Kemisk analys

Ämnesområden: Djurfoder; Kemisk analys
Kommittébeteckning: SIS/TK 435 (Livsmedel och foder)
Källa: CEN
Svarsdatum: den 30 okt 2018
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This document specifies a method for the determination of organic acids in animal feeding stuffs by Ion

Chromatography with conductivity detection (IC-CD).

The method is intended to be used for the determination of formic acid, lactic acid, propionic acid, citric

acid, fumaric acid and malic acid as active substances in feed additives, premixtures, compound feed and

water and for screening of acetic acid in the same matrices. This method determines the total extractable

concentration of the above mentioned organic acids and their salts.

It is advisable that the user of this standar determine the working range of the method for each organic

acid. The lower limit of the working range depends on the matrix and the interferences encountered. A

working range between 10 [mg/l] and 100 [mg/l] should be achievable.

The method was successfully tested in an inter-laboratory study in concentrations between 0,02 % up to

27 % of the above mentioned organic acids.

NOTE Limitation occurs during simultaneous determination of high concentration of lactic acid and low

concentration of acetic acid. If the ratio of concentration of lactic acid to acetic acid exceeds factor 20, the

determination of acetic acid is not guaranteed.

On the basis of the referred working range, sample weight and extraction volume, limits of quantification

(LOQ), as calculated (Table 1) should be achievable.

Table 1 — Limits of quantification (LOQ)

Organic acid LOQ [mg/kg]

Formic acid 200

Lactic acid 200

Propionic acid 200

Citric acid 200

Fumaric acid 200

Acetic acid 200

Malic acid 200

 

Ämnesområden: Djurfoder; Kemisk analys
Kommittébeteckning: SIS/TK 435 (Livsmedel och foder)
Källa: CEN
Svarsdatum: den 30 okt 2018
Se merSe mindre
 

This document specifies a method for the determination of benzoic acid and sorbic acid in animal feeding stuffs by high-performance liquid chromatography method with ultraviolet detection (HPLC-UV).

The method is intended to be used for the determination of benzoic acid and sorbic acid as active substances in feed additives, premixtures and compound feed and for benzoic acid in water. This method determines the total extractable concentration of these organic acids and their salts.

It is advisable that the working range of the method is determined for each organic acid by the user of this standard. The lower limit of the working range depends on the matrix and the interferences encountered. It is advisable that a working range between 5 mg/l and 100 mg/l is accessible.

The method was successfully tested in an inter-laboratory study in concentrations between 0,02 % up to 9,0 %.

On the basis of the referred working range, sample weigh and extraction volume, limits of quantification (LOQ), as calculated (Table 1) on the basis of a wavelength of 230 nm, can be achievable.

Table 1 — Limits of quantification (LOQ) at 230 nm Organic acid

LOQ (mg/kg)

Benzoic acid

200

Sorbic acid

200

Kommittébeteckning: SIS/TK 435 (Livsmedel och foder)
Källa: CEN
Svarsdatum: den 30 okt 2018
Se merSe mindre
 

This document specifies a high performance liquid chromatographic – tandem mass spectrometry (LC-MS/MS) method for the simultaneous screening and/or determination of the eleven authorized coccidiostats (halofuginone, robenidine hydrochloride, nicarbazin, diclazuril, decoquinate, monensin sodium, salinomycin sodium, narasin, lasalocid sodium, semduramicin sodium and maduramicin ammonium alpha) contents in poultry, cattle and pig feed at additive and cross-contamination levels and of five non-registered coccidiostats (ethopabate, clopidol, ronidazole, dimetridazole and amprolium) at sub-additive levels and for the screening of the prohibited furazolidone antibiotic at sub-additive level, in the same matrices.

The range of application of the method is fit for the purpose of the screening and determination of all eleven coccidiostats at the values set by European legislation, of the non-registered coccidiostats and of the screening of the banned antibiotic.

Ämnesområden: Kemisk analys
Kommittébeteckning: SIS/TK 423 (Luftkvalitet)
Källa: ISO
Svarsdatum: den 21 nov 2018
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This part of ISO 6145 gives a brief overview of each of the dynamic techniques which are described in detail in the following parts of ISO 6145. This document provides basic information to support an informed choice for one or another method for the preparation of calibration gas mixtures. It also describes how these methods can be linked to national measurement standards to establish metrological traceability for the composition of the prepared gas mixtures.

Since all techniques are dynamic and rely on constant flow rates, this first part of ISO 6145 describes the calibration process by measurement of each individual flow rate generated by the device.

Methods are also provided for assessing the composition of the generated gas mixtures by comparison with an already validated calibration gas mixture.

This first part of ISO 6145 provides general requirements for the use and operation of dynamic methods for gas mixture preparation. It also includes the necessary expressions for calculating the calibration gas  composition and its associated uncertainty. 

Gas mixtures obtained by these dynamic methods can be used to calibrate or control gas analysers. 

The storage of dynamically prepared gas mixtures into bags or cylinders is beyond the scope of this part of ISO 6145.