp. ASR1) or a fluorescence dsRED gene (derived from the Discosoma sp.), as reporter genes. The responses of A-YGS and A-YGFS were measured photometrically and spectrofluorometrically respectively. The half effective concentration (EC50) and limit of detection (LoD) values for dexamethasone obtained with A-YGS and A-YGFS were 0.81 and 0.29μM, and 9.42 and 0.47μM, respectively. Furthermore, both bioassays exhibited different binding specificities for several natural and synthetic glucocorticoids: A-YGS – corticosterone>cyproterone acetate>mifepristone>dexamethasone>cortisol>methylprednisolone>prednisolone and A-YGFS – cortisol>corticosterone>dexamethasone>prednisolone>betamethasone>methylprednisolone.
As proof of principle, A-YGS was used to assay total glucocorticoids in river water, wastewater influent and effluent taken from a wastewater treatment plant in Germany. Glucocorticoids were not detected in both A-YGS and LC–MS/MS in seven of the eight samples, however a dexamethasone equivalent (DEQ) was detected in an influent wastewater sample using A-YGS (0.055μM), while LC–MS/MS analysis showed that hydrocortisone and cortisone were present at 0.063 and 0.083nM, respectively.
A fast HPLC method for the analysis of eight selected sulfonamides (SA) and trimethoprim has been developed with the use of high temperature HPLC. The separation could be achieved in less than 1.5 ...min on a 50 mm sub 2 μm column with simultaneous solvent and temperature gradient programming. Due to the lower viscosity of the mobile phase and the increased mass transfer at higher temperatures, the separation could be performed on a conventional HPLC system obtaining peak widths at half height between 0.6 and 1.3 s.
The aims of the study were to quantify levels of dermal and inhalation exposure to antineoplastic drugs in an industrial laundry service in the Netherlands and to test the removal efficiency of the ...washing procedure for removal of antineoplastic drugs.
During four workdays dermal and inhalation exposure to eight frequently used antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, 5-fluorouracil, etoposide, cytarabine, gemcitabine and chlorambucil) were measured for all job titles involved in handling unwashed laundry. To test the removal efficiency of the washing procedure, 10 x 10 cm sections were excised before and after the washing procedure. These sections were taken from 15 bed sheets that were collected in hospitals of patients who were treated with one of the selected antineoplastic drugs.
During none of the four measurement days, detectable levels of any of the eight antineoplastic drugs (cyclophosphamide, ifosfamide, methotrexate, 5-fluorouracil, etoposide, cytarabine, gemcitabine, or chlorambucil) were found on workers' skin of hands or in any of the air samples. Only four out of the 15 bed sheets from patients that were treated with antineoplastic drugs appeared to be contaminated with detectable levels of antineoplastic drugs before the washing procedure (range 13.0-3,060 ng/100 cm(2)). After the pre-washing and after the complete washing procedure, no detectable levels of any of the eight antineoplastic drugs were found anymore in the selected bed sheets.
The implementation of guidelines for working with antineoplastic drugs seems to be successful in reducing exposure to antineoplastic drugs of workers in this laundry facility to an acceptable, non-detectable level and to remove antineoplastic drug contamination from bed linen.
Two major metabolites and one minor metabolite of sulfadiazine were found in pig manure, using a special combination of different MS techniques like parent and product ion scans, H/D exchange, ...accurate mass measurement, and MS/MS experiments with substructures. N4-acetylsulfadiazine and 4-hydroxysulfadiazine were identified as major metabolites. N4-acetylsulfadiazine could be verified by H/D exchange and comparison with product ion spectra of a synthetic reference compound. In the case of 4-hydroxysulfadiazine, the majority of possible isomers could be discounted after H/D exchange. Substructure-specific MS/MS experiments with fragment ions and comparison with product ion spectra of two references revealed the presence of 4-hydroxysulfadiazine. The minor metabolite was characterized to some degree using H/D exchange and tandem mass spectrometry in combination with a high-resolution time of flight mass spectrometer. The aminopyrimidine moiety contained an additional modification with a likely elemental composition of C
2H
4O and no further acidic hydrogen.
In this paper, three different HPLC methods for the quantification of thalidomide in tablets were developed and compared. The comparison of a conventional method at 30
°C with two high-temperature ...methods at 180
°C showed equal results. Using high-temperature HPLC (HT-HPLC), faster analysis times could be achieved. We have also focused on analyte stability and could show that the stationary phase has a pronounced effect on the on-column degradation of thalidomide at high temperatures. Virtually no degradation occurs if a polystyrene divinylbenzene column is used, whereas thalidomide is completely degraded at 180
°C when a carbon clad zirconium dioxide column is used.
Ozonation of diclofenac in aqueous solution in the presence and absence of an ...OH scavenger, tertiary butanol (t-BuOH), was studied, and the most important reaction intermediates and products were ...identified. The second-order O... rate constant was determined by competition with buten-3-ol and was found to be 6.8 x 10... M... s... at 20 ...C. From this high rate constant, it has been concluded that O... must initially add on the amino nitrogen. Decomposition of the adduct results in the formation of O... (...OH) and aminyl radical precursors. A free ...OH yield of 30% was estimated based on the HCHO yields generated upon reaction of ...OH with 0.01 M t-BuOH. Almost all diclofenac reacted when the molar ratio of O.../diclofenac was ~5:1 in the presence of t-BuOH and ~8:1 in its absence. As primary reaction products (maximum yield), diclofenac-2,5-iminoquinone (32%), 5-hydroxydiclofenac (7%), and 2,6-dichloroaniline (19%) were detected with respect to reacted diclofenac in the presence of t-BuOH. These primary products degraded into secondary ones when the O... dose was increased. In the ...OH-mediated reaction (absence of t-BuOH) small yields of 5-hydroxydiclofenac (4.5%), diclofenac-2,5-iminoquinone (2.7%), and 2,6-dichloroaniline (6%) resulted. Practically all Cl... (95%) was released in the absence of t-BuOH but only about 45% in the presence of t-BuOH at an O.../diclofenac molar ratio of 10:1. Based on the reaction products, mechanisms that may account for the high O... consumption during ozonation of diclofenac are suggested. For technical applications, adequate supply of O... is needed not only to eliminate diclofenac, but also for the degradation of its potentially toxic products like diclofenac-2,5-iminoquinone and 5-hydroxydiclofenac. (ProQuest: ... denotes formulae/symbols omitted.)
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