Standard curve 20 Triton

The initial mixture and each time point are then assayed for doxorubicin and lipid. Lipid concentrations can be quantified by the phosphate assay (see above) or by liquid scintillation counting of an appropriate radiolabel. Doxorubicin is quantified by an absorbance assay (see below). The percent uptake at any time point (e.g., t = 30 minutes) is determined by %-uptake = [(D/L), =30minutes] x 100/[(D/L) inuiai]. Doxorubicin can be assayed by both a fluorescence assay and an absorbance assay, but we find the latter to be more accurate. The standard curve consists of four to five cuvettes containing 0 to 150 nmol doxorubicin in a volume of 0.1 mL samples to be assayed are of the same volume. To each tube is added 0.9 mL of 1% (v/v) Triton X-100 (in water) solution. For saturated lipid systems such as DSPC/Chol, the tubes should be heated in a boiling water bath for 10 to 15 seconds, until the detergent turns cloudy. Samples are allowed to cool, and absorbance is read at 480 nm on a UV/Visible spectrophotometer. 

Precautions should also be taken with the aqueous solvents used to prepare standard working solutions in order to avoid adsorption problems, especially at low concentrations. To minimize adsorption during standard curve and validation sample (VS)/QC preparations, aliquots of the high-concentration stock solutions should be spiked promptly into the control blank plasma to prepare the standards and VS/QC. Once the compounds are in an environment of protein solutions, the adsorption problem is negligible. If there is a problem, however, adding or pre-rinsing with a solution of protein or a chaotropic agent (e. g., Tween, Triton X-100 or CHAPS) may help to alleviate the problem. 

The mannose residues coupled to the liposomes were quantified by the resorcinol-sulfuric acid method (27). The standard curve was established as follows to a 12.2x100 mm glass tube containing 2-12 pg of D-mannose in 200 pL water were added successively 20 pL of 0.1% (w/v) Triton X-100,200 pL of a 6 mg/mL aqueous solution of resorcinol and 1 mL of 75% (v/v) H SO,. 

Figure 7.10. Standard curves for 2,4-dichlorophenoxyacetic acid (2,4-D).Displacement of CMMC from the 2,4-D-imprinted MIP by 2,4-D (I), CPOAc ( ) and POAc (A) in a) 20 mM phosphate buffer, pFf 7, 0.1% Triton X-100 b) acetonitrile. Reprinted with permission from Haupt K, Mayes AG, Mosbach K. Herbicide assay using an imprinted polymer-based system analogous to competitive fluoroimmunoassays. Anal Chem 1998 70 3936-3939. 1998 American Chemical Society...

The only compounds found to give excess interfering colour in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100 and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls. The assay is non-linear and requires a standard curve. 

Fig. 3.15 ASSWV of Cd +. Dependence of inverse values of aceumulation times which correspond to the minima of (7p vs. 4oo) curves (shown in Fig. 3.14) on the standard additions of Triton X-100. Experimental eonditions as in Fig. 3.14 (reprinted from [247] with permission)...

Fig. 90. Calibration curve of an enzyme electrode for the determination of total cholesterol. cholesterol standard solution containing 10% Triton X-100, X control serum containing free and esterified cholesterol. (Redrawn from Wollenberger et al., 1983).

Prepare standards of 0, 2, 5 and 10//g/L manganese in 0.1% v/v Triton X-100 solution. Dilute a blood sample low in manganese 1 -t- 3 with the standards to prepare calibration solutions equivalent to 0, 6, 15 and 30 //g/L manganese in the blood samples. Samples are diluted 1 -l- 3 with the zero standard. A blank of distilled water diluted similarly is also prepared. 10 //L aliquots of prepared standards, blank and samples are analysed in duplicate in the furnace using the programme for serum shown in Table 2. Subtract the peak absorbance of the standards from the value for the zero standard and plot a calibration curve. From the peak absorbances of the samples, subtract the value for the reagent blank and read the concentration from the calibration cun/e. 

The peroXide/cata1ase system was selected for study because of the difficulties found with the fiber optic sensor described above. The FIA carrier contained Triton-X as a surface active agent to reduce bubble formation. Typical FIA flow characteristics were ml/min, and a sample loop of 80 uL. Typical sensor output is shown in Figure 7. The calibration curve developed for the perox-ide/catalase system is linear from O.OO M to 1.OM (Figure 8). The error bars shown in the calibration curve were calculated by multiplying the standard deviation by the 95 /. confidence limit for a set of data with four degrees of freedom. The correlation coefficient of the line is... 

Claeys-Thoreau (1982) and DeBenzo et al. (1990) diluted blood samples at a ratio of 1 10 with a matrix modifier (0.2% Triton X-100, a wetting agent) for direct determinations of CDB. DeBenzo et al. also demonstrated that aqueous standards of cadmium, instead of spiked, whole-blood samples, could be used to establish calibration curves if standards and samples are treated with additional small volumes of matrix modifiers (i.e., 1% HNO3, 0.2% ammonium hydrogenphosphate and 1 mg/ml magnesium salts). 

Absolute values for the ti iplet quantum yield were obtained by extrapolating the slope of the saturation curves to zero excitation intensity and converting the measured laser intensity to the number of incident photons per cm using free chlorophyll a in Triton X-100 at 77K as a calibration standard. For the calculation the following values were assumed triplet quantum yield d>chi = 0.6 and echi = 100 000 M cm" The number of triplets per pigment were approximated by the ratio of the integrals of both the AA (at time zero) and A spectra from 648 to 690 nm for free chlorophyll and from 655 to 695 nm for the complexes. 

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