N-(5-chloro-2-methoxyphenyl)-3-hydroxy-4-[[2-methoxy-5-[(phenylamino)carbonyl]phenyl]azo]naphthalene-2-carboxamide

Nanomaterial dustiness

Administrative data

Endpoint:

nanomaterial dustiness

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

EN 15051-2 (Workplace exposure. Measurement of the dustiness of bulk materials - Rotating drum method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: DIN 55992-1:2006

Version / remarks:

Determination of a parameter for the dust formation of pigments and extenders - Part 1: Rotation method

GLP compliance:

not specified

Type of method:

rotating cylinder

Test material

Test material information

Constituent 1

Reference substance name:

N-(5-chloro-2-methoxyphenyl)-3-hydroxy-4-[[2-methoxy-5-[(phenylamino)carbonyl]phenyl]azo]naphthalene-2-carboxamide

EC Number:

268-028-8

EC Name:

N-(5-chloro-2-methoxyphenyl)-3-hydroxy-4-[[2-methoxy-5-[(phenylamino)carbonyl]phenyl]azo]naphthalene-2-carboxamide

Cas Number:

67990-05-0

Molecular formula:

C32H25ClN4O5

IUPAC Name:

N-(5-chloro-2-methoxyphenyl)-3-hydroxy-4-[[2-methoxy-5-(phenylcarbamoyl)phenyl]diazenyl]-2-naphthamide

Test material form:

solid: nanoform

Data gathering

Instruments:

Heubach dust meter
The substance to be investigated is kept in motion in a dust generation device consisting of a rotating drum (volume: 2.2 L, 30 rpm) with integrated baffle plates. After a short period of upwards transportation the substance subsequently falls down within the drum. The airborne part of the dust is taken out of the drum by an axial air current of 20 L/min. In the process, both the airborne dust already contained in the substance and the airborne dust which has been newly generated through abrasion within the drum are collected.

Modified Heubach procedure
With the Heubach dust meter described above alone, it is not possible to separate inhalable, thoracic and alveolar dust fractions as defined in DIN EN 481. Therefore, the Heubach dust meter was modified by DMT in a way that a seven-stage cascade impactor was inserted instead of the filter. This interconnection of the rotating drum and the cascade impactor requires the following special approach: Whereas the rotating drum requires an air flow rate of approx. 20 L/min in accordance with the manufacturer’s specifications, the cascade impactor requires an air flow rate of 40 L/min in order to work properly. Therefore, 20 L/min of additional air is fed into the system via the coarse dust separator. By introducing a glass tubing, the dust generated in the rotating drum is now directly conveyed into the cascade impactor. The vessel used as the coarse dust separator in the original set-up now only serves as a tool to introduce additional air and for the purpose of visual inspection. The 20 L/min additional air required for the functioning of the cascade impactor are channelled off the exhaust air current of the cascade impactor via a three-way valve on the pressure side of the vacuum pump. Due to the present layout, the sampling tube of the cascade impactor is relatively long. However, due to the high air flow in the tube, which is approx. 10 m/s, any loss of sedimentation during the transportation of dust in the tube is excluded.

Determination of dust fractions with the cascade impactor
The cascade impactor is suitable for particle size determinations of airborne dust. Due to its small dimensions, it can be used e.g. for sampling in ducts or workplaces as well as in the laboratory for particle size determination of substance samples. The device works in accordance with the following principle: if a dust-containing air current encounters an obstacle and is thus redirected, the more inertial particles of the dust cannot follow this change in direction. The individual cascade stages of the impactor are designed in a way that the dust-containing air enters the first stage from above, is redirected and accelerated by a nozzle ring against the separator ring. While some of the dust particles deposit, the air current is redirected and reaches the second stage. From stage to stage the diameter of the nozzles is decreasing. Thus, the dust is progressively separated through redirections of the air current from the exterior to the interior and increasing air velocity and therefore, depositing particles on each stage according to the particle size. For a better adhesion of the deposited particles the rings are coated with a thin oil film. In the seven-stage cascade impactor used here the dust was separated into 7 fractions between approx. 0.3 μm and 30 μm. A scale with a resolution of 0.01 mg (Shimadzu AUW-220D, D-K-17702-01-00) was used to determine the mass of deposited quantities of dust on the individual impactor stages.

Results and discussion

Dustiness index

Dustiness index 1

Mean:

ca. 3.79 other: %

Remarks on result:

other: Relative amounts of used quantity

Remarks:

Dustiness, alveolar fraction

Dustiness index 2

Mean:

ca. 12.81 other: %

Remarks on result:

other: Relative amounts of used quantity

Remarks:

Dustiness, thoracic fraction

Dustiness index 3

Mean:

ca. 31.66 other: %

Remarks on result:

other: Relative amounts of used quantity

Remarks:

Dustiness, inhalable fraction

Any other information on results incl. tables

For PIGMENT RED-269, the respirable fraction represented 3.79 % of the quantity of the substance used under the modified Heubach procedure.

As the small rotation drum method according to EN 17199-4 might be more appropriate to assess the dustiness for this type of nanomaterial, a study based on this method is planned. However, due to the capacity of the laboratory it has been delayed and it will be conducted as soon as possible.