Multiresidue screening of pesticides in foods using retention time locking, GC-AED, database search, and GC/MS identification

Fruit and vegetable extracts were screened for over 400 pesticides by gas chromatography with atomic emission detection (GC-AED) and an experimental database. A technique called retention time locking was used to match GC-AED and GC with mass spectrometry (MS) retention times to those of the database. Samples were analyzed for sulfur, nitrogen, phosphorus, and chlorine by GC-AED. Possible pesticides were suggested by database search and identified by GC/MS. Forty-four pesticide standards were analyzed to determine the precision of retention time matching and the accuracy of the database search. Analytical retention times matched database retention times within 0.32 min. Using elemental criteria, the database search identified the correct compound for 41 of 44 pesticide standards. For blind spikes of fruit and vegetable extracts, the database suggested 22 of 26 spiked pesticides as matches. Nineteen were identified by GC/MS. The combination of retention time locking, GC-AED, database search, and GC/MS can be a powerful tool for identifying pesticides in a complex matrix.     

Joint production of ϕ mesons andπ ±,π 0,p,\bar p,K s 0 andK ± in hadronic interactions

The joint production of ? mesons andπ ^±,π ⁰,p, \(\bar p\) ,K _s ⁰ andK ^± is investigated using a sample of 600,000 inclusive ? meson events obtained in hadron Be interactions with incidentπ ^±,p, \(\bar p\) andK ^± beams. Evidence is presented for the joint production of ? mesons and strange particles produced with non-strange incident beams. With incidentK ^± beam the number of additional strange particles is suppressed. The results are found to be in agreement with the qualitative predictions of a parton fusion model. The comparison with the Lund model for lowp _T processes is fair.     

InclusiveK *0(890) and\bar K*^0 (890) production on beryllium byK − and π− at 175 GeV

The reactions \(K^ - Be \to {}^(\bar K^) *^0 (890)X,\pi ^ - Be \to {}^(\bar K^) *^0 (890)X\) , have been studied in a 175 GeV unseparated hadron beam in the kinematic range 0<x _F <1.0 andp _T ² <5 GeV². Integrated cross-sections and the dependence of the cross-sections on the longitudinal and transverse momentum are presented, together with quark counting rules predictions. The nuclear dependence ofK ^? fragmentation intoK ^*0(890) with respect to Feynmanx is investigated from hydrogen to beryllium.     

Lifetimes of charged and neutralD mesons

We have measured the lifetimes of hadronically produced charged and neutralD mesons using silicon microstrip detectors and an active silicon target in the NA32 spectrometer at the CERN SPS. We obtainτ _D± = (10.9± _1.5 ^1.9 )·10^?13s andτ _D ^(?)10 = (4.2±0.5)·10^?13s based on 59 and 90 fully reconstructed decays respectively, giving a ratioτ _D±/τ _D ^(?)10 of 2.6 ±0.5.     

The impact of the natural sciences on archaeology

This article reviews some of the applications of physics to the solution of archaeological problems. The use of magnetic, resistivity and electromagnetic surveying techniques for the location of buried features is described. Various methods of age determination are outlined while the problems associated with radiocarbon dating of organic material and thermoluminescent dating of pottery are discussed in detail. The techniques, including petrological examination, chemical analysis and isotopic analysis, employed in the physical examination of archaeological artefacts are described. Examples of the application of these techniques in establishing the source of the raw materials used in pottery, metal and stone implements and in elucidating the techniques of manufacture of pottery and metal objects are also given.     

μSR studies of the vortex lattice in high‐Tc and other superconductors

We review some of the assumptions made in the use of muon spin rotation in superconductors: i.e. that the muons are implanted at random positions in the flux lattice, remain static after implantation and do not appreciably affect the properties of the surrounding superconductor; also that the flux lines are straight and static, and that the observed muon rotation frequency spectrum reflects the microscopic distribution of field values. We shall show how evidence for and against the truth of these assumptions in particular cases may be obtained from the μSR results themselves or by comparison with other measurements, and how this in turn may lead to deeper understanding of flux line structure and motion in superconductors. This revised version was published online in August 2006 with corrections to the Cover Date.     

Ultrasonically induced phthalocyanine degradation: decolouration vs. metal release

The ultrasonically induced degradations of nickel(II) 2,9,16,23-tetraphenoxy-29H, 31H-phthalocyanine and vanadyl 2,9,16,23-tetraphenoxy-29H, 31H-phthalocyanine in a biphasic system consisting of chloroform and water are investigated. Decolourisation of the organic phase containing the metallo-phthalocyanines is found to occur rapidly (approximately minutes for 8 ml of ca. 5 microM solution). Analysis of the aqueous solute via ICP-OES, reveals significant amounts of the released nickel ultimately transfers into the aqueous phase but at a rate much slower than that of decolourisation, whereas the vanadium remains within the organic phase suggesting only partial degradation despite efficient decolourisation.     

Inclusive\bar K^{0*} (892) andK 0*(892) production on silicon by 200 GeVK − andπ −

The production of the neutralK ^? (892) resonances by 200 GeVK ^? andπ ^? has been studied over the kinematic range 0.0<x _f<1.0 andp _t ² <5.0 GeV². Longitudinal and transverse momentum distributions are presented. In addition the decay angular distributions inK ^? fragmentation to \(\bar K^{0*} \) have been investigated.