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PubMed1990

[Microbiological assay method of BMY-28100 and some other cephem antibiotic in serum and tissues. Development of new sample preparation with Evan's blue, a high albumin binding dye].

With a new simple sample pretreatment, microbiological assay methods for quantitative determination of BMY-28100 and some other cephem antibiotics in serum and tissues have been developed. Presented sample pretreatment was founded on the extraction with Evans' blue, a high serum protein binding dye, and the ultrafiltration using cellulose membrane (Millipore; MW cutoff is 10,000) to which Evans' blue was specifically absorbed. Regardless of sample media, antibiotic contents in filtrates were determined accurately using calibration curves based on standard solutions prepared with 1/15 M phosphate buffer, pH 7.4. Four cephems, ceftriaxone (CTRX), cefazolin (CEZ), BMY-28100 and cefadroxil (CDX) were examined in human serum and rat liver tissues. Corrections were made for antibiotic recoveries into 1/15 M phosphate buffer, pH 7.4. CTRX, CEZ, BMY-28100 and CDX in serum and tissues were recovered into buffer at rates of 98.4-101.6%, 97.6-102.0%, 99.8-101.4% and 97.5-98.2% of of spiked (theoretical) values, respectively regardless of antibiotic concentrations. Furthermore, these concentrations obtained using the present bioassay method were well in agreement with those obtained by the HPLC method. When BMY-28100 was administered to volunteers, concentrations of BMY-28100 in serum obtained by the present bioassay method were well in agreement with those obtained by the usual bioassay method which required the fresh human serum to prepare the standard solutions.

Animals↗
PubMed2004

Simplified sample preparation using frame spotting method for direct counting of total bacteria by fluorescence microscopy.

A new preparation method for direct counting of bacteria in liquid samples with fluorescence microscope was developed using a glass slide coated with 3-aminopropyltriethoxy silane and ring-shaped polyester seal as a retainer. The experimental steps of this method were spotting samples onto the coated slides with the seal, drying under vacuum, staining with SYBR Green II, drying and covering with immersion oil and coverslip to allow counting. This simplified method provided consistent results when compared with the conventional filtration method for fluorescence microscopy, and is rapid, inexpensive and reproducible.

Bacteriological Techniques↗
PubMed2003

Effects of sampling, preparation and defecation on metal concentrations in selected invertebrates at urban sites.

In order to obtain basic information for designing standardized test preparation methods, the heavy metals Zn, Cu, Cd and Pb were measured in gastropods (Xerolenta obvia), oligochaetes (Lumbricus terrestris), isopods (Armadillidium vulgare, Trachelipus rathkei) and carabids (Harpalus rubripes, Calathus fuscipes) using different sampling methods and different modes of sample treatment. In some of the experiments, higher Zn, Cd and Pb, and lower Cu-contents were observed in isopods and carabids trapped with formalin-pitfalls compared to manually collected specimens (which were allowed to defecate). Defecation had marked effects on the levels of all four metals investigated in oligochaetes, and on Cd and Pb in gastropods and isopods. Cellulose was fed as an accelerator of gut passage and showed a significant effect on the Pb concentration in the soft body of gastropods. Deionate-washed isopods (A. vulgare) showed higher Cd concentrations than ultrasonic-cleaned individuals. No marked differences were observed between heat-dried and freeze-dried isopods. Carabids showed strong sex-specific differences in metal concentrations. Based on these and previous results, invertebrates should be: collected in vivo, allowed to defecate, be freeze-fixed and (at least in arthropods) ultrasonic-cleaned, determined to species level and in certain groups (carabids) also to sex, and then be sized or sorted by size (age) before further preparation and analysis. If any of these treatments is impractical, comparable sampling and preparation methods are recommended as a minimum requirement in order to avoid bias in the results and/or interpretation.

Animals↗
PubMed2006

Ultrasound-assisted digestion: a useful alternative in sample preparation.

Ultrasound-assisted digestion is a promising alternative in the analysis of solid samples when either simple dissolution or direct analysis is not applicable. However, the field of application of ultrasonic sample digestion is still small in comparison with classical digestion alternatives and, particularly, with microwave-assisted digestion. This fact can be justified by the scant knowledge analytical chemists have about the advantages ultrasonic energy provides to digestion. Among these, the strict control at low temperatures of ultrasound applications allows the implementation of ultrasonic-assisted steps in biochemical analyses. In this connection, two specific biological applications, ultrasonic enzymatic digestion and assistance of ultrasound for cell disruption, are also reviewed.

Cell Fractionation↗
PubMed2004

Automated multi-dimensional liquid chromatography: sample preparation and identification of peptides from human blood filtrate.

A comprehensive on-line sample clean-up with an integrated two-dimensional HPLC system was developed for the analysis of natural peptides. Samples comprised of endogenous peptides with molecular weights up to 20 kDa were generated from human hemofiltrate (HF) obtained from patients with chronic renal failure. The (poly-)peptides were separated using novel silica-based restricted access materials with strong cation-exchange functionalities (SCX-RAM). The size-selective sample fractionation step is followed by cation-exchange chromatography as the first dimension. The subsequent second dimension of separation is based on hydrophobic interaction using four parallel short reversed-phase (RP) columns implemented via a fully automated column switching technique. More than 1000 peaks were resolved within the total analysis time of 96 min. Substances of selected peaks were sampled to analyse their molecular weights by off-line MALDI-TOF mass spectrometry and to determine their amino acid sequence by Edman degradation. The potential for comprehensive peptide mapping and identification is demonstrated.

Amino Acid Sequence↗
PubMed1983

Sample preparation by salts precipitation and quantitation by high-performance liquid chromatography with UV detection of selected drugs in biological fluids.

A quantitative clean-up procedure for drugs in plasma and urine in preparation for high-performance liquid chromatographic analysis is discussed. Samples are mixed with zinc sulfate, barium hydroxide, and acetonitrile (or methanol). Resultant solutions are clear and free of visible residue. Injections of over 420 samples of treated urine and 120 samples of treated plasma had no noticeable effect on pressure drop and column performance. An examination of the column head indicated no damage or discoloration to the packing. Baselines of the controls show no interference from endogenous compounds for the drugs studied. Precision study using cyclobenzeprine . HCl in plasma and urine by internal standard and external standard methods has within-run and day-to-day variations of under 5%. Drugs studied in urine and plasma are amiloride . HCl, cyclobenzeprine . HCl, cyproheptadine . HCl, diflunisal, indomethacin, phenylbutazone and sulindac. These drugs are selected for the various functional groups, their binding by proteins and their natural UV absorptivity. Conditions to improve recovery, advantages and limitations are discussed.

Chemical Precipitation↗
PubMed1998

Comparison of sample preparation methods for detection of Legionella pneumophila in culture-positive bronchoalveolar lavage fluids by PCR.

A prospective study was conducted on 25 Legionella pneumophila culture-positive and 98 culture-negative bronchoalveolar lavage fluid samples to compare two DNA preparation methods: a rapid modified Chelex-based protocol and a proteinase K method. PCR was found to be more sensitive with the Chelex-based method (P = 0.03). N difference was found concerning the inhibition rate.

Bacteriological Techniques↗
PubMed1997

The use of supercritical fluid extraction for sample preparation of pharmaceutical formulations.

This paper reviews the use of supercritical fluid extraction (SFE) as a sample work-up step in the analysis of drugs in various pharmaceutical formulations. Matrices studies include tablets, animal feed, creams, ointments and infusions. As in other fields of analytical chemistry, SFE has proven to be most suitable for comparatively non-polar compounds in solid matrices. Examples are given however where SFE can also be used, with success, for polar substances or for target compounds present in infusions or other water-based samples. The premise of inverse SFE, i.e. extraction of the matrix instead of the target compound, is discussed.

Animal Feed↗
PubMed1999

Sample preparation and storage can change arsenic speciation in human urine.

BACKGROUND: Stability of chemical speciation during sample handling and storage is a prerequisite to obtaining reliable results of trace element speciation analysis. There is no comprehensive information on the stability of common arsenic species, such as inorganic arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid, dimethylarsinic acid, and arsenobetaine, in human urine. METHODS: We compared the effects of the following storage conditions on the stability of these arsenic species: temperature (25, 4, and -20 degrees C), storage time (1, 2, 4, and 8 months), and the use of additives (HCl, sodium azide, benzoic acid, benzyltrimethylammonium chloride, and cetylpyridinium chloride). HPLC with both inductively coupled plasma mass spectrometry and hydride generation atomic fluorescence detection techniques were used for the speciation of arsenic. RESULTS: We found that all five of the arsenic species were stable for up to 2 months when urine samples were stored at 4 and -20 degrees C without any additives. For longer period of storage (4 and 8 months), the stability of arsenic species was dependent on urine matrices. Whereas the arsenic speciation in some urine samples was stable for the entire 8 months at both 4 and -20 degrees C, other urine samples stored under identical conditions showed substantial changes in the concentration of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid. The use of additives did not improve the stability of arsenic speciation in urine. The addition of 0.1 mol/L HCl (final concentration) to urine samples produced relative changes in inorganic As(III) and As(V) concentrations. CONCLUSIONS: Low temperature (4 and -20 degrees C) conditions are suitable for the storage of urine samples for up to 2 months. Untreated samples maintain their concentration of arsenic species, and additives have no particular benefit. Strong acidification is not appropriate for speciation analysis.

Arsenicals↗
PubMedDate not supplied

Comparison between flow cytometric and cytogenetic tumor cell DNA content using a simple flow sample preparation method: ploidy comparison of 86 fresh pediatric tumors.

A comparison of tumor ploidy by flow cytometry (FL) and cytogenetics (CYG) was made in 86 fresh pediatric solid (n = 47) and hematopoietic (n = 39) tumors using simple sampling and semiautomated proprietary FL preparation methods and defined histogram interpretive criteria. Tumor karyotypes with 44-48 chromosomes were regarded as CYG diploid and other chromosomal complements CYG aneuploid for comparison purposes. Five histograms were uninterpretable and nine cases failed to produce 15 or more metaphases for karyotyping. Mean G0/G1 peak coefficients of variation of all 86 cases were 2.7 and 3.0 for the diploid and aneuploid populations, respectively. Of the 72 eligible cases, 41 were concordant diploid and 16 concordant aneuploid with an overall concordance of 79%. The DNA index and karyotypic index correlation coefficient was 0.92 for the 16 concordant aneuploid cases. Analysis of the 15 discordant cases highlights the limitations of both methods and of the histogram interpretive criteria and indicates that FL is probably more sensitive for detection of tumor aneuploidy as defined and detected by these methods.

Aneuploidy↗
PubMed2000

The determination of carbonyl compounds in air using a robotic sampling preparation system integrated to a gas chromatograph with a nitrogen-phosphorus detector.

A totally automated solid phase extraction gas chromatography procedure was developed for the sampling and analysis of carbonyl compounds in air. In this system, two PrepStation modules were used, one for the preparation and elution of 2,4-dinitrophenylhydrazine silica cartridges, and the other for air sampling. The sample collected by the sampling module was eluted to an autosampler vial in the PrepStation module and then transferred to the gas chromatograph for analysis via a robotic arm. The sampling module was modified to enable air sampling via an external pump. A typical run by this technique required 142 min, 100 min for air sampling and 42 min for the other operations, including a GC analysis time of 25 min. Recoveries of at least 85% were obtained for all compounds studied. The detection limits for formaldehyde, acetaldehyde and acetone were 2.2, 2.7 and 2.2 ppbv, respectively. All operations, including the conditioning of the cartridges, were performed without any intervention from the analyst.

Air Pollutants↗
PubMed1999

Determination of ifosfamide by HPLC using on-line sample preparation.

The Authors have developed a novel and easily applicable HPLC method for ifosfamide (IF) determination. This method involves on-line sample processing and its solid-phase extraction by means of an automatic preparator integrated with the chromatographic system. The calibration graph of the method is linear in the concentration range 6-200 microg/ml; minimum detectable concentration is 6 microg/ml. This highly accurate and easily reproducible method was used by the Authors in the treatment of osteosarcoma with slow infusion of ifosfamide.

Adolescent↗
PubMed1992

Solid-phase extraction of prostanoids using an automatic sample preparation system.

A commercial automated solid-phase extraction system for cyclooxygenase arachidonic acid metabolites in urine samples has been evaluated. Comparison of manual and automatic batch (36 samples) extraction procedures for tritium labelled prostanoids added as tracers to urine samples has shown equivalent results with recoveries greater than 90% for prostaglandins E2, F2alpha and 6-keto prostaglandin F1alpha as well as thromboxane B2. Analyte stability is not affected by the automated procedure, which uses less solvents and has a faster overall processing time than the manual method. The automated system has been applied to the extraction of prostanoids in urine samples from workers exposed to dichloroethane.

Arachidonic Acids↗
PubMed1999

Liquid-liquid-liquid microextraction for sample preparation of biological fluids prior to capillary electrophoresis.

Methamphetamine as a model compound was extracted from 2.5-mL aqueous samples adjusted to pH 13 (donor solution) through a thin phase of 1-octanol inside the pores of a polypropylene hollow fiber and finally into a 25-microL acidic acceptor solution inside the hollow fiber. Following this liquid-liquid-liquid microextraction (LLLME), the acceptor solutions were analyzed by capillary zone electrophoresis (CE). Extractions were performed in simple disposable devices each consisting of a conventional 4-mL sample vial, two needles for introduction and collection of the acceptor solution, and a 8-cm piece of a porous polypropylene hollow fiber. From 5 to 20 different samples were extracted in parallel for 45 min, providing a high sample capacity. Methamphetamine was preconcentrated by a factor of 75 from aqueous standard solutions, human urine, and human plasma utilizing 10(-1) M HCl as the acceptor phase and 10(-1) M NaOH in the donor solution. In addition to preconcentration, LLLME also served as a technique for sample cleanup since large molecules, acidic compounds, and neutral components were not extracted into the acceptor phase. Utilizing diphenhydramine hydrochloride as internal standard, repetitive extractions varied less than 5.2% RSD (n = 6), while the calibration curve for methamphetamine was linear within the range 20 ng/microL to 10 micrograms/mL (r = 0.9983). The detection limit of methamphetamine utilizing LLLME/CE was 5 ng/mL (S/N = 3) in both human urine and plasma.

Diphenhydramine↗
PubMed1988

Indirect immunofluorescent test on spore sampling preparations: a technique for diagnosis of individual mold allergies.

To calculate their respective exposure to mold spores, volumetric spore sampling was performed with Burkard personal air samplers in the homes of six asthmatic patients with different mold allergies, of three patients with baker's asthma and of four healthy controls. The spore samples were investigated with an indirect immunofluorescent test. Spore-specific IgE was detected in the serum of all the asthmatic patients with mold allergies, even in patients with only slightly increased or no detectable specific IgE in Phadezym-RAST. In serum of patients with baker's asthma and healthy controls, no spore-specific IgE was found.

Antibodies, Fungal↗
PubMed2000

Liquid chromatography/electrospray tandem mass spectrometry method for the quantitation of fosinoprilat in human serum using automated 96-well solid-phase extraction for sample preparation.

A sensitive, specific, accurate and reproducible liquid chromatography/electrospray tandem mass spectrometry method was developed and validated for the quantitation of fosinoprilat in 0.2 mL of human serum. The method employed acidification (with pH 4.0 sodium acetate buffer) of the serum samples to minimize the hydrolysis of the prodrug fosinopril to fosinoprilat prior to purification by automated 96-well solid-phase extraction. The required chromatographic separation of fosinoprilat and fosinopril was achieved isocratically on a Luna C8 analytical column (2 x 50 mm, 3 microm). The total run time was 2 min. The mobile phase contained methanol and water with 10 mM ammonium acetate. Detection was by positive ion electrospray tandem mass spectrometry. The standard curve, which ranged from 2.00 to 500 ng/mL, was fitted to a 1/x(2) weighted linear regression model. Fosinoprilat quality control (QC) samples used to determine the accuracy and precision of the method were prepared in human serum at concentrations of 5.00, 200, 400 and 1000 ng/mL. The assay accuracy was within 8% (dev). The intra- and inter-assay precisions were within 6 and 3% (RSD), respectively. Fosinopril QC samples used to gauge the rate of hydrolysis of fosinopril to fosinoprilat during the assay procedure were prepared in human serum at 500 ng/mL. The hydrolysis of fosinopril to fosinoprilat was </=1%. This degree of conversion would cause little error in the analysis of post-dose serum samples since such samples are known to contain low levels of the prodrug compared with the drug.

Analysis of Variance↗
PubMed2004

Influence of the sample preparation method on the serotonin determination in plasma and platelets.

Plasma or platelet serotonin concentration is commonly used to provide information about the serotonergic activity in various psychiatric or neurological diseases. Some difficulties have been described in the measurement of serotonin (5-HT) levels in plasma or platelets. We describe an isocratic liquid-chromatographic assay with amperometric detection for determination of 5-HT in the platelet pellet and in platelet-rich and platelet-poor plasma (PRP and PPP) in sample sizes of 100 microL of plasma. The method uses an RP(18) column and an amperometric detector with a thin-layer type electrochemical fl ow cell, with glassy carbon electrode maintained at a potential of +0.600 V vs an Ag/AgCl reference electrode. Determinations were performed in the presence or in the absence of plasma, since the biological matrix may affect the results. Different validation parameters were analysed: selectivity, accuracy, precision, linearity and stability. Reference values for 5-HT concentration in healthy adults (n = 12) were 6.6 nmol/10(9) platelets, for the platelet pellet, and 5.5 nmol/10(9) platelets, for PRP. The 100 microL sample volume used for the preparation of PPP did not make possible the determination of 5-HT levels with accuracy and precision.

Adult↗