Bank of reference samples of blank urine from livestock

From three species of livestock, bovine, ovine and porcine, samples of urine from each 10–20 different animals were collected. The animals originated from a governmental experimental farm and differed in race, age, sex and were fed with different types of feed. Fifty different samples of urine were lyophilised in units of 5 mL in sealed amber glass bottles. After lyophilisation of the samples, several quality control tests were performed. The variation in net weight of the units of urine and the lyophilisates ranged from 0.01%–1.7% and 0.1%–10%, respectively. Most values did not exceed 0.1% for urines and 1% for lyophilisates. The residual water content of the lyophilisates was determined by the Karl-Fisher titration method. The average percentage of residual water ranged from 1.0%–7.0% for bovine, from 1.3%–3.0% for porcine and from 1.6%–5.5% for ovine urine lyophilisates. Further, all different samples were analysed for the presence of anabolic compounds with a multi-residue procedure developed at the CRL. In two samples of bovine urine the presence of α-boldenone was detected and confirmed. In most porcine urines the endogenous steroids α-testosterone and α-estradiol were detected. In a number of porcine and ovine urine samples α- and β-zearalenol were detected. The origin of these compounds is the f2-toxin produced by a Fusarium fungus. In ovine samples α-testosterone and α-estradiol were detected.     

Effects of chromatography conditions on intact protein separations for top-down proteomics

A chiral stationary phase (CSP) has been prepared by chemically bonding a chiral pseudo-18-crown-6 type host having a 1-phenyl-1,2-cyclohexanediol unit to 3-aminopropyl silica gel. The chiral column was prepared by the slurry-packing method in a stainless steel HPLC column. Normal mobile phases can be used with this CSP in contrast to conventional dynamic coating type CSPs. Enantiomers of 20 out of 30 amino compounds, including 20 amino acids, 2 amino acid methyl esters, 6 amino alcohols, and 2 lipophilic amines, were efficiently separated on columns with this CSP. It is noteworthy that 15 amino compounds out of 30 were separated with better separation factors and shorter retention times compared to the corresponding CSP having pseudo-18-crown-6 with 1-phenyl-1,2-ethanediol as a chiral unit. In view of the correlation between the enantiomer selectivities observed in chromatography and those obtained in gas phase FABMS-EL methods and solution phase titrations, chiral recognition in the host-guest interaction likely contributes to enantiomer separation.     

Nitrofuran antibiotic residues in pork: The FoodBRAND retail survey

Use of nitrofuran drugs in food-producing animals has been prohibited within the EU because they may represent a public health risk. Monitoring compliance with the ban has focused on the detection of protein-bound nitrofuran metabolites which, in contrast to the parent compounds, are stable and persist in animal tissues. As part of the “FoodBRAND” project, an extensive survey of pork was undertaken across 15 European countries. Samples (n = 1500) purchased at retail outlets were analysed for the nitrofuran metabolites AOZ, AMOZ, AHD and SEM using LC–MS/MS determination of nitrobenzaldehyde derivatives. Limits of quantification for the method were 0.1 μg/kg (AOZ, AMOZ), 0.2 μg/kg (SEM) and 0.5 μg/kg (AHD). Of the 1500 samples tested, measurable residues of nitrofuran metabolites were confirmed in 12 samples (0.8% incidence overall) of which 10 samples were purchased in Portugal (AOZ, 0.3 μg/kg; AMOZ, 0.2–0.6 μg/kg) and one sample each in Italy (AMOZ, 1.0 μg/kg) and Greece (AOZ, 3.0 μg/kg).     

Localization of tetra(m-hydroxyphenyl)chlorin (Foscan) in human healthy tissues and squamous cell carcinomas of the upper aero-digestive tract, the esophagus and the bronchi: a fluorescence microscopy study

To date, little is known about precise time-dependent distribution and histological localization of tetra(m-hydroxyphenyl)chlorin (mTHPC) in human healthy tissues and squamous cell malignancies in the upper aero-digestive tract. A fluorescence microscopy study was performed on 50 healthy tissue biopsies and on 13 tumors (graded from Tis to T1 SCC) from 30 patients. Tissue samples were taken between 4 h and 11 days following injection of 0.15 mg/kg mTHPC. A fairly comparable distribution pattern in various tissues was observed over time in different patients. Vascular localization of mTHPC fluorescence predominates at a short delay, whereas the dye is essentially located in the tumoral and healthy mucosa after longer delays. A much lower uptake and retention of mTHPC fluorescence was noted in striated muscle and cartilage as compared to neoplastic lesions. No significant selectivity was found between healthy and tumoral mucosa. The obtained data are important to confirm drug-light interval that have been selected for effective PDT for early SCC malignancies while minimizing the risks of over- or under-treatment. The low fluorescence level in striated muscle provides the opportunity to develop interstitial PDT as a treatment modality for invasive SCC of unfavorable locations in the oral cavity or pharynx, such as the base of the tongue.     

Contribution to the study of the mechanism of curing of unsaturated polyester resins

The mechanism of copolymerization of monomethyl and dimethyl maleates and fumarates with styrene was studied by analysis of the conformation of the acid units of the resulting copolymers. The absorption bands for C?O stretching and OH stretching in the spectra of the copolymers are fully identical. They are quite different from the spectra of the copolymers obtained from maleic anhydride and styrene that are subsequently treated with absolute methanol to give the monoester which is then esterified with diazomethane to give the diester. The acid units of the copolymers derived from maleic anhydride exist in a gauche configuration; copolymers derived from fumaric units exist in a trans conformation. The identity of copolymers derived from maleic units with those derived from fumaric units but not with those derived from maleic anhydride indicates that the first step in the copolymerization of the maleic units is an isomerization to fumaric units, which are actually the genuine comonomers.     

A novel solid support for the synthesis of 3-aminoalkylated oligonucleotides

A novel improved controlled pore glass (CPG) support based on the 2-(hydroxymethyl)-6-nitrobenzoyl (HMNB) protecting group was developed for the synthesis of 3^′-aminoalkylated oligonucleotides. The release of oligonucleotides with free 3^′-amino groups from the support is complete within 2 h at 55 °C in concentrated ammonia.     

Vacancy ion-exclusion chromatography of aromatic carboxylic acids on a weakly acidic cation-exchange resin

Determination of aromatic carboxylic acids by conventional ion-exclusion chromatography is relatively difficult and methods generally rely on hydrophobic interaction between the solute and the resin. To overcome the difficulties in determining aromatic carboxylic acids a new approach is presented, termed vacancy ion-exclusion chromatography, which is based on use of the sample as mobile phase and an injection of aqueous 10% methanol onto a weakly acidic cation-exchange column (TSKgel OApak-A). Highly sensitive conductivity detection occurred with sharp and well-shaped peaks, leading to very efficient separations. The effects of sulfuric acid concentration added to the mobile phase, flow-rate, and column temperature on the retention volume of tested aromatic carboxylic acids was investigated. Retention times were found to be affected by the concentration of the analytes in the mobile phase and to some extent also by the addition of an organic modifier such as methanol to the injected water sample. Separation of sulfuric acid (SA), naphthalenetetracarboxylic acid (NTCA), phthalic acid (PA) and benzoic acid (BA) was satisfactory using this new approach. Detection limits were 0.66, 0.67, 0.42 and 0.86 microM and detector responses were linear in the range 1-100, 1-80, 2.5-100 and 10-40 microM, for SA, NTCA, PA and BA, respectively. Precision for retention times was 0.36% and for peak areas was 1.5%.     

Understanding ion deceleration lenses: What are the simplicity/performance trade-offs?

The traditional approach for obtaining highly collimated low energy (<200 eV) beams from high-energy (1–10 keV) sector mass spectrometers involves the use of a complex exponential deceleration lens assembly. Through ion optical modeling of the exponential lens and other less-complex lens designs, the fundamental features that contribute to deceleration lens performance are investigated. From this evaluation, a simple high-performance lens was designed, constructed, and characterized. The novel lens described here decelerates a 3-keV ion beam down to the 3-200-eV range while providing low angular divergence, excellent focusing, and good transmission.     

Quantitative validation of a flow-injection determination of penicillin in pharmaceutical formulations by means of a validation program based on an expert system

The quantitative validation of the results of a flow-injection determination of penicillin in pharmaceutical formulations is described. The validation procedure is done by using VALID, which is a generally applicable validation program based on an expert system program. The automated penicillin assay is based on the enzymatic hydrolysis of the penicillin to the corresponding penicilloic acid, which reacts with iodine generated on-line; the iodine consumption is detected amperometrically. The method is evaluated for applicability in pharmaceutical quality control. The complete validation procedure is described. During the program run, the system evaluates the calibration procedure, the drift of the analytical systemm and the effect of the sample matrix. The reliability of the flow-injection method is estimated by evaluating the maximum total error (MTE), which includes both random error and systematic error. The latter was assessed by comparing of the results of the flow-injection method with the results obtained by titration with mercury(II) as the reference method. The user requirement for the assay was an MTE of 10%. The validation procedure showed that the analytical method complied with the requirements for the major part of the concentration range (0.066–0.25 mM).     

Isolation and synthesis of vobparicine,a novel type dimeric indole alkaloid

From the rootbark of Tabernaemontana chippii a novel antimicrobially active dimeric indole alkaloid was isolated which was assigned structure $\text{1}$ on the basis of spectroscopic evidence and its synthesis.