Pavla Foltynová

Explosive Backpacks in Old Termite Workers

As Neocapritermes taracua termites age, they develop a suicidal toxic apparatus that bursts during aggressive encounters. By nature, defensive behavior is risky. In social insects, such behavior is more likely to occur in individuals whose potential for other tasks is diminished. We show that workers of the termite Neocapritermes taracua develop an exceptional two-component suicidal apparatus consisting of copper-containing protein crystals, stored in external pouches, and internal salivary glands. During aggressive encounters, their bodies rupture, and the crystals react with the salivary gland secretion to produce a toxic droplet. Both the amount of defensive substances and the readiness to explode increase with workers’ age, as their food-collecting ability declines.

MALDI MS and ICP MS Detection of a Single CE Separation Record: A Tool for Metalloproteomics

In this work, a novel approach based on off-line coupling of a single run of capillary electrophoresis (CE) separation to both matrix-assisted laser desorption/ionization (MALDI) and substrate-assisted laser desorption inductively coupled plasma (SALD ICP) mass spectrometry (MS) is presented. Using a liquid junction and subatmospheric deposition chamber, CE fractions were extracted from a separation capillary and collected as 20-nL droplets on a custom-built polyethylene terephthalate glycol (PETG) target plate coated with a 10-nm gold layer which guaranteed compatibility with both MALDI and SALD ICP techniques. The MALDI matrix solution was then added to the produced spots. After it was dried, the separation record was consecutively analyzed in MALDI MS and ICP MS instruments. Thus, both proteomic and metallomic information was obtained off-line from a single CE run. The concept was demonstrated by the analysis of a mixture of rabbit liver metallothionein isoforms. In an additional study, the droplets representing the archived separation record were alternately mixed with two different MALDI matrices to obtain complementary information on both the apoproteins and their complexes with metals from a single separation run. The presented technique is a viable alternative to online coupling of column separation to electrospray MS and nebulizer ICP MS.

Diode Laser Thermal Vaporization Inductively Coupled Plasma Mass Spectrometry

An approach of sample introduction for inductively coupled mass spectrometry (ICPMS), diode laser thermal vaporization (DLTV) is described. The method allows quantitative determination of metals in submicroliter volumes of liquid samples. Laser power is sufficient to induce pyrolysis of a suitable substrate with the deposited sample leading to aerosol generation. Unlike existing sample introduction systems based on laser ablation, it uses a NIR diode laser rather than an expensive high-energy pulsed laser. For certain elements, this sample introduction technique may serve as an alternative to solution analysis with conventional nebulizers. Using a prearranged calibration set, DLTV ICPMS provides rapid and reproducible sample analysis (RSD ~ 10%). Sample preparation is fast and simple, and the prepared samples can easily be archived and transported. The limits of detection for Co, Ni, Zn, Mo, Cd, Sn, and Pb deposited on the preprinted paper were found to be in the range of 0.4-30 pg. The method was characterized, optimized, and applied to the determination of Co in a drug preparation, Pb in whole blood, and Sn in food samples without any sample pretreatment.

Diode laser thermal vaporization ICP MS with a simple tubular cell for determination of lead and cadmium in whole blood

A new low-cost device suitable for the recently presented sample introduction technique to inductively coupled plasma mass spectrometry (ICP MS), diode laser thermal vaporization (DLTV), is described. DLTV ICP MS is suitable for quantitative elemental analysis of low volume liquid samples and offers an alternative to commonly used liquid sample introduction into inductively coupled plasma. In contrast to the existing sample introduction systems based on laser ablation, the technique relies on low-cost components: a diode laser, a simple laboratory-built cell and a strip of filter paper. The aerosol generation by DLTV is carried out in a simple cell made up of a glass tube, a near infrared continuous-wave diode laser and a common syringe pump. The cell is characterized by minimal dead volume, which reduces turbulent flow and provides very fast wash-out. The paper substrate can hold up to 24 samples; an analysis time per sample of ∼4.7 s has been achieved. The device performance was optimized, compared to a commercial ablation system and applied to the determination of lead and cadmium in whole human blood without any sample treatment. A prearranged calibration set was printed on the paper strip using a piezoelectric dispenser.