Laundry Products Research
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pH
Salinity
Sodium
Phosphorus
Na & P
Sulphur

49 Laundry Detergents Powders
(updated 24th November 2007)

Lanfax Labs in association with Choice tested 49 powder detergents in early 2007, resulting in "Wash Only" data for 35 powders in front loaders and 35 powders in top loaders.  The report, published in "Choice" in the April edition (www.choice.com.au), includes results of performance testing (wash, rinse, gentleness, spin). The following pages relate only to the work completed by Lanfax Labs - the chemical analysis, and are presented independently of Choice.

WASH CYCLE ONLY

Introduction
Samples of these 49 laundry powder concentrates were provided to Lanfax Labs by Australian Consumers' Association (ACA) in January 2007.  The dose of detergent  (grams per litre - g/L) was calculated by ACA for the type of washing machine for which the product applied.  The amount of powder required was that used only in the "wash" of the complete washing cycle, therefore the water quality relates only to that wash load.  It is assumed that the remaining volume of water use will be for the deep rinse and spin rinse cycles and does not enter in the analysis.  The assumption is that all the chemicals are discharged with the "wash" water, which is not likely to be the case as chemicals will be retained in the clothes prior to the "rinse" cycle. The efficiency of the spin before rinse will determine how much chemical is carried over into the rinse.

Mixing
The calculated dose (g/L) was mixed with deionised water  (water from which most of the minerals have been removed) at 25oC to represent washing in cold rainwater. The sample was then shaken for 30 minutes to replicate the washing action.  A measurement was made of this sample to assess the undissolved product in the water.  This test is referred to as a "turbidity test".  Clean drinking water has a turbidity of less than 3 NTU (the units of measure) and the higher the number the more suspended material in the water, therefore the more incomplete the detergent had dissolved.

In many cases, some of the detergent had not dissolved in the water at 25oC, the samples were elevated to 38oC and re-agitated for a further 15 minutes and the turbidity again measured.  The results given show either as a pass or fail.  Pass means that all the product dissolved completely in the water, while fail means that there were still suspended particles in the water after the shaking.  The level of pass/fail was arbitrarily taken as 10 NTU. The use of hot water will enhance the dissolution of the powder in the water.

Analysis
The mixed detergent was analysed for pH, electrical conductivity (EC) and total alkalinity within one hour of  mixing.

A sample of the mixed detergent was acidified to pH <2 with nitric acid, filtered through a normal filter paper  (equivalent to Whatman No.21), and the filtered sample analysed using an Inductively Coupled Plasma (ICP) for boron, sodium, phosphorus, sulphur as well as calcium, magnesium and potassium.  The latter three elements are of only minor importance and are not reported here. Good Laboratory Practice (GLP) was used in the analysis of these samples.  Statistical variation is within +  5% for the sample analysed. Homogeneity of the detergents has not been assessed and it can only be assumed that the sample provided for analysis was representative of a larger (1 kg) packet.

Interpretation
The results are presented as a series of graphs.  For easy interpretation, the products have been ranked so that the lowest value start at the bottom of the graph and increase up the graph (the shorter the bar the lower the value).  In most cases the preferred choice is one of the shorter bars at the lower part of the chart.

Printing of graphs
 All the material on this website is unique to the research of Lanfax Labs and is offered to the general public for information purposes.  Any reprinting of the material must be referenced to the author  Dr Robert Patterson, Lanfax Labs, Armidale NSW.

From the side frame, choose the component in which you are interested - pH, Salinity, Sodium, Phosphorus, Na & P in combined graph, sulphur.

NOTE:  The products tested were purchased by Choice in early 2007.  Since that date, formulations may have changed without notification by the manufacturers. There is no way of knowing which products have been changed as the manufacturers do not indicate when formulations change.  A change of packet decoration may not mean a change in formulation.

None of this material is to be construed as either an endorsement for a product or a mark against a product. The information is made available simply to allow better choice through clearer understanding.  Under no circumstances will the author make a recommendation other than the comments made on this website.

© Dr Robert A. Patterson