Touching a woman does not invalidate Wudhu' in any circumstances, according to the most authoritative opinion of the scholars. This is because it has been authentically reported from, the Prophet- sallallahu alaihi wasallam- that he use to kiss some of his wives, and then he would pray, without performing Wudhu'( Abu Dawud nos.178, 179 and At-Tirmithi no.86)
A woman should not shake hands with any man who is not a,Mahram ( Her Husband and any other man that she cannot marry such as a brother, uncle etc.) for her, just as a man should not shake hands with a women for whom he is not a Mahram, based upon the saying of the Prophet-Sallallahu alaihi wasallam. Verily I do not shake hands with a women ( An-Nasa'I no. 4186 and Al-Muwattta no.2) and what has been authentically reported from A'ishah may Allah be pleased with her, that the Prophet -Sallallahu alaihi wasallam- used to accept the pledges of allegiance from women in words only; she said : And no women ever touched his hand( Al Bukhari nos.2713,4891,5288,7214 and Muslim no. 1866.
And Allah, the Most High says: Indeed in the Messenger of Allah ( Muhammed) you have a good example to follow ( Al- Ahzab 33:21)
Also, Women shaking shaking hands with men and men shaking with women whom they are not closely Mahram for is a cause of Fitna for all. And Islamic law which is perfect, prevents all things which lead to that which Allah has forbidden.
From the above, it is clear that the Ajnabiyyah women is one whom it is not forbidden for him to marry due to kinship or another legal reason- this is Ajnabiyyah. As for the one whom he cannot marry due to ties in kinship, such as his mother, his sister, his aunt, or any other legal constraint, such as breastfeeding or relationship by marriage, she is not an Ajnabiyyah. And with Allah is success.