Santicizer 2148

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-05-03 to 1999-06-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))

Version / remarks:

DRAFT document, July 1997

Deviations:

not applicable

GLP compliance:

not specified

Type of method:

HPLC estimation method

Media:

sewage sludge

Radiolabelling:

not specified

Test temperature:

35°C

Details on study design: HPLC method:

A HPLC with a spectrophotometric detector set to read the absorbances at 210 nm. The stationary phase was a cyanopropyl chemically bound resin on silica basis (Hypersil BDS-CN). The mobile phase was 55/45 (v/v) methanol/Milli-Q water. A temperature-controlled column compartment at 35°C was used.

Stock solutions of the reference substances (see Table) in methanol at concentrations between 1.1 g/L and 1.8 g/L were used. For calibration, each stock solution was diluted by a factor 100 with methanol.

A 2.3 g/L solution of formamide in methanol was diluted by a factor 10 with methanol. This solution was used for the determination of t0 (retention time of the unretarded component).

A 1.3 g/L test solution of Santicizer 2148 plasticizer was prepared in methanol.

The solutions were injected in the following sequence: nine reference substance solutions; methanol, formamide solution; test solution (in duplicate), methanol, nine reference substance solutions, and the formamide solution. The chromatograms of the test solution and formamide were recorded for 5 to 10 minutes. The chromatograms of the test solution were recorded for 25 or 35 minutes. The chromoatograms of methanol were recorded for 10 to 35 minutes.

Key result

Type:

log Koc

Value:

>= 6.1 - <= 7.3 dimensionless

Temp.:

35 °C

Remarks on result:

not measured/tested

Details on results (HPLC method):

In the HPLC chromatograms of SANTICIZER 2148 PLASTICIZER, using detection at 210 nm and 55/45 (v/v) methanol/Milli-Q water as mobile phase, one large broad band and two small test substances peaks were observed. It was assumed that the small peaks derive from impurities in the test substance and that the broad derives from the five phosphoric acid esters,
The t0 was determined to be 2.05 minutes as a mean value of both measurements (i.e. 2.10 and 2.00 minutes)

Table 1 shows the determination of log K_OCand K_OCof SANTICIZER 2148 PLASTICIZER using 55/45 (v/v) methanol/Milli-Q waters as the mobile phase

Substance	tr­^1	k^’	log k’	log KOC	KOC
Reference substance
Phenol	2.233	0.09	-1.051	1.32
N,N-dimethylbenzamide	2.226	0.09	-1.069	1.52
Methylbenzoate	2.421	0.18	-0.744	1.80
3,5-Dinitrobenzamide	2.402	0.17	-0.767	2.31
Naphtalene	2.944	0.44	-0.361	2.75
Mercaptodimethur	2.692	0.31	-0.505	3.10
Fenthion	3.729	0.82	-0.087	3.31
Phenantrene	3.630	0.77	-0.113	4.09
2,4-DDT	5.581	1.72	0.236	5.63
Test substance
Peak 1 (impurity)	2.251	0.10	-1.011	1.2^2	16
Peak 2 (impurity)	3.281	0.60	-0.222	3.8^3	6.3*10^3
Start band (major components)	8.52	3.20	0.505	6.1^2	1.3*10^6
End band (major components)	17.65	7.61	0.881	7.3^2	2.0*10^7

¹ mean value of the retention times of two chromatograms

² extrapolated from the regression line: log K^’= 0.3122 log K^‘_OC-1.3915 (r=0.946, n=9)

³ interpolated from the regression line: log K^’= 0.3122 log K^’_OC-1.3915 (r=0.946, n=9)

Validity criteria fulfilled:

not specified

Conclusions:

For the five phosphoric acid esters, the log KOC and KOC were given as a range of 6.1 - 7.3 and (0.13 - 2.0)*10^7, respectively.

Executive summary:

The adsorption coefficient (K_OC) in soil and on sewage sludge was estimated using HPLC. According to the information supplied by the sponsor, SANTICIZER 2148 PLASTICIZER is a mixture of five organic esters prepared from phosphoric acid. For the five phosphoric acid esters, the log K_OC and K_OC were given as a range of 6.1 - 7.3 and (0.13-2.0)*10⁷, respectively.

Description of key information

For the five phosphoric acid ester components of Santicizer 2148, the log K_OC and K_OC were determined to be in the range of 6.1 - 7.3 and (0.13 - 2.0)*10⁷, respectively.

Additional information

The adsorption coefficient (K_OC) in soil and on sewage sludge was estimated using HPLC (NOTOX B.V., 1999i). According to the information supplied by the sponsor, SANTICIZER 2148 PLASTICIZER is a mixture of five organic esters prepared from phosphoric acid. For the five phosphoric acid esters, the log K_OC and K_OC were given as a range of 6.1 - 7.3 and (0.13 - 2.0)*10⁷, respectively.