Sep-Pak Plus Research Articles

Biological Method for Residual Tetracyclines in Propolis

A biological method for residual tetracyclines (TCs) in propolis was evaluated. Oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) were extracted from a sample with 5% citric acid containing 0.001M EDTA-2Na. The extract was washed with hexane and diethyl ether, followed by a Sep-pak Plus PS2 cartridge clean-up and TCs adsorbed in the cartridge were eluted with methanol. The eluate was concentrated to dryness, and the residue was redissolved in a phosphate buffer (pH 4.5) and treated with polyamide resin to remove antibacterial substances originating from propolis. The cup-plate method was employed for quantitative determination, and microbioautography for identification of TCs. The recoveries were 97.6% (OTC), 92.7% (TC) and 86.3% (CTC), and the detection limits were 0.1μg/g (OTC, TC) and 0.02μg/g (CTC).

Determination of Nitrophenol Pesticides in Mineral Water and Tap Water by HPLC with Ultraviolet and Amperometric Detection

A simultaneous analytical method was developed for 9 nitrophenol pesticides and 2 aromatic nitro pesticides in drinking water by HPLC. The analytical HPLC was run on a Wakosil II 3C18AR column (4.6mm i. d. ×15cm) with a gradient formed from A: 0.1M monochloroacetic acid (pH 2.5)-MeCN-0.01M sodium butanesulfonic acid (10:30:60) and B: 0.1M monochloroacetic acid (pH 2.5)-MeCN (10:90), UV detection at 280nm and amperometric detection (AMD) with a glassy-carbon electrode (+1.2V). A drinking water sample was adjusted to pH 4 with 0.1M hydrochloric acid and purified on a Sep-pak Plus PS-2 cartridge. The cartridge was washed with water, and retained substances were eluted with MeCN. The eluate was concentrated under an N2 stream and was analyzed by HPLC. Recoveries for pesticides spiked into drinking water were 58.0-98.6% at the level of 20μg/L. The detection limits of these pesticides in water are 1μg/l.

Preparation of Sample Solution Using Pronase Treatment for Determination of Food Coal-Tar Dyes in Foods

A method for preparation of sample solutions has been developed for determination of food coal-tar dyes in foods by using pronase. Twelve kinds of dyes were extracted with a mixture of 1% NH4OH and ethanol from foods which were hydrolyzed by pronase treatment. Then the extract was concentrated under vacuum, cooled in ice, treated with tetrabutylammonium hydroxide and cleaned up by using Sep-pak Plus tC18 cartridges. The dyes retained on the replaced cartridge were eluted with a mixture of methanol and tetrabutylammonium phosphate solution (pH 5.0), and determined by gradient high performance liquid chromatography with visible wavelength detectors.The recoveries of food coal-tar dyes were more than 76.0% from foods spiked at 1 and 10μg/g levels.

Simultaneous determination of deflazacort metabolites II and III, cortisol, cortisone, prednisolone and prednisone in human serum by reversed-phase high-performance liquid chromatography.

A new high-performance liquid chromatographic method for the analysis of human serum from subjects administered prednisolone or deflazacort has been established. Two deflazacort metabolites (metabolites II and III), prednisolone and its metabolite (prednisone), as well as cortisol and cortisone in human serum were analyzed simultaneously. These six compounds and the internal standard, betamethasone, were extracted from 1 ml of human serum using a Sep-Pak Plus Environmental C18 column and then separated on a Hypersil ODS (25 x 0.46 cm I.D.) column using a gradient system. The lower limit of quantitation for each compound was 10 ng/ml based on signal-to-noise ratio of 5 and calibration curve linearity. Within-day and between-day validations gave a coefficient of variation of less than 10% and a relative error of ca. 10% (n = 11).

水道水のＡｍｅｓ変異原性に関する研究 第２報 高性能吸着剤を用いた変異原性物質の濃縮・回収方法

Sample preparation method using a cartridge (Sep-Pak Plus Long) in which 2ml of a superior adsorbent CSP800 was packed was optimized for convenient and quantitative Ames mutagenicity assay of tap water.Mutagenicity activities were decreased considerably by free chlorine reduction by sodium sulfite. Recovery of mutagens from tap water augmented much in lower pH. There was no influence of adsorbing flowrate in the range from 8 to 80ml·min-1 on the recovery of mutagens. Therefore, it is optimal that tap water adjusted at pH2 without free chlorine reduction is fed to the cartridge at a flowrate of c.a. 50ml·min-1. By this method, the mutagens less than 8,000 net revertants.·l-1 could be recovered completely from 2l of water sample, and those more than that could be recovered from 1l. The adsorbed mutagens could be desorbed by 2ml-dimethyl sulfoxide (DMSO) at 0.15 ml·min-1 in upper flow.This newly developed method requires only 1 or 2l of water sample and less than an hour to concentrate mutagens with over 90% recovery. Furthermore, the desorbing DMSO solution can be used directly to Ames assay without solvent exchange, because concentration factor of mutagens by this method attains 500 or 1,000 times.

水道水のＡｍｅｓ変異原性に関する研究 第１報 変異原性物質濃縮回収用の吸着剤

A new superior adsorbent was selected for a convenient and quantitative mutagenicity assay of tap water. Adsorption abilities of various adsorbents such as CSP800, XAD4, XAD4/8, blue rayon, and blue cotton were investigated for recovering mutagens from tap water. CSP800 and XAD4 are highly porous polystyrene resins, but CSP800 has larger surface area and smaller particle size than XAD4. XAD4/8 is a mixture of a XAD4 and XAD8 of porous polyacrylate. Blue rayon and blue cotton are cellulose bonded copper phthalocyanine trisulfonate.It was confirmed clearly that a new adsorbent CSP800 could recover much more mutagens in a short time than the others. Then convenient refining and conditioning method of the CSP800 was defined as follows ; Five cartridges packed 2ml of CSP800 (Sep-Pak Plus Long) were connected in series, and washed by 400ml of ethyl acetate, 200ml of ethanol, and 100ml of pure water by turns at 10ml·min-1. After this refining and conditioning method, any mutagens did not elute from the adsorbent, and a little remained ethanol did not disturb the adsorption of mutagens from tap water.