Kimmo Himberg

The effect of water treatment processes on the removal of hepatotoxins fromMicrocystis andOscillatoria cyanobacteria: A laboratory study

The behaviour of hepatotoxins fromMicrocystis andOscillatoria cyanobacteria in some common water treatment processes was investigated on the laboratory scale in order to obtain data on their potential transfer to drinking water. Two toxins were separated from both of the freeze-dried cyanobacterial materials used in the experiments, a natural bloom consisting ofM. wesenbergii andM. viridis and a laboratory-grown culture ofO. agardhii. The concentrations of all four toxins before the treatments were between 30 and 60 μg/1. The investigated water treatment processes, selected from among methods applied in Finland, were: (1) Al2(SO4)3 flocculation with sand filtration and chlorination; (2) FeCl3 flocculation with sand filtration and chlorination; (3) addition of activated carbon powder with Al2(SO4)3 flocculation, sand filtration and chlorination; (4) Al2(SO4) flocculation with sand filtration, activated carbon filtration and chlorination; and (5) ozonation with Al2(SO4)3 flocculation, sand filtration and chlorination. The conventional flocculation-filtration-chlorination procedures resulted in a relatively small decrease in the toxin concentrations. Activated carbon powder in low doses did not improve the results, but activated carbon filtration as well as ozonation completely removed the toxins. The toxin concentrations were determined by HPLC. The proper functioning of the treatment processes was monitored by measurement of the KMnO4 value, turbidity and flocculation chemical residues.

The Identification of Gunshot Residue Particles from Lead-Free Sintox Ammunition

Scanning electron microscopy combined with energy dispersive X-ray analysis (SEM/EDX) was used to identify the gunshot residue (GSR) particles discharged by lead-free Sintox ammunition. Sintox GSR particles are characterized by spheroidal particles mainly consisting of titanium (Ti) and zinc (Zn). The results obtained in this study are in agreement with the hypothesis that GSR particles are formed by rapid condensation and solidification of vaporized and molten primer and bullet materials as a result of sudden temperature quench. The surface morphology of Ti-Zn particles is an essential criterion for their identification as gunshot residue particles and for discrimination against Ti-Zn environmental particles.

Screening for cyanobacterial toxins in bloom and strain samples by thin layer chromatography

Two thin layer chromatographic (TLC) procedures were evaluated for the capacity screening of cyanobacterial peptide hepatotoxins and anatoxin-a in laboratory-cultured strain samples and in natural bloom samples. Seventy-five samples previously investigated with the reference methods, the chief of which was mouse bioassay, were analyzed blindly by TLC. Forty-three of the samples were hepatotoxic according to the reference methods, and 39 of them were found to contain peptide hepatotoxins by TLC coupled to u.v.-densitometry. Seven samples contained anatoxin-a according to the reference methods, and five of these were found to contain anatoxin-a by TLC, using derivatization with Fast Black K salt. Four of the samples which were neurotoxic by mouse bioassay also contained hepatotoxins by TLC. Twenty-four samples were nontoxic according to the reference methods, and in 23 of these no toxins were found by TLC either.

Facile detection of anatoxin-a in algal material by thin-layer chromatography with Fast Black K salt

A method for facile high-capacity screening of algal samples for anatoxin-a (ANTX-a), a potent neurotoxin of Anabaena flos-aquae, is presented. The method is based on in situ colour reaction of algal extracts containing ANTX-a on a thin-layer chromatographic plate with the diazonium reagent Fast Black K salt, and subsequent separation of the orange-red product. The product, shown to be a stable 3,3-dialkyltriazene, is derived from a reaction involving the aliphatic secondary amino group of ANTX-a. The detection limit for ANTX-a is 10 micrograms g-1 of lyophilized algal material, which is comparable to earlier methods using more complex instrumentation.

Removal of nodularin from brackish water with reverse osmosis or vacuum distillation

Abstract Reverse osmosis and vacuum distillation are commonly used for desalination when purifying drinking water from sea or brackish water. The ability of these methods to remove nodularin, a hepatotoxin produced by the cyanobacteria Nodularia spumigena , was investigated. For this purpose, natural brackish water was contaminated with toxic algal material. Nodularin concentrations of raw and purified water were determined after a solid-phase extraction procedure employing high-performance liquid chromatography. In the case of reverse osmosis (Freshwater R MT 5000B) the initial nodularin concentration was 10.0 μg/litre, but, after a concentration programme which included recycling the wastewater and discharging the purified water, the final nodularin concentration after 19.5 h was 32.3 μg/litre. The nodularin concentration of the purified water always remained below the limit of quantitation, which was 0.5 μg/litre, but, by the end of the experiment, when both the nodularin and salt concentrations had increased threefold, traces of nodularin were detected. The specific conductivity of the purified water increased simultaneously. In the case of vacuum distillation, the nodularin concentration of brackish raw water was 70 μg/litre and the test was performed using a Rotavapor R-114 instrument at 60°C to simulate an existing purification method. No nodularin was detected in the distillate. Both reverse osmosis and vacuum distillation removed nodularin effectively. When brackish water is to be purified by reverse osmosis, conductivity measurement can be used to monitor the effectiveness of the purification result.

Determination of toxic PCB congeners in biological samples by multidimensional gas chromatography-mass spectrometry (GC/GC/MS)

SummaryMultidimensional gas chromatography-mass spectrometry (GC/GC/MS) was used for the determination of coplanar PCB congeners in biological samples. A quadrupole low resolution mass spectrometer was used as the main detector in order to increase the reliability of identification and enable the use of 13C-labelled internal standards. The technique was capable to separate these toxic congeners from the complex matrix and decreased the need of sample purification.

Automated gas chromatographic amphetamine profiling

A computerized procedure is presented for profiling and comparison of illicit amphetamine seizures. The system involves an optimized capillary gas chromatographic separation step followed by peak identification by linear retention indices. An individual amphetamine street sample can be recognized after up to 14 identified characteristic peaks are mathematically compared with the data in an intralaboratory database via an exponential comparison algorithm. The procedure enables rapid screening: the GC analysis of an unknown sample and computer comparison against several hundred samples is performed in just over an hour.

Detection of Trace Levels of Gasoline in Arson Cases by Gas Chromatography-Mass Spectrometry with an Automatic On-Line Thermal Desorber

A method for the analysis of trace levels of gasoline in arson debris using an automatic thermal desorber (TD) and commercial Tenax adsorbent tubes is described. First, a static headspace screening test is performed by gas chromatography using a flame ionization detector (GC-FID). Suspected gasoline is reanalyzed by gas chromatography-mass spectrometry (GC-MS). Gasoline traces smaller than 10 μL in a 1 liter volume are analyzed by a dynamic heated headspace procedure with thermal desorption and GC-MS after adsorption on 45 mg Tenax tubes. The desorption of adsorbed vapors is carried out by heating the tubes; the analytes are focused in cryogenic units cooled with liquid nitrogen. The cryofocused vapor sample is flash-heated for injection into the capillary column of the GC. The dynamic heated headspace technique (TD-GC-MS) is suitable for analyses of trace amounts of gasoline (0.1–10 µL in 1 liter volume).

Real-time controlled multidimensional gas chromatography with electronic pressure control: application to chlorobiphenyl analysis

Multidimensional gas chromatography was applied to the quantitative determination of planar chlorobiphenyls (PCBs) in commercial PCB mixtures. The instrumental setup is based on real-time controlled column switching in which the heartcuts are elucidated through retention indices calculated by linear extrapolation from the retention times of n-alkanes as reference compounds. Electronic pressure control providing pressure programming was used to adjust the pressure at the injector and at the mid-point of the column tandem.

Fingerprint Detection on Counterfeit US

Two seizures of counterfeit 100 US