Analytical method for nonionic surfactants in laboratory biodegradation and environmental studies

The Environmental Chemistry, Fate and Effects of Nonionic Surfactants

“…The nonionic is reacted with ammonium cobaltothiocyanate in aqueous solution to form a coloured ion association complex which is readily extractable into dichloromethane. The intensity of the DCM extract is measured at 620 nm (Boyer et al [36]). The CTAS procedure has been critically reviewed by Nozawa et al [37].…”

Distribution and survival of nonionic surfactants in the surface, sea and groundwater of Israel

“…Water samples from selected sites, including polluted rivers, urban and industrial sewage, near shore water, seawater, and water wells mainly in the northern part of Israel (see Figure 1), were collected periodically, using The nonionic detergent contents were determined colorimetrically by using preprepared calibration curves (absorbance, at 620 nm, of the thiocyanatenonionic surfactant complex vs. the concentration of the nonionic ethoxylate surfactant) in accordance with the modified Soap and Detergent Associationcobaltothiocyanate active substance method (SDA-CTAS) method [5,24,25]. Later, the high performance liquid Chromatograph (HPLC) method was used to determine the nonionic detergent concentrations in environmental samples [26].…”

A slow-release system of bacterial cellulose gel and nanoparticles for hydrophobic active ingredients

“…PEO-b-PCL nanoparticle release from BC gels BC gels containing PEO-b-PCL nanoparticles were placed into acetic acid-sodium acetate buffer (pH 5.2) (2 mL) at 37 C. The amount of released PEO-b-PCL was measured using an analytical method for nonionic surfactants (Boyer et al, 1977), which has been used to measure cobalt thiocyanate active substance (CTAS) in biodegradation and environmental studies. Cobalt thiocyanate solution was prepared by dissolving Co(NO 3 )Á6H 2 O (30 g) and NH 4 SCN (200 g) in 1 L of distilled water.…”

“…To determine the amount of nanoparticles incorporated into the BC gel, PEO(5000)-b-PCL(5000) and PEO(5000)-b-PCL(10,000) nanoparticle residue suspensions were subjected to measurement using the CTAS method after the BC gel was removed (Boyer et al, 1977). The incorporation ratios for PEO(5000)-b-PCL(5000) and PEO(5000)-b-PCL(10,000) nanoparticles were 99.7% and 93.6%, respectively.…”

“…In vitro release studies 3.5.1. Copolymer release from BC gel The amount of copolymer (formed and unformed nanoparticle ratio) released from the BC gel in acetic acid-sodium acetate buffer (pH 5.2) at 37 C was determined at defined time intervals using the CTAS method (Boyer et al, 1977). The results show that the combination of BC gel and nanoparticles can be used as a slowrelease system (Fig.…”