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Laboratory tested quality: All information about our test methods

Glyphosate

Isotopically labeled standard is added to the sample material and the glyphosate is dissolved out of the sample with a mixture of methanol/hydrochloric acid by shaking. Interfering sample components are also extracted in this process. A portion of the sample extract is shaken with buffer solution and a derivatization reagent under heat, which significantly increases the sensitivity and selectivity of the subsequent measurement. The glyphosate contained in the solution is enriched via a special sorbent and interfering sample components are removed with water and dichloromethane. The purified sample extract is gently concentrated and measured and evaluated by HPLC and mass selective detection (HPLC-MSMS) against a reference solution with known glyphosate content. The results are corrected against the recovery of the isotopically labeled standard. The method described also detects AMPA and glufosinate.

Microbiology

Microbiology testing is performed according to the specifications of the German Society for Hygiene and Microbiology for food supplements. A representative sample size is used for microbiological testing and specific and selective methods are performed per target organism. The number of microorganisms is determined by growth and subsequent counting of colonies. Finally, the result is calculated depending on the evaluation method, e.g. per Petri dish and related to the sample quantity used.

Nicotine

The dry samples are moistened with water and adjusted to a pH value >10 using sodium hydroxide solution. Nicotine is dissolved from the sample using acetonitrile (solid/liquid extraction) and purified by addition of various salts and centrifugation. The sample extract is further concentrated to reduce the limit of quantification and measured by LC-MS/MS. Quantification is carried out taking into account an internal standard to compensate for losses in reprocessing and effects due to the matrix.

Pesticides QuEChERS

The pesticide residues are extracted from the respective sample matrix with acetonitrile and the pH is buffered by adding various salts. After phase separation, the organic phase is further purified, centrifuged and concentrated depending on the matrix. The extracts obtained are each analyzed by GC-MS/MS and LC-MS/MS, allowing the detection of more than 600 different pesticides. The spectrum is continuously adapted and expanded to the legal requirement and developments in food production. Detection and quantification is performed taking into account various internal standards and all required quality assurance measures.

Phenoxyalkanecarboxylic acids

The phenoxyalkanecarboxylic acids contained in the sample material are extracted with a water/acetonitrile mixture, with simultaneous hydrolysis of possible esters by addition of sodium hydroxide solution. After cooling and subsequent neutralization, phase separation between water and acetonitrile is obtained by adding magnesium sulfate and sodium chloride. The analytes contained in the solution are enriched via a special sorbent and interfering sample components are removed with alkali and methanol. The purified sample extract is gently concentrated and measured and evaluated by HPLC and mass selective detection (HPLC-MS/MS) against a reference solution with known contents. Results are corrected against recoveries of isotopically labeled standards.

Polar pesticides - multi-method

Very polar analytes cannot be detected by the pesticide multimethod (QuEChERS), so a separate multimethod was developed for the following active ingredients in diverse matrices:

  • Bromide and chloride (for bromide/chloride ratio)
  • Chlorate and perchlorate
  • Chlormequat and mepiquat (fruits and vegetables only)
  • Ethephon
  • Fosetyl and phosphonic acid

The residues are extracted from the sample matrix with water and acidified methanol. The mixture is purified in a matrix-dependent manner, then centrifuged, filtered and analyzed directly by LC-MS/MS. Two different LC-MS/MS methods are used, allowing the simultaneous analysis of different combinations of active ingredients. For quantification, isotopically labeled analogs of the analytes are used as internal standards. These internal standards are added at the beginning of the extraction, so that all factors that have an influence on the result, such as volume fluctuations, matrix effects in preparation and measurement are compensated.

Polycyclic aromatic hydrocarbons (PAH) 4s

The PAHs are extracted from the food using a mixture of 2-propanol/n-hexane by shaking and ultrasonication. The obtained extract is then further purified via two sequential solid phase extraction steps. The purified sample extract is gently concentrated to obtain lower limits of quantitation. The measurement is performed by HPLC and fluorescence detection against a reference solution with known PAH content.

Pyrrolizidine alkaloids

The contained pyrrolizidine alkaloids (including N-oxides) are extracted using sulfuric acid solution in an ultrasonic bath and the obtained extract is neutralized, centrifuged and filtered. The separation and detection is performed by LC-MS/MS, the chromatographic method is optimized for highest separation performance of different alkaloids and successfully validated for various food groups.

Heavy metals

Heavy metals must first be released from the food before the actual analysis by ICP-MS. For this purpose, the well homogenized sample is weighed into a pressure vessel and digested with nitric acid at high temperature and pressure in a special microwave oven. The test solution obtained by pressure digestion is atomized and the aerosol is transferred to an inductively coupled high-frequency argon plasma (ICP). The high temperature of the plasma serves to dry the aerosol and atomize and ionize the elements. After extraction from the plasma via a system of cone-shaped pinholes (sampler and skimmer), the ions are transferred to a mass spectrometer where they are separated according to their mass-to-charge ratio and determined with high sensitivity using a pulse (number) and/or analog detector.

Tropane alkaloids

The tropane alkaloids contained (atropine and scopolalim) are extracted by means of sulfuric acid solution in an ultrasonic bath and the obtained extract is neutralized, centrifuged and filtered. Separation and detection is performed by LC-MS/MS. For quantification, internal standards are used to compensate for losses during reprocessing and effects due to the matrix.

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