Abstract: The MALDI mass spectrometry method comprises the provision of a test composition comprising an analyte, a matrix material, a solvent for the matrix material and an antisolvent, which facilitates crystallization of the matrix material on the analyte subsequent to droplet generation. Due to the crystallization, a non-spherical particle morphology of the test sample is obtained. The test sample with a non-spherical particle morphology can be distinguished from test samples with an at least substantially spherical particle morphology by sensing a morphology parameter. Based on the sensing result, test samples with a non-spherical particle morphology are selected for ionization and mass spectrometry. The antisolvent is for instance water, and the solvent is an organic solvent. The formed crystals are in one embodiment crystallized in a hydrate form. As a result, a signature-rich spectrum is obtained.

Abstract: The method for the diagnosis of a microbial infection in an organism makes use thereof that said microbial infection is at least partially present as elementary bodies in cellular material of the organism. The method comprises the steps of (1) providing a sample of cellular material from the organism; (2) processing the sample to obtain a test composition, that is enriched in elementary bodies, in so far as the sample contains any elementary bodies; and (3) Subjecting a volume of the test composition comprising at most a predetermined maximum of elementary bodies to a MALDI mass spectrometry method to identify presence of the microbial infection. The sample processing more particularly involves cell lysis and separation of elementary bodies from the lysed cell material. Subsequently, the elementary bodies (and any further material attached thereto) are contacted with a matrix material, that facilitates the MALDI mass spectrometry.

Abstract: The MALDI mass spectrometry method comprises the provision of a test composition comprising an analyte, a matrix material, a solvent for the matrix material and an antisolvent, which facilitates crystallization of the matrix material on the analyte subsequent to droplet generation. Due to the crystallization, a non-spherical particle morphology of the test sample is obtained. The test sample with a non-spherical particle morphology can be distinguished from test samples with an at least substantially spherical particle morphology by sensing a morphology parameter. Based on the sensing result, test samples with a non-spherical particle morphology are selected for ionization and mass spectrometry. The antisolvent is for instance water, and the solvent is an organic solvent. The formed crystals are in one embodiment crystallized in a hydrate form.

Abstract: The invention relates to a method for classification of a sample on the basis of spectral data, a method for creating a database and a method for using this database, and corresponding computer program, data storage medium and system. The method comprises: a) obtaining at least two sets of first spectra for use as reference spectra, each set comprising spectra of reference samples belonging to the same class; b) determining for each of the reference spectra the value of the same at least one quantity related to a spectral feature; c) associating a probability to different values of the quantity on the basis of the determined values; d) obtaining a spectrum from the sample and determining the value of the same at least one quantity of this spectrum; and e) calculating on the basis of the probabilities and the value of the quantity for the obtained spectrum for each of said at least two classes a probability that the sample belongs to that class.